What’s New from OB Images
August 31, 2017
Early Diagnosis of Bladder Exstrophy: Quantitative Assessment of a Low-Inserted Umbilical Cord. J Ultrasound Med. 2017 Sep:1801-1805. Fishel-Bartal M, Perlman S, Messing B, Bardin R, Kivilevitch Z, Achiron R, Gilboa Y.
The diagnosis of bladder exstrophy, a rare congenital anomaly, is difficult. These authors describe a technique to assess for this condition at less than 18 weeks’ gestation. If the urinary bladder was not visualized, the authors measured the length between the umbilical cord insertion and the genital tubercle. The measurement was taken in the midsagittal plane, similar to a nuchal translucency assessment and the fetus was kept in a neutral position. Using this technique, all 6 cases of bladder exstrophy were diagnosed. The criteria for diagnosis is the umbilical cord insertion to the genital tubercle length of below the fifth percentile for gestational age. A normative chart for these measurements is provided in the published report.
August 14, 2017
Increased nuchal translucency thickness and risk of neurodevelopmental disorders. Ultrasound Obstet Gynecol. 2017 May;49(5):592-598. Hellmuth SG, Pedersen LH, Miltoft CB, Petersen OB,Kjaergaard S, Ekelund C, Tabor A
This study looked at the relationship between fetal nuchal translucency (NT) thickness and neurodevelopmental disorders in children with normal chromosomal number. The data included 222,505 children who had undergone routine first-trimester screening during fetal life. Children were divided according to prenatal NT and were followed-up to a mean age of 4.4 years. Follow-up information was obtained relative to intellectual disability, autism spectrum disorders (ASD), cerebral palsy, epilepsy and febrile seizures. In summary, there was no increased risk of neurodevelopmental disorders among those with a first-trimester NT 95(th)-99(th) percentile. Among children with a prenatal NT of > 99(th) percentile, the absolute risk of intellectual disability and ASD was reassuringly low (< 1%).
July 19, 2017
Preterm delivery after fetoscopic laser surgery for twin-twin transfusion syndrome: etiology and risk factors. Ultrasound Obstet Gynecol. 2017 May;49(5):612-616 Malshe A, Snowise S, Mann LK, Boring N, Johnson A, Bebbington MW, Moise KJ Jr, Papanna R
This study sought to address the factors related to preterm delivery after fetoscopic laser surgery (FLS) for twin-twin-transfusion syndrome (TTTS). The results are from a single center reviewing 203 patients with TTTS who underwent FLS. The mean gestational age at FLS was 20.6 ±2.4 weeks with delivery occurring at 30.9 ± 4.7 weeks. Preterm premature rupture of membranes (PROM) occurred in 39% of cases with spontaneous preterm delivery in 48%. Risk factors for spontaneous preterm delivery were iatrogenic preterm PROM, preoperative cervical length, and number of anastomoses.
July 10, 2017
Early prediction of twin-to-twin transfusion syndrome: systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2017 May;49(5):573-582.Stagnati, Zanardini, Fichera A, Pagani, Quintero RA, Bellocco, Prefumo F
This study undertook an evaluation of the performance of certain first and second trimester markers to predict twin-to-twin transfusion syndrome (TTTS) in monochorionic twin gestations. Ultrasound parameters, measured before 16 weeks, were reviewed in 1991 such pregnancies. The following ultrasound parameters demonstrated an increased risk for the development of TTTS in monochorionic pregnancies: NT discrepancy, NT > 95th percentile, CRL (crown rump length) discrepancy >10%, abnormal ductus venosus flow on first trimester ultrasound.
June 17, 2017
The Role of Early Gestation Ultrasound in the Assessment of Fetal Anatomy in Maternal Obesity.
J Ultrasound Med. 2017 Jun;36(6):1161-1168. doi: 10.7863/ultra.16.06083. Epub
2017 Apr 18.
Romary L, Sinkovskaya E, Ali S, Cunningham TD, Marwitz S, Heeze A, Herlands L, Porche L, Philips J, Abuhamad A.
A 2012 consensus suggested that ultrasound examinations in obese patients should be performed at 20 to 22 weeks and, when anatomy is incomplete, a follow up scan should be performed in 2 to 4 weeks. The question posed by this study was: Could imaging performed earlier in the pregnancy improve visualization of fetal structures? In obese patients with a BMI of >30, with a singleton gestation, and no karyotype abnormality, an ultrasound performed at (13 + 0 to 15 + 6 weeks) and was compared with the traditional second-trimester ultrasound. This obese group was compared to women with a singleton gestation, no karyotype abnormality, age > than 18 years, and at < 16 weeks’ gestation, and with a BMI of less than 30. Both groups underwent a transvaginal and/or transabdominal sonogram for fetal anatomic survey at 13 + 0 to 15 + 6 weeks’ gestation (US1). Those in the study also underwent a transabdominal sonogram at 18 to 24 weeks (US2). A repeat transabdominal sonogram (2-US2) was performed 2 to 4 weeks later if US1 failed to detail anatomy.
In summary, the authors found that the highest benefit for the addition of an early ultrasound was for women with Class III obesity (BMI > 40 kg/m(2).
June 5, 2017
New links to Zika virus information.
The following are public links from the New England Journal of Medicine on the Zika virus:
Testing Zika Virus Vaccines: May 11, 2017 | S.J. Thomas . Two studies of messenger RNA Zika virus vaccines show that they protect against infection in animal models.
In summary, this discussion is about 2 potential Zika virus vaccines which have been tested in animals. While research and development to date has been impressive, it is not clear whether the Zika virus acts like a flavivirus or dengue virus. If it acts like a flavivirus, chances for successful vaccine development may be greater. The goal is to protect women from the Zika virus through active immunization. However, at this time active research continues towards developing an effective vaccine.
Cutaneous Eruption in a U.S. Woman with Locally Acquired Zika Virus Infection. N Engl J Med 2017; 376:400-401January 26, 2017DOI: 10.1056/NEJMc1610614
In summary, this is a case report of acquired Zika virus in a pregnant woman who had not traveled outside of the United States. Positive findings at 23 weeks gestation were: erythematous follicular macules and papules on the trunk and arms, scattered tender pink papules on the palms, and a few petechial lesions on the hard palate. Histology of the skin lesion showed: a mild perivascular lymphocytic infiltration in the upper dermis, admixed with some neutrophils. ZIKV RNA was detected in both urine and serum specimens, using a reverse-transcriptase polymerase chain reaction (RT-PCR). Occurring in Florida, this is the first non–travel-associated case of ZIKV infection in the United States
May 4, 2017
Utility of ultrasound examination at 10-14 weeks prior to cell-free DNA screening for fetal aneuploidy. KL Vora, S Robinson, EE Hardisty, and DM Stami1
In this study, 1806 women with advanced maternal age (AMA) underwent a 10-14 week ultrasound study and aneuploidy screening, 68.5% of whom selected cell free DNA screening. Among these women, 16.1% had an ultrasound finding such as anomaly, incorrect dating, multiple gestation and non-viable pregnancy which may have altered recommendations as to the screening or testing decisions. The authors recommend a 10 to 14 week ultrasound study prior to cell free DNA testing in AMA women.1
May 5, 2017
Ultrasound Obstet Gynecol. 2017 Apr;49(4):493-499. doi: 10.1002/uog.17211. Diagnostic accuracy of individual antenatal tools for prediction of small-for-gestational age at birth.Poljak B, Agarwal U, Jackson R, Alfirevic Z, Sharp A.2
A number of fetal and newborn growth charts for estimated fetal weight (EFW) were compared to assess the accuracy of these charts at <10th percentile to predict small-for-gestational age (SGA) at birth. The various ultrasound charts assessed were among those pregnancies excluded on the basis of abnormal Doppler. The authors cite wide variation in the accuracy to predict the SGA fetus and to predict adverse perinatal outcome. All of the present EFW charts have low rates of detection for SGA. The authors suggest using a combination of fetal biometry and EFW with placental biomarkers to detect SGA and adverse perinatal outcome.2
March 7, 2017
Valent AM, Newman T, Kritzer S, Magner K, Warshak CR. Accuracy of Sonographically Estimated Fetal Weight Near Delivery in Pregnancies ComplicatedWith Diabetes Mellitus. J Ultrasound Med. 2017 Mar;36(3):593-599. doi: 10.7863/ultra.15.12021.3
The study’s purpose was to evaluate the accuracy of ultrasound estimated fetal weight (FW) within 2 weeks of delivery and the signed percent error (the mean ± standard deviation) between patients with and without Diabetes. The study population was composed of 6843 births. The authors found no significant difference between the two groups for the accuracy of estimated FW near delivery or of signed percent error. Sonography had a high specificity (the extent to which estimated FW really represents birth weights of greater than 4000 grams).3
Above, Module 1. Title: Fetal Echocardiography: Introduction to Situs and Critical Views. 1.0 Credit AMA PRA Category 1 CreditTM; $19 (You may access this course at any time until January, 26 2019.)
Above, Module 2. Title: Fetal Echocardiography: Normal Cardiac Views. 1.5 Credit AMA PRA Category 1 CreditTM; $19 (You may access this course at any time until January, 26 2019.)
Above, Module 3. Title: Fetal Echocardiography: Abnormal Fetal Heart Diagnosis (Pathways and algorithms). 3.0 Credit AMA PRA Category 1 CreditTM; $49 (You may access this course at any time until January,26 2019.)
Above, Title: Prenatal Diagnosis: Congenital Diaphragmatic Hernia. 2.0 Credit AMA PRA Category 1 CreditTM; $19 (You may access this course at any time until January, 26 2019.)
For all 3 Fetal Echocardiography Courses, 20% discount: $49
If you are interested in any of the CME courses, please click this link and register:
February 5, 2017
Welcome to Obimages.net’s new theme and features. The navigation is rapid, intuitive and responsive to phone, ipad, and PC to facilitate point of care ob ultrasound information, images, and videos, and now there is a feature to share your interesting cases. The CMEs: AMA PRA Category 1 CreditTM internet-based video courses are offered for physicians and sonographers (accepted by ARDMS).
Longitudinal Assessment of Examiner Experience and the Accuracy of Sonographic
Fetal Weight Estimation at Term.
Faschingbauer F, Heimrich J, Raabe E, Kehl S, Schneider M, Schmid
M, Beckmann MW, Hepp T, Lübke A, Mayr A, Schild RL.4
This study seeks to assess the influence of the ultrasound scanner’s experience on the accuracy of ultrasound estimation of weight and to analyze the scanner’s individual learning curves.
This was a multicenter study in which 4613 ultrasound weight estimations were performed
by 18 examiners at the beginning of their ultrasound training. Variables to determine
ultrasound errors were applied, and the examiner’s experience was evaluated including the number of examinations. In addition, the individual learning curves of the examiners was determined.
After adjustments, there was a significant influence related to the number of examinations on the accuracy of sonographic weight estimation (P < .001). A typical learning curve with
improving accuracy was found at approximately 200 examinations. The diagnostic performance started to deteriorate again between 200 and 300 examinations. The authors stress the importance of continuous quality control for ultrasound weight estimation.
Cervical cerclage for preterm birth prevention in twin gestation with short cervix: a retrospective cohort study.
Houlihan C, Poon LC, Ciarlo M, Kim E, Guzman ER, Nicolaides KH.5
The purpose of the study was to determine whether the application of cervical cerclage reduces the rate of premature birth in dichorionic diamniotic (DCDA) twins who have a short cervix detected by ultrasound. In 40 consecutive DCDA twin gestations, cervical cerclage was performed for an ultrasound derived cervical length of 1-24 mm at 16-24 weeks’ gestation. There were
40 control patients who did not undergo cerclage and who were matched for gestational age and cervical length with the cerclage group. In the cases with cerclage application compared with controls, spontaneous delivery < 32 weeks was significantly less frequent (20.0% vs 50.0%; relative
risk, 0.40 (95% CI, 0.20-0.80)). Women who underwent cerclage were less likely to spontaneously deliver at < 32 weeks. In summary, in DCDA twin gestation with a short cervix, treatment with cervicacerclage may reduce the rate of early preterm birth. The authors suggest the need for further
adequate randomized controlled trials on cerclage in twin gestations with a short cervix.
Prediction of stillbirth from biochemical and biophysical markers at 11-13 weeks.
Mastrodima S, Akolekar R, Yerlikaya , Tzelepis T, Nicolaides KH.6
Prediction of stillbirth at 11 to 13 weeks was based upon a model which combined maternal characteristics and maternal medical history with first trimester biochemical and biophysical markers.
The study’s objectives were to evaluate how the screening by this model was predictive for all stillbirths and those due to impaired placentation and to unexplained causes.
In this study 76 897 singleton pregnancies were screened. Among these, there were 268 (0.35%) antepartum stillbirths. Among the stillbirths, 59% were due to impaired placentation and 41% were due to other or unexplained causes. Multivariable logistic regression analysis considered the following factors: maternal factor-derived a-priori risk, fetal nuchal translucency thickness, ductus venosus pulsatility index for veins (DV-PIV), uterine artery pulsatility index (UtA-PI) and maternal serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein-A (PAPP-A).
A model combining these variables predicted 40% of all stillbirths and 55% of those due to impaired placentation, with a false-positive rate of 10%. The authors stress that prevention of stillbirths remains to be determined.
Neonatal Outcomes in Fetuses With a Persistent Intrahepatic Right Umbilical Vein.
Canavan TP, Hill LM7
Persistent right umbilical vein may be associated with abnormal findings in the fetus or may be a normal finding. In this study, 313 fetuses were noted on the 17 to 24 week ultrasound to have a persistent right umbilical vein identified, which was defined as a left curving umbilical vein passing to the right of a medially displaced gall bladder. An adverse event was defined as aneuploidy, fetal demise or neonatal death. A normal neonatal outcome was reported in 69.3% (217 patients). Adverse outcomes included 5 fetuses with aneuploidy, and 24 fetuses with major anomalies. There were 2 neonatal deaths and 1 fetal demise. In the presence of a persistent intrahepatic right umbilical vein, the authors stress the importance of a complete anatomic and cardiac evaluation with further appropriate referral as needed.
September 24, 2016 “Newsletter 3 on Preterm labor prediction and normal 3 vessel trachea view” is available in the “Archived Newsletter” section.
August 10, 2016 Diagnosis of Tetralogy of Fallot (TOF)
July 16, 2016
Archived newsletters will be published on a periodic basis: topics include Zika virus, and Ebstein anomaly, and aneuploidy screening and D-transposition of the great arteries.
June 24, 2016
We are celebrating the two year anniversary of the launch of obimages.net, dedicated to those providing obstetrical ultrasound care. We are proud of the world-wide response to this effort and are committed to continually updating information and images. We are grateful to our sponsors: GE Healthcare, Philips Ultrasound, and Samsung 5-D ultrasound for their support, which allows the site to remain free and easily accessible.
March 2, 2016, Pregnancy attempt after an early pregnancy loss
February 8, 2016, Solomon Technique versus Selective Laser Ablation for TTTS
January 29, 2016, Zika Virus Infection In Pregnancy
January 27, 2016, Rate of incomplete scans, second trimester
January 9, 2016, All new video section
January 1, 2016, Sonographic Detection of Growth Restriction in Gastroschisis
December 22, 2015, Cervical length and C-section in Twins
December 11, 2015, Examples of the most viewed videos on obimages.net
November 28, 2015, Trial of Progesterone in Women with Recurrent Miscarriages
November 25, 2015, Analysis of cell-free DNA in maternal blood
November 17, 2015, New Chapter: Fetal Interventions (Invasive Fetal Procedures)
October 30, 2015, Twin anemia-polycythemia sequence (TAPS)
October 16, 2015, Fetal Heart (11-13 week scan),
October 16, 2015, Placenta Accreta (Triple P Procedure)
September 29, 2015, Chapter Updates: Vasa previa
September 29, 2015, Chapter Updates: Fetal Doppler
September 29, 2015, Chapter Updates: Congenital diaphragmatic hernia
August 21, 2015, New Chapter Posted: Transvaginal ultrasound of the cervix
Page Links to Other What’s New?
June 24, 2015: A Preterm labor delivery (PTD) calculator link has been added to Calculators. Data for the calculator is based upon fetal fibronectin, transvaginal cervical length in mm, and C-reactive protein.
Imaging Characteristics for 13 Congenital Heart Defects
The following E-poster won Second Place in Obstetric Ultrasound: Fetal Anomalies category at the 2015 Annual American Institute for Ultrasound in Medicine (AIUM) meeting, March 2015:
Practice Bulletin on Early Pregnancy Loss
A new practice bulletin on “Early Pregnancy Loss” has been published by The American College of Obstetricians and Gynecologists. If medical management is indicated, 800 micrograms of vaginal misoprostol is recommended with a repeat dose, if needed. Expectant management or surgical evacuation are also acceptable treatment options. If the patient is Rh(D) negative and not sensitized, she should receive 50 micrograms of Rh(D) immune globulin immediately after surgical management or within 72 hours of a diagnosis of early pregnancy loss when expectant or medical management is planned.
Early pregnancy loss diagnostic criteria are provided by transvaginal ultrasound during the first trimester.
Errors exist during the early first trimester in correctly assigning whether the pregnancy is viable, nonviable, or in an ectopic location. The false positive rate (incorrect diagnosis of a not viable pregnancy when the pregnancy is normal) is as high as 4.4%.
In a recent review, transvaginal ultrasound diagnosis of pregnancy failure in a pregnancy with uncertain viability is as follows:
CRL (crown rump length) of ≥ 7mm and no evidence of heartbeat,
MSD (mean sac diameter) of ≥ 25 mm and no embryo visualized,
Initial scan shows a gestational sac without a yolk sac followed by a scan ≥ 2 weeks later demonstrating the absence of embryo with heartbeat,
Initial scan shows a gestational sac with a yolk sac followed by a scan ≥ 11 days later showing the absence of embryo with heartbeat,
If viability remains unclear, repeat the TVS in 11 to 14 days.
Table Summaries for 11 Congenital Heart Defects
Tabular summaries are presented at the beginning of the sections for 11 congenital heart defects (CHDs), which tabulate either images or descriptions of these CHDs according to the major cardiac views: 4 chamber view, LVOT (left ventricular outflow tract), RVOT (right ventricular outflow tract), and 3-VV or 3-VT (3 vessel tracheal view). These fetal heart sections, in addition to other CHD topics, contain detailed information, imaging considerations, images and videos. The 11 CHDs with summaries include: Hypoplastic Left Heart, Ebstein Anomaly, Tetralogy of Fallot, Isolated VSD, Atrioventricular Septal Defect, Coarctation of the Aorta, Valvular Aortic Stenosis, Double Outlet Right Ventricle, Dextro-Transposition of the Great Arteries, Congenitally Corrected Transposition of the Great Arteries, and Truncus Arteriosus (Common Arterial Trunk).
Tricuspid Valve Dysplasia
Tricuspid valve dysplasia (TVD), a new topic, has been added to the cardiac section with Ebstein anomaly. For details see the chapter. Tricuspid Valve Dysplasia (TVD) is part of a spectrum of congenital heart abnormalities which includes Ebstein Anomaly (EA). In 1991, Sharland and colleagues helped define these relationships. 
Above: Ebstein anomaly with displacement of the tricuspid valve, atrialized right ventricle (ARV) and functional right ventricle (FRV); RA= large right atrium, LV=left ventricle, RV=right ventricle.
Above: Tricuspid valve dysplasia. No displacement of the TV (tricuspid valve); RA= large right atrium, LV=left ventricle, RV=right ventricle.
In another study of 27 fetuses with EA and TVD, associated cardiac lesions included pulmonary stenosis and pulmonary atresia.  In addition, sequential changes in some fetuses demonstrate retrograde flow in the pulmonary artery and ductus arteriosus. Antenatal and neonatal mortality was high with over 50% of autopsy findings suggesting lung hypoplasia.
Methods for Recommending Due Date
Posted February 16, 2015
Recommendations for estimating gestational age and due date are presented by The American College of Obstetricians and Gynecologists (ACOG) (Committee Opinion 611 in October 2014): These recommendations were formulated by the ACOG, the American Institute of Ultrasound in Medicine, and the Society for Maternal-Fetal Medicine.
1. The most accurate method to establish or confirm gestational age is a CRL taken up to 13 6/7 weeks.
2. In the case of assisted reproduction, the age of the embryo and the date of transfer should be used.
3. The last menstrual period (LMP), and the first accurate ultrasound examination should be the basis for the expected due date (EDD), discussed with the patient and recorded in the medical record.
4. Using criteria in the document the best obstetric estimate is recommended for the purposes of clinical care while the criteria for research and surveillance are presented.
The following chart summarizes the guidelines for re-dating the pregnancy on the basis of the ultrasound findings when there is a difference between the ultrasound dates and the LMP (last menstrual period).
Fetal Heart Chapter: Fetal situs
Posted January 31, 2015. See: Situs or sidedness: The first step in assessing the fetal heart.
Fetal Heart Graphics
Posted January 6, 2015
The Fetal Heart section on obimages.net has expanded information and graphics. For each major fetal heart topic, there is now a section with post-delivery (neonatal) graphic anatomy of the congenital heart defect. For example, these graphics under “Post-delivery graphic anatomy” start with the chapter “Hypoplastic Left Heart Syndrome” and continue with the other major cardiac chapters. These graphics define and illustrate many of the features seen on the fetal scan.
December 16, 2014
Recent papers have reviewed and clarified diagnostic and sonographic features of placenta accreta. Please see Summary Placenta Accreta chapter for details.
International standards: fetal size and pregnancy dating by crown-rump length (CRL) during the first trimester of pregnancy
December 5, 2014
International standards are published for fetal size and pregnancy dating by crown-rump length (CRL) during the first trimester of pregnancy. The study included 4321 women with live singleton births from uncomplicated pregnancies. Eligibility criteria was from eight diverse countries with pregnancies recruited between 9 + 0 and 13 + 6 weeks. The study was designed to reduce methodical errors and to serve as an international standard for relating CRL to gestational age (GA). The entire article is open access for viewing and may be downloaded to obtain charts and tables related to CRL and GA.These charts are reproduced in the first trimester normal chapter under “International standards for CRL and GA.”
October 21, 2014
A review by Wenstrom and Carr updates the present status of fetal surgery. An historical perspective is given and closed and open surgical therapies are discussed. For details, please see their original article. . The following is a summary of significant findings.
Intrauterine fetal transfusion
Intravascular fetal transfusion through the umbilical vein is presently the standard of care for fetal anemia and following Mari’s  work suggesting that the peak systolic velocity of the middle cerebral is highly sensitive in determining fetal hemoglobin levels, amniocentesis is not employed to detect fetal anemia.
Lower urinary tract obstruction
Prognosis is difficult to define among fetuses with lower urinary tract obstruction but the best predictors of poor outcome are oligohydramnios and the presence of renal cortical cysts.  Fetal urinary analytes are not predictors of poor outcome with the exception of elevated urinary calcium and elevated sodium.  While many issues require clarification, the efficacy for intervention in lower urinary tract obstruction is not clearly established.
Placental laser photocoagulation for twin-twin transfusion syndrome (TTTS)
Survival rates are greater with laser coagulation of connecting vessels in TTTS (55% to 69% with neurologic abnormalities in 5% to 11% of survivors) compared with other treatment options such as septostomy and amnioreduction. Coagulation of the entire vascular equator may confer certain benefits compared to standard laser therapy. 
Pleural effusions are a complex group of abnormalities which may be isolated or primary (no association with other fetal conditions) or secondary (associated with fetal anomalies or conditions). In addition effusions can be due to lymph fluid or fetal hydrops. Outcomes are unpredictable and some effusions undergo spontaneous regression. While there is no strong consensus for intervention, the following has been proposed : Interventions may be warranted in the presence of fetal hydrops with pleural effusion as the etiology, isolated pleural effusion occupying over 50% of the thoracic cavity with mediastinal shift, rapid increase in pleural effusion associated with polyhydramnios, and isolated pleural effusion without anomaly.
Open Surgical Therapies
The Management of Myelomenigocele trial compared fetuses undergoing prenatal surgery to a group undergoing postnatal repair. The study results are numerous. Please see the original report for details.  In summary, those undergoing prenatal surgery were less likely to experience fetal or neonatal death, less likely to meet criteria to have a shunt placed or to have hindbrain herniation, more likely to have motor function, to walk, and to have better neonatal psychomotor scores. Tests of functional independence and cognitive scores were similar, while pregnancy complications were greater in the prenatal surgical group and more children in the prenatal group required surgery for tethered cord (8% versus 1%).
Congenital diaphragmatic hernia (CDH)
Prenatal surgical intervention in CDH is typically offered to the most severe cases with the worst prognosis or life expectancy. The results for prenatal tracheal occlusion (intended to accelerate fetal lung growth) are mixed and proof of efficacy is difficult to determine. Poor prognostic fetuses (lung-to-head ratio of <25% for left CDH and <45% for right CDH) could potentially benefit from fetoscopic endotracheal occlusion. 
Fetal tumors are rare but the tumors most likely to require consideration for antenatal surgery are sacrococcygeal teratomas (SCT) and thoracic masses such as cystic adenomatoid malformation and pulmonary sequestration. In each, the presence of fetal hydrops is a prime determinant of outcome. SCT can be associated with arterial-venous malformations leading to cardiomegaly and high output failure, and a variety of other associated malformations. Numerous therapies have been reported for SCT (open fetal surgery, radiofrequency ablation, laser vessel ablation, alcohol sclerosis, and cyst drainage). Since prognosis is poor in the presence of fetal hydrops, delivery is a viable treatment option.
Non-Invasive Prenatal Testing (NIPT) and Prenatal Ultrasound Practice
September 27, 2014
The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) recently published (June 3, 2014) a consensus statement on the topic of non-invasive prenatal testing (NIPT) as this new testing method relates to prenatal ultrasound practice. For details of this statement, please refer to the original document.
In summary, women should be offered a 1st trimester ultrasound (US) (11 to 13 6/7 weeks) according to ISUOG recommendations  preceded by pre-test counseling.
The following is an algorithm summarizing a part of the ISUOG consensus statement.
First Trimester Diagnostic Criteria for Nonviable Pregnancy
September 14, 2014
In order to avoid interruption of a normal pregnancy, criteria for a nonviable pregnancy includes the following in the presence of an empty sac: a mean sac diameter of 25 mm or greater and a crown rump length of 7 mm or greater. In a retrospective review Hu, Poder, and Filly determined that only 12% of 1013 threatened abortions met these present conservative guidelines for non-viability as recommended by the Society of Radiologist. Clearly, there is much room for improvement. Also see below: Pregnancy viability. This topic is further summarized at the end of “The first trimester: normal exam” chapter.
Placental Mesenchymal Dysplasia (PMD)
August 30, 2014
Images courtesy of Krishnan Raghavan, MD, Scrinivas Ultrasound Scan Centre, Cuddalore, India
Above. Left. 20 5/7 weeks. Note enlarged placenta with multiple hypoechoic, cystic-like spaces. Right. 20 5/7 weeks. A portion of the placenta is unaffected and the umbilical artery Doppler resistance is normal, while the fetus appears structurally normal.
Above. Left. Same patient as above. 37 4/7 weeks. Note enlarged placenta with multicystic spaces. Color Doppler does not suggest increased blood flow. Right. Same patient. 37 4/7 weeks. The cystic areas represent large hydropic stem villi. A viable infant was delivered at term and histopathology confirmed the diagnosis of PMD.
Placental mesenchymal dysplasia (PMD) is a disorder in which a large multicystic placenta is most often associated with a normal fetus. The condition was described in 1991, occurs in approximately .02% of pregnancies, while about 100 cases have been reported to date.  About 89% of the cases are associated with a normal karyotype and 23% are associated with Beckwith-Wiedemann syndrome, while other complications include fetal growth restriction and intrauterine fetal death.  Differential diagnosis includes gestational trophoblastic disease, the histology of which demonstrates trophoblast proliferation, while PMD demonstrates large hydropic stem villi. Suspect PMD when there is a multicystic placenta in the presence of a normal fetus. Close fetal surveillance is warranted.
Normal CNS Video
August 21, 2014
Above: Video, normal fetal CNS at 22 2/7ths weeks. Courtesy of Dr. Mayank Chowdhury; Pallav Imaging Institute, Mayflower Women’s Hospital, Ahmedabad, India.
Key fetal anatomy includes the choroid plexus, the septum cavum pellucidi (SCP), lateral ventricles, and the corpus callosum.
The pericallosal artery is a continuation of the anterior cerebral artery and it continues superiorly and posteriorly supplying the corpus callosum and the medial aspect of the cerebral hemisphere.
Umbilical Cord Cyst
August 18, 2014
Mid-trimester scan. Courtesy: Firoz Bhuvar, MD (World Ultrasound, color Doppler and Echo Society)
August 10, 2014
Commentary, Michelle Proctor, MD: “Umbilical cord cyst possibilities include pseudocyst or true cyst– allantoic or omphalomesenteric duct cyst.” The cyst wall is thickend and may have “epithelial cell lining plus the cyst is centrally located” and there is “widening of the umbilical arteries.” The cyst is near the fetal cord insertion site. Given these findings “allantoic cyst” most likely but final diagnosis awaits follow up and histology following birth. For more information on umbilical cord cysts, see umbilical cord cysts.
July 31, 2014
Two new topics have been added to “1st Trimester” category: “First Trimester Abnormalities”, and “First Trimester: Normal and Some Abnormal Images”.
July 22, 2014
Two new first trimester topics have been added to the “1st Trimester” category: “Bleeding/miscarriage/molar changes”, and “Ectopic pregnancy”.
A new topic has been posted under “1st Trimester” (The first trimester: normal exam). This will be followed by other topics outlining abnormalities during the first trimester.
July 22, 2014
An important task is to define normality in the first trimester by correctly assigning whether a pregnancy is viable, nonviable, or in an ectopic location. The false positive rate (incorrect diagnosis of a not viable pregnancy when the pregnancy is normal) can be as high as 4.4%.  A recent review  defines pregnancy failure and specifies cutoff values for this purpose. These values are summarized at the end of “The first trimester: normal exam” topic.
From time to time, research or reviews which enhance current understanding of obstetrical ultrasound are shared with website visitors.
The diagnosis and management of fetal cardiovascular disease is presented as a scientific statement from the American Heart Association and covers diagnosis of congenital heart disease, arrhythmias, and available treatment options. Cardiac anatomy, function, and rhythm are reviewed as well as the essentials of the fetal echocardiogram. The full text link is available as a download. 
A current commentary and executive summary on fetal imaging is presented as a result of a workshop hosted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The workshop, representative of multiple organizations concerned with maternal and fetal health, reviews frequency and performance of MRI and ultrasound. Issues related to optimization of yield, costs and research are reviewed. Useful recommendations are provided regarding soft markers observed during second trimester ultrasounds, and are summarized at the end of the Genetic Marker topic Imaging Considerations. 
Other Updates and Links
’’Trial of Progesterone in Women with Recurrent Miscarriages’,
’Analysis of cell-free DNA in maternal blood’,
’Balloon Catheters for Placenta Accreta’,
’Predicting anemia in TAPS’,
’Detection of fetal Cardiac Defects (11 to 13 Weeks)’,
’Placenta Accreta and Triple P Procedure’,
’Ultrasound Accuracy and Vasa Previa’,
’Fetal Doppler and Late Onset PIH’,
’Small for SGA Prediction’,
’Congenital Diaphragmatic Hernia’
Role of 3-Vessel Trachea View in the Diagnosis of Tetralogy of Fallot
Role of 3-Vessel Trachea View in the Diagnosis of Tetralogy of Fallot.
The role of the 3 vessel and trachea view in the prenatal diagnosis of Tetralogy of Fallot (TOF) is addressed in a recent article.  The diagnostic frequency of TOF is low (32% to 47%) and methods to improve accuracy are pursued. Despite the classic anatomic defects of override of the aortic root over a ventricular septal defect (VSD) and infundibular pulmonary stenosis, the diagnosis is often missed. In this study, the 3 vessel and trachea view was abnormal in TOF and on that view, the single most important marker is an enlarged aortic arch isthmus compared to the pulmonary artery. Normally the pulmonary artery is larger than the aorta and the pulmonary valve is larger than the aortic valve but in TOF the aortic valve is larger than the pulmonary valve. These findings were present in all fetuses with TOF on the 3-vessel trachea view.
Prediction of spontaneous preterm birth among nulliparous women with a short cervix.
Prediction of spontaneous preterm birth among nulliparous women with a short cervix
The object of the study was to determine whether women with a short cervix (cervical length of <30 mm.) could be included in an accurate prediction model for preterm birth if additional demographic and sonographic factors were included in the model. A secondary analysis was performed of trials among women with a cervical length of <30 mm. obtained at 16 to 22 weeks who did not have other risk factors for spontaneous or medically indicated preterm birth. Risk factors known to be associated with spontaneous preterm birth were included in a regression analysis to determine if these factors could improve prediction in women with a cervical length of <30 mm. Despite inclusion of these risk factors in those women with a short cervix, an accurate prediction model could not be developed.
Note: according to the authors, at 16 to 22 weeks gestation, the 10th percentile for cervical length is 30 mm. Among women in the United States, the risk for preterm birth in this group is 25%.
Accuracy of ultrasound in the antenatal detection of placental disorders
Accuracy of ultrasound in the antenatal detection of placental disorders.
The purpose of the study was to determine the accuracy of ultrasound in the detection of placenta accreta and the effect on outcome as it relates to prenatal diagnosis.  Among 314 patients prospectively studied with suspected placenta previa, 37 met ultrasound criteria for placenta accreta. Detection rates for placenta accreta were better in the presence of an anterior placenta (89.7%) compared to women with a posterior placenta (50%). Women who had a placental attachment disorder diagnosed prenatally had less blood loss and shorter hospitalization. Gray scale and color had good overall performance for the diagnosis of placenta accreta.
Correlation between cervical lengths measured by transabdominal ultrasound and transvaginal ultrasound for the prediction of preterm birth.
Correlation between cervical lengths measured by transabdominal ultrasound and transvaginal ultrasound for the prediction of preterm birth
Due to the potential discomfort of transvaginal ultrasound, this study sought to determine whether the result of a transabdominal ultrasound measurement of cervical length could determine which women should undergo transvaginal ultrasound in order to predict preterm birth.  In this prospective study, measurements of cervical length were taken between 20 and 29 weeks gestation. Transabdominal ultrasound cervical lengths which are not measureable or <2.0 or <2.5 cm. indicate the need for transvaginal ultrasound for the prediction of premature birth, while women whose cervix is measurable and long on transabdominal ultrasound may not require transvaginal ultrasound for prediction purposes.
ISUOG Interim guidance on ultrasound for Zika virus during pregnancy
ISUOG Interim guidance on ultrasound for Zika virus during pregnancy.
The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) has published: “Interim Guidance on ultrasound for Zika virus infection in pregnancy: information for healthcare professionals”. This guidance report acknowledges the potentially valuable information which may be obtained by ultrasound practitioners. The direct link to the report is: ISUOG Link.
Pregnancy attempt after an early pregnancy loss
Among couples trying to conceive after different intervals of pregnancy loss, the study assessed the time to pregnancy and live birth. The population consisted of 1083 women, aged 18 to 40 years with one or two early pregnancy losses. Couples with a 0 to 3 month interval (76.7%) compared to a greater than 3 month interval (23.4%) were more likely to achieve live birth with a significantly shorter time to pregnancy. The authors conclude “there is no physiologic evidence for delaying pregnancy attempt after an early loss”.
Cervical length and quantitative fetal fibronectin to predict spontaneous preterm labor (sPTL) in asymptomatic high-risk women
Cervical length and quantitative fetal fibronectin to predict spontaneous preterm labor (sPTL) in asymptomatic high-risk women.
Quantification of fetal fibronectin, cervical length measurements, and one or more high-risk clinical historical factors were used to construct a predictive tool for spontaneous preterm labor (sPTL) in high-risk women.  The final model was predictive of sPTL and the areas under the receiver-operating curves ranged from 0.77 to 0.99 suggesting accurate predictions across five delivery outcomes.
Solomon Technique versus Selective Laser Ablation for TTTS
Solomon Technique versus Selective Laser Ablation for TTTS.
This study is a systematic review of 2 cohort studies and 1 randomized controlled trial (RCT) comparing these two techniques for the treatment of twin-twin transfusion syndrome (TTTS) in diamniotic monochorionic twins.  The findings suggest that the Solomon technique is associated with a trend towards reduction in TAPS (Twin Anemia-Polycythemia Sequence) and recurrent TTTS, while survival is increased without adverse effects or events. The authors suggest the need for further RCTs with long term neurological follow up.
Zika Infection in Pregnant Women
Zika virus infection is transmitted by mosquitos and is generally mild and characterized by acute onset of fever, maculopapular rash, arthralgia, or nonpurulent conjunctivitis. Symptoms usually last from several days to 1 week. However, an outbreak in Brazil has resulted in maternal-fetal transmission and fetal findings of microcephaly or intracranial calcifications.
Pregnant women with a history of travel to an area with Zika virus transmission and who report two or more symptoms consistent with Zika virus disease (acute onset of fever, maculopapular rash, arthralgia, or conjunctivitis) during or within 2 weeks of travel, or who have ultrasound findings of fetal microcephaly or intracranial calcifications, should be tested for Zika virus infection in consultation with their state or local health department.
Maternal-fetal transmission of Zika virus has been documented throughout pregnancy. Zika virus RNA has been detected in the pathologic specimens of fetal losses. In the current outbreak in Brazil, a marked increase in the number of infants born with microcephaly has been reported. However, it is not known how many of the microcephaly cases are associated with Zika virus infection.
There is neither a vaccine nor prophylactic medications available to prevent Zika virus infection. The CDC recommends that all pregnant women consider postponing travel to areas where Zika virus transmission is ongoing. If a pregnant woman travels to an area with Zika virus transmission, she should be advised to strictly follow steps to avoid mosquito bites.
See complete CDC guidelines for pregnant women.
Rate of incomplete scans during second trimester
Rate of incomplete scans during second trimester.
Among 4000 women who underwent a second trimester scan a small percentage were incomplete due to unfavorable fetal position.  Among the study population, 4.2% returned for a follow up scan within 2 weeks. Only 1 view was need in a subsequent scan in 2.6%, while 1.6% required more than 1 view. The most difficult organs to visualize during the initial scan were: corpus callosum (1.8%), fetal face (1.7%), cerebellar vermis (1.1%) and fetal heart (1.0%).
A retrospective cohort study was performed, assessing 111 births with gastroschisis.  Growth restriction was diagnosed using Hadlock’s nomogram and was defined as an estimated fetal weight of less than the 10th percentile for gestational age. The sensitivity and negative predictive value for the sonographic prediction of the small for gestational age neonate was 90% by 32 weeks and approximately 95% after 32 weeks. A low birth weight percentile on the antenatal scan was not associated with an immediate increase in neonatal morbidity or mortality.
In this study 311 women with a twin gestation attempted vaginal delivery after 34 weeks. Second trimester cervical length was measured in these women to determine if there were an association with the risk of emergency Cesarean section. In nulliparous women, there was no relationship between second-trimester CL and Cesarean delivery. 
Three-dimensional (3-D) ultrasound compared with magnetic resonance imaging (MRI) in the diagnosis of Müllerian duct anomalies using is highly accurate.  After being suspected of a uterine anomaly on two-dimensional scanning, 60 women were evaluated with 3D ultrasound and with MRI. Compared with MRI, 3D ultrasound had a sensitivity of 83.3% for dysmorphic uteri. For hemiuteri, the sensitivity was 100%, and the kappa was 1.00. For septate uteri, the sensitivity was 100%, and the kappa was 0.918, and for bicorporeal uteri, the sensitivity was 83.3% and the kappa was 0.900. Therefore, 3DUS is highly accurate for diagnosing uterine malformations, and has a good level of agreement with MRI in the classification of different anomaly.
A Randomized Trial of Progesterone in Women with Recurrent Miscarriages 
A multicenter, double-blind, placebo-controlled, randomized trial was undertaken in 836 women. The aim was to determine whether supplementation with progesterone in the first trimester of pregnancy would increase the rate of live births among women with a history of unexplained recurrent miscarriages. Women were randomly assigned to receive either twice-daily vaginal suppositories containing either 400 mg of micronized progesterone or matched placebo. In women with a history of unexplained recurrent miscarriages, progesterone therapy did not result in higher rates of live births.
Analysis of cell-free DNA in maternal blood in screening for fetal aneuploidies: updated meta-analysis. 
A total of 37 studies were used for the meta-analysis. Trisomy 21 screening by cell-free DNA is superior to all methods of screening with a higher detection rate (DR) and a lower false positive rate (FPR), which leads to fewer unnecessary invasive procedures. The detection rate of screening by cell-free DNA for trisomies 18, 13 and sex chromosome aneuploidies is lower than that for Trisomy 21, and the authors do not suggest screening for fetal trisomies 18 and 13 independently from Trisomy 21 screening. While universal screening is associated with high costs, cell-free DNA testing contingent upon the results from first trimester ultrasound and biochemical testing is a strategy suggested by the authors.
Precesarean Prophylactic Balloon Catheters for Suspected Placenta Accreta. A Randomized Controlled Trial (Level of Evidence: 1) 
Twenty seven women were randomized to an intervention groups (13) who underwent prophylactic balloon catheter placement for suspected placenta accreta and 14 control patients who did not undergo placement. The outcome measure was the number of packed red blood cell units transfused, which did not differ between the two groups. Two of 13 women (15.4%) in the treatment group had reversible adverse effects. This is one of the few studies to address this issue and the authors acknowledge the small sample size and emphasize the difference between prophylaxis and treatment of postpartum hemorrhage by arterial embolization, which has been shown to be effective.
Middle cerebral artery (MCA) peak systolic velocity (PSV) predicts fetal hemoglobin levels in twin anemia-polycythemia sequence (TAPS) 
TAPS is a syndrome in monochorionic twin pregnancies resulting in the inter-twin transfusion of blood via small anastomosis. Occurring in approximately 13% of post laser treatment of twin to twin transfusion syndrome, TAPs results in significant hemoglobin differences between twins in the absence of evidence for oligohydramnios or polyhydramnios. A recent paper records 116 MCA-PSV measurements in 74 donors and 42 recipients with TAPS.
In fetuses with TAPS, MCA-PSV is diagnostic for predicting abnormal hemoglobin levels.
Fetal Heart (11-13 Week Scan) [See Screening Cardiac Exam)]
Prenatal detection of congenital heart defects at the 11-to-13 week scan using a simple protocol. 
In this prospective observational study performed at 11 to 13 weeks among 1084 patients, 35 cases were confirmed to have a congenital heart defect. The most effective approach was color mapping of the 4-chamber and 3-vessel and trachea views. The ideal insonation beam was 45 degrees with the fetal spine at 6 o’clock. The transducer assessed ventricular inflows in color at the level of the 4-chamber view, the 3-vessel view and finally demonstrating the V sign at the level of the 3-vessel trachea view. Using this approach a sensitivity of 88.5% and a specificity of 100% for the detection of CHD at 11 to 13 weeks. In addition, the vascular patterns for many of the defects are presented.
Placenta Accreta [See Maternal Outcomes]
Prevention of postpartum hemorrhage and hysterectomy in patients with morbidly adherent placenta (MAP) before and after the introduction of the Triple P procedure. 
The Triple-P procedure is a surgical method intended to reduce postpartum hemorrhage and hysterectomy in cases of placenta accreta, including placenta increta and percreta. Step 1 involves placental localization and delivery of the fetus via a transverse uterine incision above the upper margin of the placenta. Step 2 involves the inflation of pre-operatively placed occlusion balloons into both internal iliac arteries. In Step 3 the placenta is not separated and myometrial excision and reconstruction of the uterine wall is performed. If the bladder is invaded (percreta) the placenta is left in situ and hemorrhagic areas are treated with hemostatic powder. The Triple-P procedure resulted in reduced hysterectomy, post partum hemorrhage and hospital stay among a small cohort of patients. The authors acknowledge the need for further multicenter studies to confirm improved outcomes. Further, this procedure should be attempted only in centers with high levels of expertise among multiple disciplines. 
Accuracy of ultrasound in the diagnosis of vasa previa 
A recent systematic review of the accuracy of ultrasound in the diagnosis of vasa previa included 583 articles of which two were prospective and six were retrospective cohort studies. Whether transvaginal ultrasound (TVS) is used for primary evaluation or for evaluation after vasa previa is suspected on transabdominal scan, TVS with color Doppler is the superior method for evaluation. Transvaginal color Doppler in the second trimester resulted in 100% sensitivity and 99.0 to 99.8% sensitivity.
Prediction of early onset and late onset pregnancy induced hypertension (PIH) based on 3-D placental volume and uterine artery Doppler (UtA Doppler)
Increased uterine artery resistance and small placental volume as measured by 3-D ultrasound placental volume at 11 to 13 weeks is associated with the development of early PIH but is not associated with the development of late onset PIH. In early onset PIH both neonatal weight and placental weight were lower, while there was no difference in the late onset PIH group and unaffected pregnancies, suggesting that early and late PIH may be different entities.
Combined maternal characteristics and fetal biometry were used to predict SGA at 30-34 weeks. In the absence of preeclampsia (PE), maternal characteristics associated with SGA included increased inter-pregnancy interval, decreased height and weight, certain racial origins, cigarette smokers, prior history of SGA and chronic hypertension. In the absence of PE, the Z-scores* of head circumference (HC), abdominal circumference (AC), femur length (FL) or estimated fetal weight (EFW) were reduced at 30 to 34 weeks gestation. Using these criteria, 80% of SGA neonates at <10th percentile delivering at preterm with SGA were identified with a false positive rate of 10%.
*z Score: A z-score (aka, a standard score) indicates how many standard deviations an element is from the mean. A z-score can be calculated from the following formula. z = (X – μ) / σ where z is the z-score, X is the value of the element, μ is the population mean, and σ is the standard deviation.
The same methodology is used in the study to predict SGA neonates at 35-37 weeks. Similar maternal characteristics were noted at 35-37 weeks and combined with fetal biometry (EFW Z-scores), 90% of pregnancies were identified that delivered a SGA neonate within 2 weeks of assessment with a false positive rate of 10%. In addition, 70% of SGA neonates were predicted that delivered at ≥ 37 weeks.
Longitudinal assessment of lung area measurements in isolated left sided congenital diaphragmatic hernia (CDH). 
Two-dimensional (2D) ultrasound was used for fetal right lung measurements between 19 and 37 weeks in healthy fetuses and those with isolated left-sided CDH. Right lung areas were measured by tracing and longest diameter methods and thereafter a lung area-to-head circumference ratio (LHR) was calculated. Compared to healthy fetuses, those with CDH demonstrated a significantly slower increase in right lung areas and LHR. Severe forms of CDH showed less growth in right lung areas and LHR compared to milder forms of CHD and neonatal death was associated with no growth in right lung measurements.
Above: Ebstein anomaly with displacement of the tricuspid valve, atrialized right ventricle (ARV) and functional right ventricle (FRV); RA= large right atrium, LV=left ventricle, RV=right ventricle.
Above: Tricuspid valve dysplasia. No displacement of the TV (tricuspid valve); RA= large right atrium, LV=left ventricle, RV=right ventricle.
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