Society for Maternal-Fetal Medicine Consult Series #72: Twin-twin transfusion syndrome and twin anemia-polycythemia sequence.

30% of spontaneously occurring twins are monozygotic, of which two-thirds are monochorionic, possessing a single placenta. A common placental mass with shared inter-twin placental circulation is key to the development and management of complications unique to monochorionic gestations. In this Consult, we review general considerations and a contemporary approach to twin-twin transfusion syndrome and twin anemia polycythemia sequence, providing management recommendations based on the available evidence. The following are Society for Maternal-Fetal Medicine recommendations: (1) we recommend routine first trimester sonographic determination of chorionicity and amnionicity (GRADE 1B); (2) we recommend that ultrasound surveillance for twin-twin transfusion syndrome begin at 16 weeks of gestation for all monochorionic-diamniotic twin pregnancies and continue at least every 2 weeks until delivery, with more frequent monitoring indicated with clinical concern (GRADE 1C); (3) we recommend that routine sonographic surveillance for twin-twin transfusion syndrome minimally include assessment of amniotic fluid volumes on both sides of the inter-twin membrane and evaluation for the presence or absence of urine-filled fetal bladders, and ideally incorporate Doppler study of the umbilical arteries (GRADE 1C); (4) we recommend fetoscopic laser surgery as the standard treatment for stage II through stage IV twin-twin transfusion syndrome presenting between 16 and 26 weeks of gestation (GRADE 1A); (5) we recommend expectant management with at least weekly fetal surveillance for asymptomatic patients continuing pregnancies complicated by stage I twin-twin transfusion syndrome, and consideration for fetoscopic laser surgery for stage I twin-twin transfusion syndrome presentations between 16 and 26 weeks of gestation complicated by additional factors such as maternal polyhydramnios-associated symptomatology (GRADE 1B); (6) we recommend an individualized approach to laser surgery for early- and late-presenting twin-twin transfusion syndrome (GRADE 1C); (7) we recommend that all patients with twin-twin transfusion syndrome qualifying for laser therapy be referred to a fetal intervention center for further evaluation, consultation, and care (Best Practice); (8) after laser therapy, we suggest weekly surveillance for 6 weeks followed by resumption of every-other-week surveillance thereafter, unless concern exists for post-laser twin-twin transfusion syndrome, post-laser twin anemia polycythemia sequence, or fetal growth restriction (GRADE 2C); (9) following the resolution of twin-twin transfusion syndrome after fetoscopic laser surgery, and without other indications for earlier delivery, we recommend delivery of dual-surviving monochorionic-diamniotic twins at 34 to 36 weeks of gestation (GRADE 1C); (10) in twin-twin transfusion syndrome pregnancies complicated by post-treatment single fetal demise, we recommend full-term delivery (39 weeks) of the surviving co-twin to avoid complications of prematurity unless indications for earlier delivery exist (GRADE 1C); (11) we recommend that fetoscopic laser surgery should not influence the mode of delivery (Best Practice); (12) we recommend that prenatal diagnosis of twin anemia polycythemia sequence minimally requires either middle cerebral artery Doppler peak systolic velocity values >1.5 multiples of the median and <1.0 multiples of the median in donor and recipient twins, respectively, or an inter-twin Δ middle cerebral artery peak systolic velocity >0.5 multiples of the median (GRADE 1C); (13) we recommend that providers consider incorporating middle cerebral artery Doppler peak systolic velocity determinations into all monochorionic twin ultrasound surveillance beginning at 16 weeks of gestation (GRADE 1C); (14) consultation with a specialized fetal care center is recommended when twin anemia polycythemia sequence progresses to a more advanced disease stage (≥ stage II) prior to 32 weeks of gestation or when concern arises for co-existing complications such as twin-twin transfusion syndrome (Best Practice).

Fetal cardiac screening: 1st trimester and beyond.

Congenital heart defects (CHD) are the most common birth defect and a leading cause of infant morbidity and mortality. CHD often occurs in low-risk pregnant patients, which underscores the importance of routine fetal cardiac screening at the time of the 2nd trimester ultrasound. Prenatal diagnosis of CHD is important for counseling and decision-making, focused diagnostic testing, and optimal perinatal and delivery management. As a result, prenatal diagnosis has led to improved neonatal and infant outcomes. Updated fetal cardiac screening guidelines, coupled with technological advancements and educational efforts, have resulted in increased prenatal detection of CHD in both low- and high-risk populations. However, room for improvement remains. In recent years, fetal cardiac screening for specific high-risk populations has started in the 1st trimester, which is a trend that is likely to expand over time. This review discusses fetal cardiac screening throughout pregnancy.

Management of fetal head and neck masses: Evaluation of prenatal factors associated with airway obstruction and decision for definitive airway and ex-utero intrapartum treatment at birth.

OBJECTIVE: Fetal head and neck masses can result in critical airway obstruction. Our study aimed to evaluate prenatal factors associated with the decision for a definitive airway, including ex-utero intrapartum treatment (EXIT), at birth among at-risk fetuses. METHODS: A single-institution retrospective review evaluated all fetal head and neck masses prenatally diagnosed from 2005 to 2023. The primary outcome was the decision for a definitive airway at birth, including intubation, tracheostomy, or EXIT. RESULTS: Thirty four patients were included, with 23 deliveries occurring at our institution. 8/23 (35%) patients received a definitive airway at birth, six underwent an EXIT procedure, and two required intubation only. Patients who received a definitive airway had higher rates of polyhydramnios (50% vs. 7%, p = 0.03), tracheal narrowing on ultrasound (US) (50% vs. 0%, p = 0.01), tracheal displacement on US (63% vs. 0%, p < 0.01), abnormal fetal breathing on US (50% vs. 0%, p = 0.01), tracheal narrowing or displacement on magnetic resonance imaging (MRI) (75% vs. 7%, p < 0.01), and larger mass maximum diameter (7.9 vs. 4.3 cm, p = 0.02). In our series, 100% of patients with polyhydramnios, tracheal narrowing or displacement on either US or MRI, and abnormal fetal breathing on US received a definitive airway at birth. CONCLUSION: Prenatal findings of tracheal narrowing or displacement, polyhydramnios, and abnormal fetal breathing are strongly associated with the decision for a definitive airway at birth and warrant mobilization of appropriate resources.

Obstetric Inpatient and Ultrasound Clinical Personnel Absences during the COVID-19 Pandemic in New York City.

OBJECTIVE: To review obstetric personnel absences at a hospital during the initial peak of coronavirus disease 2019 (COVID-19) infection risk in New York City from March 25 to April 21, 2020. STUDY DESIGN: This retrospective study evaluated absences at Morgan Stanley Children's Hospital. Clinical absences for (1) Columbia University ultrasonographers, (2) inpatient nurses, (3) labor and delivery operating room (OR) technicians, (4) inpatient obstetric nurse assistants, and (5) attending physicians providing inpatient obstetric services were analyzed. Causes of absences were analyzed and classified as illness, vacation and holidays, leave, and other causes. Categorical variables were compared with the chi-square test or Fisher's exact test. RESULTS: For nurses, absences accounted for 1,052 nursing workdays in 2020 (17.2% of all workdays) compared with 670 (11.1%) workdays in 2019 (p < 0.01). Significant differentials in days absent in 2020 compared with 2019 were present for (1) postpartum nurses (21.9% compared with 12.9%, p < 0.01), (2) labor and delivery nurses (14.8% compared with 10.6%, p < 0.01), and (3) antepartum nurses (10.2% compared with 7.4%, p = 0.03). Evaluating nursing assistants, 24.3% of workdays were missed in 2020 compared with 17.4% in 2019 (p < 0.01). For ultrasonographers, there were 146 absences (25.2% of workdays) in 2020 compared with 96 absences (16.0% of workdays) in 2019 (p < 0.01). The proportion of workdays missed by OR technicians was 22.6% in 2020 and 18.3% in 2019 (p = 0.25). Evaluating attending physician absences, a total of 78 workdays were missed due to documented COVID-19 infection. Evaluating the causes of absences, illness increased significantly between 2019 and 2020 for nursing assistants (42.6 vs. 57.4%, p = 0.02), OR technicians (17.1 vs. 55.9%, p < 0.01), and nurses (15.5 vs. 33.7%, p < 0.01). CONCLUSION: COVID-19 outbreak surge planning represents a major operational issue for medical specialties such as critical care due to increased clinical volume. Findings from this analysis suggest it is prudent to devise backup staffing plans. KEY POINTS: · 1) COVID-19 outbreak surge planning represents a major operational issue for obstetrics.. · 2) Inpatient obstetric volume cannot be reduced.. · 3) Staffing contingencies plans for nurses, sonographers, and physicians may be required..

Special Report of the Society for Maternal-Fetal Medicine Placenta Accreta Spectrum Ultrasound Marker Task Force: Consensus on definition of markers and approach to the ultrasound examination in pregnancies at risk for placenta accreta spectrum.

Placenta accreta spectrum includes the full range of abnormal placental attachment to the uterus or other structures, encompassing placenta accreta, placenta increta, placenta percreta, morbidly adherent placenta, and invasive placentation. The incidence of placenta accreta spectrum has increased in recent years, largely driven by increasing rates of cesarean delivery. Prenatal detection of placenta accreta spectrum is primarily made by ultrasound and is important to reduce maternal morbidity associated with the condition. Despite a large body of research on various placenta accreta spectrum ultrasound markers and their screening performance, inconsistencies in the literature persist. In response to the need for standardizing the definitions of placenta accreta spectrum markers and the approach to the ultrasound examination, the Society for Maternal-Fetal Medicine convened a task force with representatives from the American Institute of Ultrasound in Medicine, the American College of Obstetricians and Gynecologists, the American College of Radiology, the International Society of Ultrasound in Obstetrics and Gynecology, the Society for Radiologists in Ultrasound, the American Registry for Diagnostic Medical Sonography, and the Gottesfeld-Hohler Memorial Ultrasound Foundation. The goals of the task force were to assess placenta accreta spectrum sonographic markers on the basis of available data and expert consensus, provide a standardized approach to the prenatal ultrasound evaluation of the uterus and placenta in pregnancies at risk of placenta accreta spectrum, and identify research gaps in the field. This manuscript provides information on the Placenta Accreta Spectrum Task Force process and findings.

The role of fetal echocardiogram after detection of extracardiac anomalies in utero (fetal echocardiogram for extracardiac malformations).

OBJECTIVE: We aimed to investigate the utility of comprehensive screening fetal echocardiography (FE) for patients diagnosed with any type of fetal extracardiac malformation (ECM) at a single multidisciplinary fetal center. METHODS: We retrospectively reviewed all patients presenting to our referral center for FE due to a prenatal diagnosis of ECM (January 2013-December 2018). RESULTS: Among 641 patients with ≥1 ECM referred for FE, 78 (12.2%) had CHD diagnosed at 25.6 ± 0.5 weeks. The frequency of CHD by type of ECM ranged from 35.1% for craniofacial to 9.8% for thoracic. Increasing number of fetal ECMs was strongly associated with CHD: odds ratio 2.01 (95% confidence interval: 1.06-3.69) for two ECMs, 9.57 (2.00-49.05) for three ECMs, and 11.68 (3.84-37.15) for more than three ECMs. Of fetuses with ECM and an abnormal genetic finding, 33.3% had CHD as compared to 10.9% of those without (p < 0.0001). Obstetric anatomy sonogram detected 43.6% of CHD. CONCLUSION: CHD was commonly diagnosed among fetuses with any type of ECM at our center but was not always detected on obstetric sonogram. As the presence of CHD may impact decision-making and perinatal care, patients with a diagnosis of any fetal ECM should be considered for FE.

Clinical and Demographic Risk Factors for COVID-19 during Delivery Hospitalizations in New York City.

OBJECTIVE: This study was aimed to review 4 weeks of universal novel coronavirus disease 2019 (COVID-19) screening among delivery hospitalizations, at two hospitals in March and April 2020 in New York City, to compare outcomes between patients based on COVID-19 status and to determine whether demographic risk factors and symptoms predicted screening positive for COVID-19. STUDY DESIGN: This retrospective cohort study evaluated all patients admitted for delivery from March 22 to April 18, 2020, at two New York City hospitals. Obstetrical and neonatal outcomes were collected. The relationship between COVID-19 and demographic, clinical, and maternal and neonatal outcome data was evaluated. Demographic data included the number of COVID-19 cases ascertained by ZIP code of residence. Adjusted logistic regression models were performed to determine predictability of demographic risk factors for COVID-19. RESULTS: Of 454 women delivered, 79 (17%) had COVID-19. Of those, 27.9% (n = 22) had symptoms such as cough (13.9%), fever (10.1%), chest pain (5.1%), and myalgia (5.1%). While women with COVID-19 were more likely to live in the ZIP codes quartile with the most cases (47 vs. 41%) and less likely to live in the ZIP code quartile with the fewest cases (6 vs. 14%), these comparisons were not statistically significant (p = 0.18). Women with COVID-19 were less likely to have a vaginal delivery (55.2 vs. 51.9%, p = 0.04) and had a significantly longer postpartum length of stay with cesarean (2.00 vs. 2.67days, p < 0.01). COVID-19 was associated with higher risk for diagnoses of chorioamnionitis and pneumonia and fevers without a focal diagnosis. In adjusted analyses, including demographic factors, logistic regression demonstrated a c-statistic of 0.71 (95% confidence interval [CI]: 0.69, 0.80). CONCLUSION: COVID-19 symptoms were present in a minority of COVID-19-positive women admitted for delivery. Significant differences in obstetrical outcomes were found. While demographic risk factors demonstrated acceptable discrimination, risk prediction does not capture a significant portion of COVID-19-positive patients. KEY POINTS: · COVID-19 symptoms were present in a minority of COVID-19-positive women admitted.. · COVID-19 symptomatology did not appear to differ before or after the apex of infection in New York.. · Demographic risk factors are unlikely to capture a significant portion of COVID-19-positive patients..

A Survey of Labor and Delivery Practices in New York City during the COVID-19 Pandemic.

Recently, a novel coronavirus, precisely severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), that causes the disease novel coronavirus disease 2019 (COVID-19) has been declared a worldwide pandemic. Over a million cases have been confirmed in the United States. As of May 5, 2020, New York State has had over 300,000 cases and 24,000 deaths with more than half of the cases and deaths occurring in New York City (NYC). Little is known, however, of how this virus impacts pregnancy. Given this lack of data and the risk for severe disease in this relatively immunocompromised population, further understanding of the obstetrical management of COVID-19, as well as hospital level preparation for its control, is crucial. Guidance has come from expert opinion, professional societies and public health agencies, but to date, there is no report on how obstetrical practices have adapted these recommendations to their local situations. We therefore developed an internet-based survey to elucidate the practices put into place to guide the care of obstetrical patients during the COVID-19 pandemic. We surveyed obstetrical leaders in four academic medical centers in NYC who were implementing and testing protocols at the height of the pandemic. We found that all sites made changes to their practices, and that there appeared to be agreement with screening and testing for COVID-19, as well as labor and delivery protocols, for SARS-CoV-2-positive patients. We found less consensus with respect to inpatient antepartum fetal surveillance. We hope that this experience is useful to other centers as they formulate their plans to face this pandemic. KEY POINTS: · Practices changed to accommodate public health needs.. · Most practices are screened for novel COVID-19 on admission.. · Fetal testing in COVID-19 patients varied..

Telehealth for High-Risk Pregnancies in the Setting of the COVID-19 Pandemic.

As New York City became an international epicenter of the novel coronavirus disease 2019 (COVID-19) pandemic, telehealth was rapidly integrated into prenatal care at Columbia University Irving Medical Center, an academic hospital system in Manhattan. Goals of implementation were to consolidate in-person prenatal screening, surveillance, and examinations into fewer in-person visits while maintaining patient access to ongoing antenatal care and subspecialty consultations via telehealth virtual visits. The rationale for this change was to minimize patient travel and thus risk for COVID-19 exposure. Because a large portion of obstetric patients had underlying medical or fetal conditions placing them at increased risk for adverse outcomes, prenatal care telehealth regimens were tailored for increased surveillance and/or counseling. Based on the incorporation of telehealth into prenatal care for high-risk patients, specific recommendations are made for the following conditions, clinical scenarios, and services: (1) hypertensive disorders of pregnancy including preeclampsia, gestational hypertension, and chronic hypertension; (2) pregestational and gestational diabetes mellitus; (3) maternal cardiovascular disease; (4) maternal neurologic conditions; (5) history of preterm birth and poor obstetrical history including prior stillbirth; (6) fetal conditions such as intrauterine growth restriction, congenital anomalies, and multiple gestations including monochorionic placentation; (7) genetic counseling; (8) mental health services; (9) obstetric anesthesia consultations; and (10) postpartum care. While telehealth virtual visits do not fully replace in-person encounters during prenatal care, they do offer a means of reducing potential patient and provider exposure to COVID-19 while providing consolidated in-person testing and services. KEY POINTS: · Telehealth for prenatal care is feasible.. · Telehealth may reduce coronavirus exposure during prenatal care.. · Telehealth should be tailored for high risk prenatal patients..

Telehealth Uptake into Prenatal Care and Provider Attitudes during the COVID-19 Pandemic in New York City: A Quantitative and Qualitative Analysis.

OBJECTIVE: This study aimed to (1) determine to what degree prenatal care was able to be transitioned to telehealth at prenatal practices associated with two affiliated hospitals in New York City during the novel coronavirus disease 2019 (COVID-19) pandemic and (2) describe providers' experience with this transition. STUDY DESIGN: Trends in whether prenatal care visits were conducted in-person or via telehealth were analyzed by week for a 5-week period from March 9 to April 12 at Columbia University Irving Medical Center (CUIMC)-affiliated prenatal practices in New York City during the COVID-19 pandemic. Visits were analyzed for maternal-fetal medicine (MFM) and general obstetrical faculty practices, as well as a clinic system serving patients with public insurance. The proportion of visits that were telehealth was analyzed by visit type by week. A survey and semistructured interviews of providers were conducted evaluating resources and obstacles in the uptake of telehealth. RESULTS: During the study period, there were 4,248 visits, of which approximately one-third were performed by telehealth (n = 1,352, 31.8%). By the fifth week, 56.1% of generalist visits, 61.5% of MFM visits, and 41.5% of clinic visits were performed via telehealth. A total of 36 providers completed the survey and 11 were interviewed. Accessing technology and performing visits, documentation, and follow-up using the telehealth electronic medical record were all viewed favorably by providers. In transitioning to telehealth, operational challenges were more significant for health clinics than for MFM and generalist faculty practices with patients receiving public insurance experiencing greater difficulties and barriers to care. Additional resources on the patient and operational level were required to optimize attendance at in-person and video visits for clinic patients. CONCLUSION: Telehealth was rapidly implemented in the setting of the COVID-19 pandemic and was viewed favorably by providers. Limited barriers to care were observed for practices serving patients with commercial insurance. However, to optimize access for patients with Medicaid, additional patient-level and operational supports were required. KEY POINTS: · Telehealth uptake differed based on insurance.. · Medicaid patients may require increased assistance for telehealth.. · Quick adoption of telehealth is feasible..

Fetal Diagnosis and Therapy during the COVID-19 Pandemic: Guidance on Behalf of the International Fetal Medicine and Surgery Society.

The COVID-19 pandemic has stressed patients and healthcare givers alike and challenged our practice of antenatal care, including fetal diagnosis and therapy. This document aims to review relevant recent information to allow us to optimize prenatal care delivery. We discuss potential modifications to obstetric management and fetal procedures in SARS-CoV2-negative and SARS-CoV2-positive patients with fetal anomalies or disorders. Most fetal therapies are time sensitive and cannot be delayed. If personnel and resources are available, we should continue to offer procedures of proven benefit, acknowledging any fetal and maternal risks, including those to health care workers. There is, to date, minimal, unconfirmed evidence of spontaneous vertical transmission, though it may theoretically be increased with some procedures. Knowing a mother's preoperative SARS-CoV-2 status would enable us to avoid or defer certain procedures while she is contagious and to protect health care workers appropriately. Some fetal conditions may alternatively be managed neonatally. Counseling regarding fetal interventions which have a possibility of additional intra- or postoperative morbidity must be performed in the context of local resource availability. Procedures of unproven benefit should not be offered. We encourage participation in registries and trials that may help us to understand the impact of COVID-19 on pregnant women, their fetuses, and neonates.

Obstetric and gynecologic ultrasound curriculum and competency assessment in residency training programs: consensus report.

Ultrasound imaging has become integral to the practice of obstetrics and gynecology. With increasing educational demands and limited hours in residency programs, dedicated time for training and achieving competency in ultrasound has diminished substantially. The American Institute of Ultrasound in Medicine assembled a multisociety task force to develop a consensus-based, standardized curriculum and competency assessment tools for obstetric and gynecologic ultrasound training in residency programs. The curriculum and competency assessment tools were developed based on existing national and international guidelines for the performance of obstetric and gynecologic ultrasound examinations and thus are intended to represent the minimum requirement for such training. By expert consensus, the curriculum was developed for each year of training, criteria for each competency assessment image were generated, the pass score was established at, or close to, 75% for each, and obtaining a set of 5 ultrasound images with pass score in each was deemed necessary for attaining each competency. Given the current lack of substantial data on competency assessment in ultrasound training, the task force expects that the criteria set forth in this document will evolve with time. The task force also encourages use of ultrasound simulation in residency training and expects that simulation will play a significant part in the curriculum and the competency assessment process. Incorporating this training curriculum and the competency assessment tools may promote consistency in training and competency assessment, thus enhancing the performance and diagnostic accuracy of ultrasound examination in obstetrics and gynecology.

A study to assess global availability of fetal surgery for myelomeningocele.

AIM: To establish the provision of fetal surgery for myelomeningocele (MMC) worldwide. METHODS: Through the International Society for Prenatal Diagnosis (ISPD) Fetal Therapy Special Interest Group and the North American Fetal Therapy Network (NAFTNet), fetal therapy centres were surveyed (September 2017-June 2018) regarding availability of fetal MMC surgical repair, patient inclusion criteria, repair techniques, number of cases, and outcome reporting. Responses were summarised on an interactive map on the ISPD website. RESULTS: Forty-four of 59 centres responded (74.6%) of which 34 centres (77.1%) currently offered fetal surgery for MMC and seven centres (15.9%) were awaiting a first case after service set up. Patient inclusion criteria were similar and based on the Management of Myelomeningocele (MOMS) trial. Five centres (14.7%) operated beyond 26 weeks' gestational age, outside the MOMS criteria. Open fetal surgery was provided in 23 centres (67.6%), fetoscopic surgery only in five (14.7%), and six centres offered both types (17.6%). Neurosurgical closure was similar for open surgery but highly variable in fetoscopy surgery. The median number of cases per centre was 21 (range 1-253). CONCLUSIONS: Fetal surgery for MMC is now offered globally. Two thirds of centres offer open repair via hysterotomy using criteria based on the MOMS trial.

Obstetric and Gynecologic Ultrasound Curriculum and Competency Assessment in Residency Training Programs: Consensus Report.

Ultrasound imaging has become integral to the practice of obstetrics and gynecology. With increasing educational demands and limited hours in residency programs, dedicated time for training and achieving competency in ultrasound has diminished substantially. The American Institute of Ultrasound in Medicine assembled a multisociety task force to develop a consensus-based, standardized curriculum and competency assessment tools for obstetric and gynecologic ultrasound training in residency programs. The curriculum and competency assessment tools were developed based on existing national and international guidelines for the performance of obstetric and gynecologic ultrasound examinations and thus are intended to represent the minimum requirement for such training. By expert consensus, the curriculum was developed for each year of training, criteria for each competency assessment image were generated, the pass score was established at, or close to, 75% for each, and obtaining a set of 5 ultrasound images with pass score in each was deemed necessary for attaining each competency. Given the current lack of substantial data on competency assessment in ultrasound training, the task force expects that the criteria set forth in this document will evolve with time. The task force also encourages use of ultrasound simulation in residency training and expects that simulation will play a significant part in the curriculum and the competency assessment process. Incorporating this training curriculum and the competency assessment tools may promote consistency in training and competency assessment, thus enhancing the performance and diagnostic accuracy of ultrasound examination in obstetrics and gynecology.

Advances in ultrasound imaging for congenital malformations during early gestation.

BACKGROUND: With refinement in ultrasound technology, detection of fetal structural abnormalities has improved and there have been detailed reports of the natural history and expected outcomes for many anomalies. The ability to either reassure a high-risk woman with normal intrauterine images or offer comprehensive counseling and offer options in cases of strongly suspected lethal or major malformations has shifted prenatal diagnoses to the earliest possible gestational age. METHODS: When indicated, scans in early gestation are valuable in accurate gestational dating. Stricter sonographic criteria for early nonviability guard against unnecessary intervention. Most birth defects are without known risk factors, and detection of certain malformations is possible in the late first trimester. RESULTS: The best time for a standard complete fetal and placental scan is 18 to 20 weeks. In addition, certain soft anatomic markers provide clues to chromosomal aneuploidy risk. Maternal obesity and multifetal pregnancies are now more common and further limit early gestation visibility. CONCLUSION: Other advanced imaging techniques during early gestation in select cases of suspected malformations include fetal echocardiography and magnetic resonance imaging.

Do Doppler studies enhance surveillance of uncomplicated monochorionic diamniotic twins?

OBJECTIVES: To determine whether isolated abnormal Doppler indices before 28 weeks predict adverse pregnancy outcomes in uncomplicated monochorionic diamniotic (MCDA) twins. METHODS: A retrospective cohort study of MCDA twin pregnancies receiving antenatal testing at a single center between 2007 and 2013 was conducted. Sonographic surveillance, including Doppler velocimetric studies of the umbilical artery, ductus venosus, and middle cerebral artery of each twin, was initiated by 28 weeks and repeated at least every 2 weeks. All pregnancies were deemed "uncomplicated" at initial sonography, without evidence of polyhydramnios, oligohydramnios, intrauterine growth restriction, twin growth discordance of at least 20%, structural or chromosomal anomalies, or unclear chorionicity. Pregnancies were divided into 2 groups: those with isolated Doppler abnormalities before 28 weeks and those with normal Doppler indices. The primary outcome was a composite including twin-twin transfusion syndrome, intrauterine growth restriction of more than 1 twin, growth discordance of at least 20%, preterm delivery before 34 weeks for fetal indications, or demise of more than 1 fetus. RESULTS: Ninety-six patients were included, with 22 (22.9%) having isolated Doppler abnormalities before 28 weeks. The incidence of the primary outcome did not differ between groups (36.4% versus 28.4%; P = .47). The abnormal Doppler group underwent a greater number of sonographic examinations (15 versus 10; P= .001) and more antenatal admissions for fetal concerns (50.0% versus 12.2%; P < .001). CONCLUSIONS: Isolated Doppler abnormalities are commonly encountered in uncomplicated MCDA pregnancies before 28 weeks yet are not clearly predictive of twin-specific complications. Doppler abnormalities were associated with increased sonographic surveillance and antenatal hospitalizations, suggesting an influence on physician practice patterns. Data may not support Doppler studies before 28 weeks for routine MCDA twin monitoring.

Gastroschisis: incidence and prediction of growth restriction.

AIMS: Fetuses with gastroschisis are at increased risk of intrauterine growth restriction (IUGR). However, there is a tendency for underestimation of fetal abdominal circumference and hence fetal weight, leading to overdiagnosis of IUGR. Our objective was to evaluate the accuracy of ultrasound for the prediction of being small for gestational age (SGA) at birth in these cases. METHODS: A retrospective study of prenatally diagnosed cases of gastroschisis was conducted at a tertiary center. Fetal weight was estimated using the formula of Hadlock. IUGR was defined as an estimated fetal weight ≤10th percentile for gestational age. SGA at the time of birth was defined as a birth weight ≤10th percentile for gestational age. The incidence of IUGR on last ultrasound and that of SGA at birth were calculated, and the precision of ultrasound in predicting SGA was determined. RESULTS: IUGR was reported on the last ultrasound prior to delivery in 9/25 cases (36%). Postnatally, 13/25 newborns (52%) were SGA. All sonographically suspected cases of IUGR based on the last ultrasound were SGA at birth. The positive predictive value of the last ultrasound in identifying SGA was 100%. CONCLUSIONS: At least half of the infants affected by gastroschisis were SGA at birth. Sonographic estimation of fetal weight within 1 month of birth reliably predicted SGA in infants with gastroschisis.