Early anatomy ultrasound in women at increased risk of fetal anomalies

Can Ultrasound in Early Gestation Improve Visualization of Fetal Cardiac Structures in Obese Pregnant Women?

OBJECTIVES

To determine whether ultrasound (US) imaging of obese pregnant women in early gestation improves fetal cardiac visualization.

METHODS

We report a prospective longitudinal trial comparing late first- and early second-trimester US to traditional second-trimester US for fetal cardiac screening in maternal obesity. All study participants received US for fetal cardiac screening at a gestational age of 13 weeks to 15 weeks 6 days using a transvaginal or transabdominal approach (UST1). All patients also underwent a traditional transabdominal examination at 20 to 22 weeks (UST2). If UST2 failed to complete the cardiac visualization, a follow up examination (second UST2) was performed 2 to 4 weeks later. Imaging was considered complete if the visceral situs, 4 chambers, outflow tracts, and 3 vessels were visualized. The completion rates between UST1 and UST2 were the primary outcomes. A power analysis (85%) and sample size calculation (n = 145) were performed.

RESULTS

A total of 152 pregnancies met study criteria. Completion rates of cardiac screening were 77% for UST1 and 70% for UST2 (P = .143). This comparison reached statistical significance in patients with a body mass index of greater than 40 kg/m² (UST1 [69%] versus UST2 [38%]; P = .001). Sixty-two percent of patients with a body mass index of greater than 40 kg/m² required second UST2. The highest fetal cardiac screening completion rate was achieved when UST1 was combined with UST2 (96.1%). In 1 fetus, congenital heart disease was detected at UST1 and later confirmed.

CONCLUSIONS

This study represents the largest prospective trial assessing early-gestation US for fetal cardiac screening in the setting of maternal obesity. In obese pregnancies, the addition of early-gestation US to the 20- to 22-week US substantially improves the visualization of fetal cardiac anatomy.

Does transvaginal ultrasound at 13-15 weeks improve anatomic survey completion rates in obese gravidas?

Objective: Obesity increases the difficulty of completing the fetal anatomic survey. This is of added concern in obese gravidas who are at higher risk of congenital fetal anomalies. We hypothesized that incorporation of an early transvaginal assessment could improve the completion rate of the fetal anatomic survey in obese women.Methods: We performed a prospective, longitudinal, blinded study of obese gravidas (BMI ≥ 35 kg/m²) comparing the use of a single early second trimester transvaginal ultrasound in addition to midtrimester transabdominal ultrasound versus traditional serial midtrimester ultrasound alone for completion of the anatomic survey. Transvaginal ultrasound for anatomy was performed between 13 0/7 and 15 6/7 week followed by midtrimester anatomic ultrasound, with each patient serving as her own control. Structures were marked as optimally or suboptimally viewed after each ultrasound. Sonographers and reviewers were blinded to images from the transvaginal ultrasound. Completion rates and gestational age at completion were compared between groups.Results: Fifty subjects were included. Fetal anatomic survey was completed in 62% using standard midtrimester assessment versus 78% with the addition of early transvaginal assessment (p = .04). The survey was completed at an earlier gestational age utilizing the transvaginal approach (22 0/7 ± 6 3/7) compared to traditional midtrimester transabdominal ultrasound approach (25 2/7 ± 5 3/7) p < .0005.Conclusions: Incorporation of an early transvaginal assessment of anatomy in obese women improved the rate of completion and led to earlier gestational age at completion of the fetal anatomic survey. Consideration should be given to including an early transvaginal sonogram as part of routine assessment of women with a BMI ≥ 35.

The Role of Early Gestation Ultrasound in the Assessment of Fetal Anatomy in Maternal Obesity

OBJECTIVES

The 2012 Eunice Kennedy Shriver National Institute of Child Health fetal imaging consensus suggested that fetal anatomy ultrasound in obese pregnancies be performed at 20 to 22 weeks, with follow-up in 2 to 4 weeks if anatomy is incomplete. It was postulated that imaging in early gestation may improve visualization, although no prospective trials had been done to date.

METHODS

We performed a prospective longitudinal blinded trial comparing an early gestation ultrasound (13 + 0 to 15 + 6 weeks) with the traditional second-trimester ultrasound for completion of the fetal anatomy survey in obese patients. Inclusion criteria included singleton gestation, body mass index (BMI) more than 30, less than 16 + 0 weeks' gestation, and no karyotype abnormality; exclusion criteria included age younger than 18 years, more than 16 weeks' gestation at time of consent, and BMI less than 30. Participants received a transvaginal and/or transabdominal sonogram for fetal anatomic survey at 13 + 0 to 15 + 6 weeks' gestation (US1). Images from US1 were blinded to physicians and sonographers performing subsequent examinations. All participants underwent the traditional transabdominal sonogram at 18 to 24 weeks (US2). If US2 failed to complete the anatomic survey, a repeat transabdominal sonogram (2-US2) was performed 2 to 4 weeks later.

RESULTS

A total of 152 pregnancies met the criteria. Anatomy completion rate was 57.2% for US1 and 62.5% for US2, which was not statistically significant, even when stratified by BMI. Excluding the philtrum, the US1 performed better than US2 for class III obesity (65.5% versus 45.5% [P = .035]). Combination of US1 + US2 yielded a higher completion rate than US2 + 2-US2 (94.1% versus 83.6% [P = .0023]).

CONCLUSIONS

In the setting of maternal obesity, the addition of an ultrasound in early gestation may be of highest benefit for patients with class III obesity (BMI > 40 kg/m² ).

Imaging of congenital Zika virus infection: the route to identification of prognostic factors

Zika virus (ZIKV) has recently emerged as a novel teratogenic agent associated with severe neurological complications. The risk associated with maternal infection remains to be exactly defined but appears to be significant. Like other TORCH agents (toxoplasmosis, other agents, rubella, cytomegalovirus and herpes simplex), it is unlikely that all affected fetuses will be symptomatic at birth. It is therefore urgent to better define the spectrum of anomalies observed in infected fetuses to provide adequate parental counseling. In this review, we provide a comprehensive analysis of major cases described to date and highlight specific prenatal and postnatal radiological findings of congenital ZIKV infection. A total of 19 reports were included in our analysis. ZIKV seemed to harbor a specific tropism for the central nervous system, and anomalies were mostly limited to the brain. Major radiological findings were ventriculomegaly, diffuse calcifications and signs of abnormal gyration as well as cortical development. In addition, a significant number of fetuses suffered from intra uterine growth restriction. Based on these findings, we provide recommendations for adequate radiological monitoring of at-risk pregnancies. © 2016 John Wiley & Sons, Ltd.

The Performance of First-Trimester Anatomy Scan: A Decision Analysis

Introduction First-trimester ultrasound (US) for anatomy assessment may improve anomaly detection, but it may also increase overall US utilization. We sought to assess the utility of first-trimester US for evaluation of fetal anatomy. Materials and Methods A decision analytic model was created to compare first- plus second-trimester anatomy scans to second-trimester scan alone in four populations: general, normal weight women, obese women, and diabetics. Probability estimates were obtained from the literature. Outcomes considered were number of: major structural anomalies detected, US performed, and false-positive US. Multivariable sensitivity analyses were performed to evaluate the consistency of the model with varying assumptions. Results A strategy of first- plus second-trimester US detected the highest number of anomalies but required more US examinations per anomaly detected. The addition of a first-trimester anatomy US was associated with a small increase in the false-positive US (< 10/10,000). In populations with higher anomaly prevalence and lower second-trimester US sensitivity (i.e., diabetes, obesity), the number of additional US performed per anomaly detected with the first-trimester US was < 60. Discussion In high-risk populations, a first-trimester US in addition to a second-trimester US may be a beneficial approach to detecting anomalies.

Sonographic detection of central nervous system defects in the first trimester of pregnancy

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first-trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first-trimester findings. This review summarizes the current knowledge of first-trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

Fetal diagnostic indications for second and third trimester outpatient pregnancy termination

OBJECTIVE

To determine the frequency of diagnostic indications among women seeking to terminate pregnancies for reasons of fetal abnormality, spontaneous fetal demise, or a genetic disorder in a private outpatient clinic specializing in late outpatient abortion procedures.

METHOD

A total of 1005 women requested termination of pregnancy for reasons of genetic disorder, fetal anomaly, or fetal demise over 20 years (1992-2012). Gestational ages ranged from 12 to 39 weeks. In all cases, a documented diagnosis of fetal abnormality or fetal demise was made prior to referral. Records were reviewed to verify fetal diagnosis for all patients seeking termination of pregnancy for reasons of fetal disorder. Major complications included major unintended surgery, hemorrhage requiring transfusion, or pelvic infection.

RESULTS

Preoperative diagnoses included the following: chromosomal abnormalities (n = 378), genetic syndromes and single gene disorders (n = 30), structural anomalies (n = 494), and other conditions (n = 103). These include 26 cases of spontaneous fetal demise and nine selective terminations of one abnormal twin. The major complication rate was 0.5%.

CONCLUSIONS

The majority of diagnoses were in the categories of genetic disorder and neurologic abnormality.