Influence of maternal BMI on genetic sonography in the FaSTER trial

Challenges of prenatal diagnosis in obese pregnant women

Obesity rates are increasing world-wide with most of the increase in women of the reproductive age group. While recognised as an important contributor to non-communicable diseases, pregnant women with obesity are particularly at risk of not only maternal and pregnant complications but also have an increased risk of congenital malformations. Furthermore, pregnant obese women are more likely to be older and therefore at a greater risk of aneuploidy. Prenatal diagnosis in these women especially those who are morbidly obese is challenging due not only to their weight but the implications of the increase adiposity on biochemical markers of aneuploidy. In this review we discuss the current challenges in providing prenatal diagnosis for these women including those related to the ergonomics of ultrasound and those inherent in them because of their obesity. Appropriate counselling for these women should include the lower sensitivity of the tests, the difficulties in performing some of the procedures (imaging and invasive testing) as well as the increased risk of structural abnormalities related to their obesity.

Obesity in prenatal medicine: a game changer?

Obesity is recognized by the World Health Organization (WHO) as a disease in its own right. Moreover, obesity is an increasingly concerning public health issue across the world and its prevalence is rising amongst women of reproductive age. The fertility of over-weight and obese women is reduced and they experience a higher rate of miscarriage. In pregnant women obesity not only increases the risk of antenatal complications, such as preeclampsia and gestational diabetes, but also fetal abnormalities, and consequently the overall feto-maternal mortality. Ultrasound is one of the most valuable methods to predict and evaluate pregnancy complications. However, in overweight and obese pregnant women, the ultrasound examination is met with several challenges, mainly due to an impaired acoustic window. Overall obesity in pregnancy poses special challenges and constraints to the antenatal care and increases the rate of pregnancy complications, as well as complications later in life for the mother and child.

Impact of maternal body mass index on the accuracy of third trimester sonographic estimation of fetal weight

OBJECTIVES

To Determine whether maternal body mass index (BMI) can affect the accuracy of sonographic estimation of fetal weight (EFW) in the third trimester when compared to neonatal birthweight (BW).

METHODS

Secondary analysis from our original prospective cohort of pregnant women beyond 34 weeks, distributed in 4 groups according to their BMI: normal, overweight, obese and morbid obese. Fetal biometry and fluid measurements were obtained by two experienced sonographers, blinded for patient's clinical information and to each other's measurements. Average EFW and neonatal BW were converted into gestational-specific Z-scores. Interobserver correlation coefficient (ICC) and Cronbach's reliability coefficient (CRC) were calculated. Bland-Altman (BA) plots were constructed to assess the level of accuracy.

RESULTS

100 women were enrolled (800 measurements obtained by 17 sonographers): 17 had normal BMI (17%), 27 were overweight (27%), 29 were obese (29%) and 27 were morbidly obese (27%). There was no statistical difference for GA at delivery (p = 0.74), EFW (p = 0.05) or BW (p = 0.09) between groups (Table 1). Mean Z-score for EFW was - 0.17 (SD 0.81) and for neonatal BW was - 0.25 (SD 0.74). ICC was 0.69 (95% CI 0.57, 0.78) and CRC was 0.82. Mean Z-score difference was small (Table 2). When stratifying according to BMI categories, the ICC ranged from 0.49 to 0.76. Reliability indices ranged from 0.66 to 0.86. The Z-scores' differences were overall small with no statistical difference (Table 3). BA showed evenly distributed interobserver differences (Fig. 1).

CONCLUSIONS

When performed by trained sonographers, fetal weight estimation in the third trimester is accurate when compared to neonatal birthweight at increasing BMI categories.

Obstetric Outcomes in Singleton Pregnancies with Abnormal Placental Cord Insertions

OBJECTIVE

There is wide variation in the management of pregnancies complicated by abnormal placental cord insertion (PCI), which includes velamentous cord insertion (VCI) and marginal cord insertion (MCI). We tested the hypothesis that abnormal PCI is associated with small for gestational age (SGA) infants.

STUDY DESIGN

This is a retrospective cohort study of all pregnant patients undergoing anatomic ultrasound at a single institution from 2010 to 2017. Patients with abnormal PCI were matched in a 1:2 ratio by race, parity, gestational age at the time of ultrasound, and obesity to patients with normal PCIs. The primary outcome was SGA at delivery. Secondary outcomes were cesarean delivery, preterm delivery, cesarean delivery for nonreassuring fetal status, 5-minute Apgar score < 7, umbilical artery pH < 7.1, and neonatal intensive care unit admission. These outcomes were compared using univariate and bivariate analyses.

RESULTS

Abnormal PCI was associated with an increased risk of SGA (relative risk [RR]: 2.43; 95% confidence interval [CI]: 1.26-4.69), increased risk of preterm delivery <37 weeks (RR: 3.60; 95% CI: 1.74-7.46), and <34 weeks (RR: 3.50; 95% CI: 1.05-11.63) compared with patients with normal PCI. There was no difference in rates of cesarean delivery, Apgar score of <7 at 5 minutes, acidemia, or neonatal intensive care unit admission between normal and abnormal PCI groups. In a stratified analysis, the association between abnormal PCI and SGA did not differ by the type of abnormal PCI (p for interaction = 0.46).

CONCLUSION

Abnormal PCI is associated with an increased risk of SGA and preterm delivery. These results suggest that serial fetal growth assessments in this population may be warranted.

KEY POINTS

· Abnormal PCI is associated with SGA infants and preterm birth.. · If an abnormal PCI is identified, the provider should consider serial growth ultrasounds.. · There is no difference in obstetric outcomes between VCI and MCI..

A Matter of Time: Does Gestational Age Affect the Duration of the Fetal Anatomic Survey?

OBJECTIVE

To assess the average duration of detailed fetal anatomic surveys in pregnancy in relation to gestational age (GA) and the maternal body mass index (BMI) to determine optimal timing of the examination.

METHODS

This was a retrospective cohort study of gravidae presenting for detailed fetal anatomic examinations between January 1, 2010, and June 30, 2017. After excluding examinations expected to have longer duration (ie, multifetal, major fetal anomalies), there were a total of 6522 examinations performed between GAs of 18 weeks 0 days and 22 weeks 0 days. Women were grouped by BMI, and results were analyzed by logistic regression.

RESULTS

Gravidae of normal weight (BMI, 18.5-24.9 kg/m² ) had a decrease of 47.47 seconds of the examination time with each increasing week of gestation (P = .036). Overweight (BMI, 25-29.9 kg/m² ) gravidae similarly had a decrease of 66.31 seconds of the examination time with each additional week of gestation (P = .017). Underweight (BMI, 8.5 kg/m² ) and obese (BMI, ≥30 kg/m² ) gravidae did not have differences in the examination time with increasing GA. Increases in suboptimal examinations were noted with an increasing BMI (P < .001). There was a decreased frequency of suboptimal examinations in obese gravidae with a BMI of 40 kg/m² or higher with increasing GA (P = .037).

CONCLUSIONS

The duration of detailed fetal anatomic examinations decreased with increasing GA in normal-weight and overweight gravidae but not in obese gravidae. Performing the anatomy scan earlier in class I and II obese gravidae (BMI, 30-40 kg/m² ) may enable improved pregnancy management options without increasing the examination duration or likelihood of a suboptimal evaluation.

Obesity in Pregnancy: ACOG Practice Bulletin, Number 230

Obstetrician-gynecologists are the leading experts in the health care of women, and obesity is the most common medical condition in women of reproductive age. Obesity in women is such a common condition that the implications relative to pregnancy often are unrecognized, overlooked, or ignored because of the lack of specific evidence-based treatment options. The management of obesity requires long-term approaches ranging from population-based public health and economic initiatives to individual nutritional, behavioral, or surgical interventions. Therefore, an understanding of the management of obesity during pregnancy is essential, and management should begin before pregnancy and continue through the postpartum period. Although the care of the obese woman during pregnancy requires the involvement of the obstetrician or other obstetric care professional, additional health care professionals, such as nutritionists, can offer specific expertise related to management depending on the comfort level of the obstetric care professional. The purpose of this Practice Bulletin is to offer an integrated approach to the management of obesity in women of reproductive age who are planning a pregnancy.

ACR Appropriateness Criteria® Second and Third Trimester Screening for Fetal Anomaly

The Appropriateness Criteria for the imaging screening of second and third trimester fetuses for anomalies are presented for fetuses that are low risk, high risk, have had soft markers detected on ultrasound, and have had major anomalies detected on ultrasound. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Ultrasound for the Pregnant Person With Diabesity

Diabetes and obesity increase the risk of congenital anomalies, but the putative mechanisms of this increased risk are not fully elucidated. In this chapter, we delve into sonographic characteristics associated with diabetes and obesity, including fetal structural anomalies, functional cardiac alterations, and growth abnormalities. We will also discuss the technical challenges of imaging in the patient with diabesity and propose methodologies for optimizing imaging. Lastly, we will address the prevention of workplace-associated musculoskeletal disorders injury for sonographers.

Screening for Aneuploidy in the Patient With Diabesity: Pearls and Pitfalls

The American College of Obstetrics & Gynecology (ACOG) recommends offering aneuploidy screening to all pregnant women. Obesity and diabetes are not associated with an increased risk of aneuploidy; however, they can complicate and compromise testing options. As the prevalence of obesity and diabetes, or "diabesity" increases, counseling women regarding potential limitations in testing performance of aneuploidy screening is of paramount importance. This chapter reviews options for aneuploidy screening for women with diabesity including sonography/nuchal translucency, serum analyte screening, and cell-free DNA. Potential challenges associated with diagnostic testing with amniocentesis and chorionic villus sampling in women with obesity are also discussed.

Impact of maternal obesity on fetal cardiac screening: which follow-up strategy is cost-effective?

OBJECTIVE

To perform a cost-effectiveness analysis of different follow-up strategies for non-obese and obese women who had incomplete fetal cardiac screening for major congenital heart disease (CHD).

METHODS

Three decision-analytic models, one each for non-obese, obese and Class-III-obese women, were developed to compare five follow-up strategies for initial suboptimal fetal cardiac screening. The five strategies were: (1) no follow-up ultrasound (US) examination but direct referral to fetal echocardiography (FE); (2) one follow-up US, then FE if fetal cardiac views were still suboptimal; (3) up to two follow-up US, then FE if fetal cardiac views were still suboptimal; (4) one follow-up US and no FE; and (5) up to two follow-up US and no FE. The models were designed to identify fetuses with major CHD in a theoretical cohort of 4 000 000 births in the USA. Outcomes related to neonatal mortality and neurodevelopmental disability were evaluated. A cost-effectiveness willingness-to-pay threshold was set at US$100 000 per quality-adjusted life year (QALY). Base-case and sensitivity analysis and Monte-Carlo simulation were performed.

RESULTS

In our base-case models for all body mass index (BMI) groups, no follow-up US, but direct referral to FE led to the best outcomes, detecting 7%, 25% and 82% more fetuses with CHD in non-obese, obese and Class-III-obese women, respectively, compared with the baseline strategy of one follow-up US and no FE. However, no follow-up US, but direct referral to FE was above the US$100 000/QALY threshold and therefore not cost-effective. The cost-effective strategy for all BMI groups was one follow-up US and no FE. Both up to two follow-up US with no FE and up to two follow-up US with FE were dominated (being more costly and less effective), while one follow-up US with FE was over the cost-effectiveness threshold. One follow-up US and no FE was the optimal strategy in 97%, 93% and 86% of trials in Monte-Carlo simulation for non-obese, obese and Class-III-obese models, respectively.

CONCLUSION

For both non-obese and obese women with incomplete fetal cardiac screening, the optimal CHD follow-up screening strategy is no further US and immediate referral to FE; however, this strategy is not cost-effective. Considering costs, one follow-up US and no FE is the preferred strategy. For both obese and non-obese women, Monte-Carlo simulations showed clearly that one follow-up US and no FE was the optimal strategy. Both non-obese and obese women with initial incomplete cardiac screening examination should therefore be offered one follow-up US. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Guideline No. 391-Pregnancy and Maternal Obesity Part 1: Pre-conception and Prenatal Care

OBJECTIVE

This guideline will review key aspects in the pregnancy care of women with obesity. Part I will focus on pre-conception and pregnancy care. Part II will focus on team planning for delivery and Postpartum Care.

INTENDED USERS

All health care providers (obstetricians, family doctors, midwives, nurses, anaesthesiologists) who provide pregnancy-related care to women with obesity.

TARGET POPULATION

Women with obesity who are pregnant or planning pregnancies.

EVIDENCE

Literature was retrieved through searches of Statistics Canada, Medline, and The Cochrane Library on the impact of obesity in pregnancy on antepartum and intrapartum care, maternal morbidity and mortality, obstetrical anaesthesia, and perinatal morbidity and mortality. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2018. Grey (unpublished) literature was identified through searching the websites of health technology assessment and related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the authors. Then the Maternal-Fetal Medicine Committee peer reviewed the content and submitted comments for consideration, and the Board of the Society of Obstetricians and Gynaecologists of Canada (SOGC) approved the final draft for publication. Areas of disagreement were discussed during meetings, at which time consensus was reached. The level of evidence and quality of the recommendation made were described using the Evaluation of Evidence criteria of the Canadian Task Force on Preventive Health Care.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in these guidelines may increase obstetrical provider recognition of the issues affected pregnant individuals with obesity, including clinical prevention strategies, communication between the health care team, the patient and family as well as equipment and human resource planning. It is hoped that regional, provincial and federal agencies will assist in the education and support of coordinated care for pregnant individuals with obesity.

GUIDELINE UPDATE

SOGC guidelines will be automatically reviewed 5 years after publication. However, authors can propose another review date if they feel that 5 years is too short/long based on their expert knowledge of the subject matter.

SPONSORS

This guideline was developed with resources funded by the SOGC.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Decreasing Accuracy of the eFAST Examination—Another Challenge Due to Morbid Obesity

The extended focused assessment with sonography for trauma (eFAST) ultrasound examination is an essential step in the initial assessment of trauma patients. Its accuracy depends on the ability to acquire high-quality ultrasound images, and we hypothesized that increasing BMI was associated with increased odds for incorrect eFAST. All adult blunt trauma activations at a high-volume urban trauma center in 2016 that underwent eFAST and CT chest, abdomen, and pelvis were included (n = 446). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the eFAST were calculated with CT results as reference. The association of BMI and eFAST accuracy was determined using univariate analyses. Sensitivity and specificity of the eFASTexamination were 27.1 per cent and 91.7 per cent, respectively, with an overall 76.2 per cent accuracy. At BMI 36 kg/m2, the odds of having incorrect eFAST results increased to odds ratio (OR) = 1.85 (95% confidence interval, 1.03–3.32; P = 0.05). For those with BMI > 40 kg/m2, the OR increased to OR = 3.12 (95% confidence interval, 1.45–6.69; P = 0.01). One-third of patients in this study were obese or morbidly obese. The latter was associated with increased odds for incorrect eFAST results, particularly the abdominal examination component.

Detailed Fetal Anatomic Ultrasound Examination Duration and Association With Body Mass Index

OBJECTIVE

To evaluate the association of the duration of the detailed fetal anatomic ultrasound examination with maternal body mass.

METHODS

This was a retrospective chart review of patients presenting to our clinic for detailed fetal anatomic examinations between January 1, 2010, and June 30, 2017. After excluding multifetal pregnancies and other examinations expected to have a longer duration, a total of 6,522 examinations were performed between 18 0/7 and 22 0/7 weeks of gestation. Results were analyzed using analysis of variance and Student's t-test.

RESULTS

Mean (SD) body mass index (BMI) was 29.3 (±7.7), and mean examination time was 51.5 (±10.4) minutes. We found that mean examination time was 48.8 (±9.6) minutes for patients with normal BMIs, 50.6 (±10.0) minutes for overweight patients, 52.2 (±10.4) minutes for patients with class I obesity, 54.6 (±10.3) minutes for patients with class II obesity, and 57.7 (±10.3) minutes for patients with class III obesity (P<.001). The duration of the detailed fetal anatomic ultrasound examination increased continuously with BMI (r=0.285, P<.001).

CONCLUSION

We found that the duration of detailed fetal anatomic examinations increased with BMI. Examinations for gravid patients with class III obesity lasted 8.9 minutes longer than those for gravid patients with normal BMIs; examinations for gravid patients with BMIs of 50 or higher lasted 13.5 minutes longer. This information may be useful for fetal ultrasound examination scheduling.

Pregnancy in Women with Obesity

Pregnancy in women with obesity is an important public health problem with short- and long-term implications for maternal and child health. Obesity complicates almost all aspects of pregnancy. Given the growing prevalence of obesity in women, obstetric providers need to understand the risks associated with obesity in pregnancy and the unique aspects of management for women with obesity. Empathic and patient-centered care, along with knowledge, can optimize outcomes for women and children.

The mediating effects of gestational diabetes on fetal growth and adiposity in women who are overweight and obese: secondary analysis of the LIMIT randomised trial

OBJECTIVE

To describe the mediating effect of maternal gestational diabetes on fetal biometry and adiposity measures among overweight or obese pregnant women.

DESIGN

Secondary analysis of the LIMIT randomised trial.

SETTING

Public hospitals, metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with body mass index (BMI) ≥25 kg/m² and singleton gestation.

METHODS

Fetal ultrasound measures at 36 weeks of gestation and baseline BMI from women randomised to the LIMIT trial Standard Care group (n = 912 women) were used to conduct causal mediation analyses using regression-based methods.

MAIN OUTCOMES MEASURES

Ultrasound measures of fetal biometry and adiposity at 36 weeks of gestation.

RESULTS

Increased maternal BMI was associated with increased measures of fetal head circumference [direct (unmediated) effect 0.18 (95% CI: 0.05-0.31), P = 0.005; total effect 0.17 (95% CI: 0.02-0.31), P = 0.018], abdominal circumference [direct effect 0.26 (95% CI: 0.11-0.41), P = 0.001; total effect 0.26 (95% CI: 0.11-0.42), P = 0.001] and estimated fetal weight [direct effect 0.22 (95% CI: 0.08-0.35), P = 0.002; total effect 0.22 (95% CI: 0.08-0.35), P = 0.002], with no evidence of mediation by treated gestational diabetes. There was no apparent association between maternal BMI and fetal adiposity measures, or mediation by treated gestational diabetes.

CONCLUSIONS

We show an important association between increased maternal BMI and fetal growth, not mediated by treated gestational diabetes. There was no association between increased maternal BMI and fetal adiposity measures, or mediation by treated gestational diabetes. Whether these findings represent 'saturation' in the effect of maternal BMI on fetal growth or the effect of treatment of GDM is unclear.

FUNDING

This project was funded by a 4-year project grant from the National Health and Medical Research Council (NHMRC), Australia (ID 519240); The Channel 7 Children's Research Foundation, South Australia; and the US National Institutes of Health (R01 HL094235-01).

TWEETABLE ABSTRACT

Increased fetal growth associated with maternal obesity is not mediated by gestational diabetes.

Maternal Body Mass Index and Amniotic Fluid Index in Late Gestation

OBJECTIVES

To determine the effect, if any, of an increasing maternal body mass index (BMI) on sonographically diagnosed oligohydramnios in late gestation and how it subsequently affects obstetric and neonatal outcomes.

METHODS

This retrospective cohort study evaluated all women with singleton gestations who had a sonographic examination at 40 to 42 weeks' gestational age at North Shore University Hospital from 2010 through 2013. Underweight women (prepregnancy BMI < 18.5 kg/m² ) were excluded because of higher rates of oligohydramnios and fetal growth restriction. Patients were classified into 5 groups by late-pregnancy BMI. The primary variable of interest was the diagnosis of oligohydramnios (amniotic fluid index < 5 cm). Secondary variables of interest included the mode of delivery and indication for primary cesarean delivery. A multivariable logistic regression analysis was performed.

RESULTS

Oligohydramnios was identified in 189 of 1671 patients (11.3%). There was no significant difference in the amniotic fluid index between BMI groups. The rate of primary cesarean delivery increased with each successive BMI group (P < .001) such that women in the class III obesity group had an approximately 3-fold higher rate of primary cesarean delivery than women in the normal BMI group and a 2-fold higher rate than women in the overweight BMI group. In the final multivariable logistic regression model, a high BMI, nulliparity, and excessive gestational weight gain were associated with primary cesarean delivery. However, oligohydramnios did not contribute significantly to the model.

CONCLUSIONS

The maternal BMI is not associated with oligohydramnios in late gestation. An increasing maternal BMI significantly increases the risk of primary cesarean delivery.

Obesity in Pregnancy: Optimizing Outcomes for Mom and Baby

Obesity is common in women of childbearing age, and management of this population around the time of pregnancy involves specific challenges. Weight and medical comorbidities should be optimized both before and during pregnancy. During pregnancy, gestational weight gain should be limited, comorbidities should be appropriately screened for and managed, and fetal health should be monitored. Consideration should be given to the optimal timing of delivery and to reducing surgical and anesthetic complications. In the postpartum period, breastfeeding and weight loss should be promoted. Maternal obesity is associated with adverse metabolic effects in offspring, promoting an intergenerational cycle of obesity.

Third trimester ultrasound accuracy and delivery outcome in obese and morbid obese pregnant women

OBJECTIVE

Several studies have highlighted the negative impact of maternal obesity on ultrasound accuracy for fetal weight estimation (EFW). However, the evidence is conflicting. We aimed in our study to find if the ultrasound accuracy for EFW would differ or decrease in obese and morbid obesity classes. We also studied the mode of delivery within the same cohort.

METHODS

It is a retrospective study of obese patients with recorded BMI ≥30 kg/m², class I and II (BMI: 30-39.9 kg/m²) compared with extreme obese class III (BMI ≥40 kg/m²), who gave birth after 28-week gestation of viable singleton, who had an ultrasound within 7 d of delivery with reported normal amniotic fluid and no major fetal anomaly; the EFW was consistently measured through Hadlock regression formula in the period of 2014-2015 inclusive. Differences between the EFW and actual birth weight (ABW) were assessed by percentage error, accuracy in predictions within ±10% of error and the Pearson correlation coefficient were used to correlate EFW with the ABW. The study's secondary outcome was to study the mode of delivery and the rate of cesarean section in obese and morbid obese patients.

RESULTS

Total 106 cases fulfilled our criteria. Class I and II as the first group (n = 53). Class III as the second group (n = 53). Maternal and birth characteristics were similar. The Pearson correlation coefficient equal 1 in both groups. The overall mean absolute difference (MAD) in grams of the whole obese cohort was 242 ± 213. The MAD was 242 ± 202 and 242 ± 226 g for the first and second group, respectively (p = 1.0). The overall mean absolute percentage error (MAPE) in this obese cohort was 8%. The MAPE for the first and second group, respectively were 8 and 7% (p = 0.4). The overall rate of cesarean delivery was 60% (64/106) with no differences between the obese and morbid obese BMI classes. Sixty-six percentage (42/64) of these cesarean cases was for repeat cesarean section.

CONCLUSION

Despite what has been previously reported about the negative impact of maternal obesity on EFW accuracy, we could not demonstrate this relationship in our obese cohort (MAPE <10%). In addition, we could not illustrate a significant difference in ultrasound accuracy across various obesity classes. However, we found a significantly increased rate of delivery by repeated cesarean section in this obese cohort.

First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome.

SEARCH METHODS

We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies.

SELECTION CRITERIA

Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more.

AUTHORS' CONCLUSIONS

Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.

First and second trimester serum tests with and without first trimester ultrasound tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three copies of chromosome 21 (or the specific area of chromosome 21 implicated in causing Down's syndrome) rather than two. It is the commonest congenital cause of mental disability. Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.  Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal) and false negative screening tests (i.e. a fetus with Down's syndrome will be missed). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

To estimate and compare the accuracy of first and second trimester serum markers with and without first trimester ultrasound markers for the detection of Down's syndrome in the antenatal period, as combinations of markers.

SEARCH METHODS

We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), the Database of Abstracts of Reviews of Effectiveness (the Cochrane Library 25 August 2011), MEDION (25 August 2011), the Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), the National Research Register (Archived 2007), and Health Services Research Projects in Progress database (25 August 2011). We did not apply a diagnostic test search filter. We did forward citation searching in ISI citation indices, Google Scholar and PubMed 'related articles'. We also searched reference lists of retrieved articles SELECTION CRITERIA: Studies evaluating tests of combining first and second trimester maternal serum markers in women up to 24 weeks of gestation for Down's syndrome, with or without first trimester ultrasound markers, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

Twenty-two studies (reported in 25 publications) involving 228,615 pregnancies (including 1067 with Down's syndrome) were included. Studies were generally high quality, although differential verification was common with invasive testing of only high risk pregnancies. Ten studies made direct comparisons between tests. Thirty-two different test combinations were evaluated formed from combinations of eight different tests and maternal age; first trimester nuchal translucency (NT) and the serum markers AFP, uE3, total hCG, free βhCG, Inhibin A, PAPP-A and ADAM 12. We looked at tests combining first and second trimester markers with or without ultrasound as complete tests, and we also examined stepwise and contingent strategies.Meta-analysis of the six most frequently evaluated test combinations showed that a test strategy involving maternal age and a combination of first trimester NT and PAPP-A, and second trimester total hCG, uE3, AFP and Inhibin A significantly outperformed other test combinations that involved only one serum marker or NT in the first trimester, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate. However, the evidence was limited in terms of the number of studies evaluating this strategy, and we therefore cannot recommend one single screening strategy.

AUTHORS' CONCLUSIONS

Tests involving first trimester ultrasound with first and second trimester serum markers in combination with maternal age are significantly better than those without ultrasound, or those evaluating first trimester ultrasound in combination with second trimester serum markers, without first trimester serum markers. We cannot make recommendations about a specific strategy on the basis of the small number of studies available.

Are First Trimester Nuchal Septations Independent Risk Factors for Chromosomal Anomalies?

OBJECTIVES

There is conflicting information regarding the role of nuchal septations during first-trimester genetic screening. This study was designed to determine whether nuchal septations are risk factors for chromosomal anomalies, independent of increased nuchal translucency (NT), in the first trimester of pregnancy.

METHODS

This retrospective cohort study included all women who underwent first-trimester genetic screening between November 2011 and December 2014. The 95th percentile for the NT measurement was calculated for each gestational week. A multivariable logistic regression analysis was performed to determine whether the visualization of nuchal septations was an independent risk factor for chromosomal analysis while controlling for confounding variables. P < .05 was considered significant.

RESULTS

Chromosomal abnormalities were present in 1.0% of the population (33 of 3275). The prevalence of chromosomal abnormalities was significantly higher among fetuses with nuchal septations compared to fetuses with normal NT without septations (P < .001) and those with NT above the 95th percentile without septations (P < .001). The sonographic evidence of septations was associated with high risk of chromosomal abnormalities (odds ratio, 40.0; 95% confidence interval, 9.1-174.0) after controlling for NT measurements and other confounding variables.

CONCLUSIONS

Visualization of nuchal septations during first-trimester genetic screening is a powerful risk factor for chromosomal anomalies, independent of increased NT.

Antenatal dietary and lifestyle advice for women who are overweight or obese and the effect on fetal growth and adiposity: the LIMIT randomised trial

OBJECTIVE

To report the influence of maternal overweight and obesity on fetal growth and adiposity and effects of an antenatal dietary and lifestyle intervention among these women on measures of fetal growth and adiposity as secondary outcomes of the LIMIT Trial.

DESIGN

Randomised controlled trial.

SETTING

Public maternity hospitals in metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with a body mass index ≥ 25 kg/m(2), and singleton gestation between 10(+0) and 20(+0) weeks.

METHODS

Women were randomised to Lifestyle Advice or continued Standard Care and offered two research ultrasound scans at 28 and 36 weeks of gestation.

MAIN OUTCOME MEASURES

Ultrasound measures of fetal growth and adiposity.

RESULTS

For each fetal body composition parameter, mean Z-scores were substantially higher when compared with population standards. Fetuses of women receiving Lifestyle Advice demonstrated significantly greater mean mid-thigh fat mass, when compared with fetuses of women receiving Standard Care (adjusted difference in means 0.17; 95% CI 0.02-0.32; P = 0.0245). While subscapular fat mass increased between 28 and 36 weeks of gestation in fetuses in both treatment groups, the rate of adipose tissue deposition slowed among fetuses of women receiving Lifestyle Advice, when compared with fetuses of women receiving Standard Care (P = 0.0160). No other significant differences were observed.

CONCLUSIONS

These findings provide the first evidence of changes to fetal growth following an antenatal dietary and lifestyle intervention among women who are overweight or obese.

Antepartum Care of the Obese Patient

In the United States, roughly half of women are either overweight (24.5%) or obese (21.4%) when they become pregnant. Women who are obese before pregnancy are at increased risk for a number of pregnancy complications relative to normal-weight women. Specifically, obesity is associated with significantly increased maternal risks, including gestational diabetes mellitus, hypertensive disorders of pregnancy, and sleep disordered breathing. Maternal obesity is also associated with increased risks of adverse fetal outcomes, including prematurity, stillbirth, congenital anomalies, and abnormal fetal growth. In this review, we will discuss the implications of obesity with respect to antepartum care.

What Is the Rate of Incomplete Fetal Anatomic Surveys During a Second-Trimester Scan? Retrospective Observational Study of 4000 Nonobese Pregnant Women

OBJECTIVES

The purpose of this study was to estimate the rate of incomplete fetal anatomic surveys during a second-trimester scan due to an unfavorable fetal position in a nonobese population.

METHODS

All pregnant women who came to the Altamedica Fetal-Maternal Medical Center, a specialized center for prenatal diagnosis, for a routine second-trimester scan between January 2012 and April 2013 were retrospectively included in the analysis. Patients with a body mass index higher than 30.0 kg/m(2) or anterior fibroids larger than 5 cm were not included in the study.

RESULTS

Of 4000 pregnant women admitted for a second-trimester scan, 169 (4.2%) came back within 2 weeks to complete the examination because of an unfavorable fetal position. In particular, 104 (2.6%) needed visualization of only 1 view, and 65 (1.6%) needed more than 1 view. The most difficult organ to visualize was the corpus callosum, in 73 cases (1.8%); the face was not visualized in 69 cases (1.7%); the cerebellar vermis was not seen in 47 fetuses (1.1%); and the heart could not be completely examined in 40 fetuses (1.0%). Of the 4000 women, 169 (4.2%) had a nonexhaustive scan; 149 (3.7%) needed a second scan to complete the second-trimester survey; 14 (0.35%) needed a third scan; and 2 (0.05%) remained with a not completely exhaustive scan.

CONCLUSIONS

There is always a small percentage of incomplete fetal anatomic surveys during a second-trimester scan, which cannot be modified by the sonographer's skill or by technical sonographic innovations.

First trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Noninvasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. However, no test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

The aim of this review was to estimate and compare the accuracy of first trimester serum markers for the detection of Down's syndrome in the antenatal period, both as individual markers and as combinations of markers. Accuracy is described by the proportion of fetuses with Down's syndrome detected by screening before birth (sensitivity or detection rate) and the proportion of women with a low risk (normal) screening test result who subsequently had a baby unaffected by Down's syndrome (specificity).

SEARCH METHODS

We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 25 August 2011), MEDION (25 August 2011), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), The National Research Register (Archived 2007), Health Services Research Projects in Progress database (25 August 2011). We did forward citation searching ISI citation indices, Google Scholar and PubMed 'related articles'. We did not apply a diagnostic test search filter. We also searched reference lists and published review articles.  

SELECTION CRITERIA

We included studies in which all women from a given population had one or more index test(s) compared to a reference standard (either chromosomal verification or macroscopic postnatal inspection). Both consecutive series and diagnostic case-control study designs were included. Randomised trials where individuals were randomised to different screening strategies and all verified using a reference standard were also eligible for inclusion. Studies in which test strategies were compared head-to-head either in the same women, or between randomised groups were identified for inclusion in separate comparisons of test strategies. We excluded studies if they included less than five Down's syndrome cases, or more than 20% of participants were not followed up.

DATA COLLECTION AND ANALYSIS

We extracted data as test positive or test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria. We used hierarchical summary ROC meta-analytical methods or random-effects logistic regression methods to analyse test performance and compare test accuracy as appropriate. Analyses of studies allowing direct and indirect comparisons between tests were undertaken.

MAIN RESULTS

We included 56 studies (reported in 68 publications) involving 204,759 pregnancies (including 2113 with Down's syndrome). Studies were generally of good quality, although differential verification was common with invasive testing of only high-risk pregnancies. We evaluated 78 test combinations formed from combinations of 18 different tests, with or without maternal age; ADAM12 (a disintegrin and metalloprotease), AFP (alpha-fetoprotein), inhibin, PAPP-A (pregnancy-associated plasma protein A, ITA (invasive trophoblast antigen), free βhCG (beta human chorionic gonadotrophin), PlGF (placental growth factor), SP1 (Schwangerschafts protein 1), total hCG, progesterone, uE3 (unconjugated oestriol), GHBP (growth hormone binding protein), PGH (placental growth hormone), hyperglycosylated hCG, ProMBP (proform of eosinophil major basic protein), hPL (human placental lactogen), (free αhCG, and free ßhCG to AFP ratio. Direct comparisons between two or more tests were made in 27 studies.Meta-analysis of the nine best performing or frequently evaluated test combinations showed that a test strategy involving maternal age and a double marker combination of PAPP-A and free ßhCG significantly outperformed the individual markers (with or without maternal age) detecting about seven out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). Limited evidence suggested that marker combinations involving PAPP-A may be more sensitive than those without PAPP-A.

AUTHORS' CONCLUSIONS

Tests involving two markers in combination with maternal age, specifically PAPP-A, free βhCG and maternal age are significantly better than those involving single markers with and without age. They detect seven out of 10 Down's affected pregnancies for a fixed 5% FPR. The addition of further markers (triple tests) has not been shown to be statistically superior; the studies included are small with limited power to detect a difference.The screening blood tests themselves have no adverse effects for the woman, over and above the risks of a routine blood test. However some women who have a 'high risk' screening test result, and are given amniocentesis or chorionic villus sampling (CVS) have a risk of miscarrying a baby unaffected by Down's. Parents will need to weigh up this risk when deciding whether or not to have an amniocentesis or CVS following a 'high risk' screening test result.

The multidisciplinary approach to the care of the obese parturient

Maternal obesity in pregnancy is associated with increased maternal and fetal risks. Pregnancy management should include counseling, screening, and optimization of maternal health, increased fetal surveillance, and preparation for parturition. A multidisciplinary approach should be implemented including collaboration from obstetricians, nutritionists, anesthesiologists, social workers, and neonatologists to optimize perinatal outcomes. Pregnancy is an ideal window of opportunity to influence both the patient's long-term health and the health of the offspring.

Fetal imaging: executive summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging (MRI) in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and MRI in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost effectiveness, and to identify research opportunities. This article is the executive summary of the workshop.

Increasing maternal body mass index and the accuracy of sonographic estimation of fetal weight near delivery

OBJECTIVES

To evaluate whether an increasing body mass index (BMI) influences the accuracy of sonographic estimation of fetal weight.

METHODS

We performed a retrospective cohort study of singleton deliveries over a 2-year period in a single institution. Patients were included if they had a fetal weight estimation within 2 weeks of delivery. The Δ estimated fetal weight (EFW) was calculated by subtracting the sonographic EFW from the birth weight and compared among our study groups, which were based on the maternal BMI class. We also compared the absolute percentage error of estimation, rate of substantial error greater than 20%, rate of underestimation, and ability to predict fetal weight greater than 4000 g. Post hoc power analysis determined that our study group of 1200 patients allowed for an α of .05 and β of .90.

RESULTS

We included 1177 women in our analysis. The median ΔEFW varied between study groups: 137, 202, 157, 200, and 189 g, respectively, in normal-weight, overweight, and obese classes 1, 2, and 3 (P = .01). The median percentage error of estimation between study groups varied between 5.0% in normal-weight women and 7.1% in class 2 obese women (P= .05). The rate of substantial error was similar between study groups and varied between 2.7% in class 1 obese women and 4.3% in normal-weight and class 2 obese women. Linear regression analysis showed a weak association between maternal BMI and ΔEFW (R(2) = 0.005; r = 0.069).

CONCLUSIONS

The absolute ΔEFW was lower in normal-weight women; however, the percentage error of the EFW was similar between women of varying BMI classifications, as was the rate of substantial error and the rate of underestimation of the EFW.

Obesity and the challenges of ultrasound fetal abnormality diagnosis

Prenatal ultrasound has become an essential clinical tool for aneuploidy screening, detection of fetal congenital anomalies, and assessment of fetal growth and well-being. Maternal obesity, an increasing global problem, has been shown to decrease the accuracy of ultrasound examination in high-risk pregnancy. The purpose of this review is to provide an evidenced-based perspective on the challenges of performing fetal ultrasound in obese women and to provide a practical guide on how to care for these patients in the ultrasound suite.

Early second-trimester sonography to improve the fetal anatomic survey in obese patients

OBJECTIVES

Fetal anatomic surveys are difficult to perform on obese patients. However, there are limited data available on methods to improve the rate of complete anatomy scans in these patients. The objective of this study was to determine whether the addition of an early second-trimester fetal anatomy scan improves the rate of complete anatomy scans in obese patients.

METHODS

We conducted a prospective cohort study of 100 obese patients at a city hospital who were scheduled for a fetal anatomy scan using transvaginal and transabdominal sonography at 14 to 16 weeks (early anatomy scan) and an anatomy scan at 18 to 22 weeks ("routine" anatomy scan). Inclusion criteria were a body mass index of 30 kg/m(2) or higher, singleton pregnancy, and presentation for prenatal care before 16 weeks. Data for the routine anatomy scan alone versus a combination of early and routine anatomy scans was calculated by the McNemar χ(2) test for categorical variables and the Wilcoxon signed ranks test for continuous variables.

RESULTS

The addition of the early anatomy scan significantly increased the rate of complete anatomy scans from 42% to 51% (P < .01). It also significantly improved visualization of the head, thorax, and abdomen and significantly increased the mean number of items seen (P < .05).

CONCLUSIONS

The addition of an early second-trimester fetal anatomy scan to a routine anatomy scan performed later in the second trimester significantly improves the rate of complete anatomy scans in obese patients.

Limitations of Aneuploidy and Anomaly Detection in the Obese Patient

Obesity is a worldwide epidemic and can have a profound effect on pregnancy risks. Obese patients tend to be older and are at increased risk for structural fetal anomalies and aneuploidy, making screening options critically important for these women. Failure rates for first-trimester nuchal translucency (NT) screening increase with obesity, while the ability to detect soft-markers declines, limiting ultrasound-based screening options. Obesity also decreases the chances of completing the anatomy survey and increases the residual risk of undetected anomalies. Additionally, non-invasive prenatal testing (NIPT) is less likely to provide an informative result in obese patients. Understanding the limitations and diagnostic accuracy of aneuploidy and anomaly screening in obese patients can help guide clinicians in counseling patients on the screening options.

Super obesity in pregnancy: difficulties in clinical management

As the obesity pandemic continues in the United States, obesity in pregnancy has become an area of interest. Many studies focus on women with body mass index (BMI) ⩾ 30 kg m(-2). Unfortunately, the prevalence of patients with BMI ⩾ 50 kg m(-2) is rapidly increasing, and there are few studies specifically looking at pregnant women in this extreme category. The purpose of this article is to highlight some of the challenges faced and review the literature available to help guide obstetricians who might encounter such patients.

Fetal imaging: Executive summary of a Joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and magnetic resonance imaging in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost-effectiveness and to identify research opportunities. This article is the executive summary of the workshop.

Fetal imaging: executive summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging (MRI) in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and MRI in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost effectiveness, and to identify research opportunities. This article is the executive summary of the workshop.

Impact of overweight and obesity on obstetric outcomes

Abnormal nutritional status is an increasingly common complication in developed countries and, as reproductive age women are a part of this trend, the effect of maternal obesity on the pregnancy and neonate must be investigated. Pregestational obesity or overweight condition or an excessive gestational weight gain can be an independent risk factor for feto-maternal complications and long-term risks in adult life for the fetus. The selected risks include infertility, miscarriage, congenital anomalies, hypertensive disorders, gestational diabetes, intrauterine fetal death, macrosomia, and delivery complications. From an etiological point of view, the causes of the adverse outcomes include maternal body habitus, proinflammatory state of obesity, and metabolic dysfunction. Actually, a weight management guidance for obese pregnant women is limited, recommending a gain between 5 and 9 kg during the pregnancy period, while weight loss is discouraged. Mainly, therapeutic approach is prevention using specific programs of reducing weight before pregnant status. In addition, mechanistic studies, in animal models especially, have identified potential areas for intervention which might limit adverse risk factors for obesity from mothers to infants during pregnancy. In this article, a review of the literature on selected obstetrical risks associated with maternal overweight and obesity has been performed and both the target prevention and management strategies have been assessed.

False positive morphologic diagnoses at the anomaly scan: marginal or real problem, a population-based cohort study

BACKGROUND

Congenital malformations occur in 3-4% of live births. Their prenatal detection is performed by ultrasound screening. Any announcement about a suspected malformation is a source of stress for the parents, and misdiagnosis during ultrasound screening can lead to expensive and sometimes iatrogenic medical interventions. In this study, we aim to determine the false-positive rate, first overall and then by anatomical system, of ultrasound screening for congenital malformations in the second and third trimesters of pregnancy.

METHODS

Our sample includes all children born between 1 January, 2006, and 31 December, 2009, in the French region of Auvergne, whose mother had a prenatal ultrasound diagnosis of a congenital malformation during the second or third trimester of pregnancy confirmed by a follow-up ultrasound examination by an expert consultant ultrasonographer. The study included 526 fetuses, divided in 3 groups: false positives, diagnostic misclassifications, and true positives. The rates of false positives and diagnostic misclassifications were calculated for the sample as a whole and then by anatomical system.

RESULTS

Overall, the false-positive rate was 8.8% and the rate of diagnostic misclassification 9.2%. The highest false-positive rates were found for renal and gastrointestinal tract malformations, and the highest diagnostic misclassification rates for cerebral and cardiac malformations. The diagnostic misclassification rate was significantly higher than the false-positive rate for cardiac malformations.

CONCLUSION

The false-positive rate during prenatal ultrasound is not insignificant; these misdiagnoses cause psychological stress for the parents and overmedicalisation of the pregnancy and the child.

Transposition of the great arteries: factors influencing prenatal diagnosis

OBJECTIVE

The objective of this study is to highlight the factors that may affect prenatal diagnosis of transposition of the great arteries (TGA) in order to improve it.

METHODS

This is a retrospective study performed between 2004 and 2009 in the maternity units from North of France. We identified a total of 68 cases of TGA (isolated or associated with only VSD or coarctation of aorta), of which 32 (47.1%) had prenatal diagnosis (PND+) and 36 did not (PND-). Maternal characteristics and ultrasound factors were studied in relation to PND.

RESULTS

Maternal weight and body mass index were significantly higher in the PND- group (70.4 kg and 26.5 kg/m(2) vs 63.6 kg and 23.6 kg/m(2) , respectively). Maternal obesity (body mass index >30) was significantly more frequent in the PND- group (27.8% vs 12.5%). More than a quarter of TGA (28.1%) were diagnosed during the third trimester.

CONCLUSION

Obesity is the main cause of missed PND of TGA. Obese patients with suboptimal prenatal scans may benefit from reassessment of fetal cardiac anatomy and/or from referral for fetal echocardiography.