Impact of maternal body mass index on the antenatal detection of congenital anomalies

Maternal obesity, interpregnancy weight changes and congenital heart defects in the offspring: a nationwide cohort study

OBJECTIVE

To evaluate the association between maternal BMI and congenital heart defects (CHDs) in the offspring when including live births, stillbirths, aborted and terminated pregnancies and to investigate if maternal interpregnancy weight changes between the first and second pregnancy influences the risk of foetal CHDs.

METHODS

A nationwide cohort study of all singleton pregnancies in Denmark from 2008 to 2018. Data were retrieved from the Danish Foetal Medicine Database, which included both pre- and postnatal diagnoses of CHDs. Children or foetuses with chromosomal aberrations were excluded. Odds ratios were calculated with logistic regression models for CHDs overall, severe CHDs and five of the most prevalent subtypes of CHDs.

RESULTS

Of the 547 105 pregnancies included in the cohort, 5 442 had CHDs (1.0%). Risk of CHDs became gradually higher with higher maternal BMI; for BMI 25-29.9 kg/m2, adjusted odds ratio (aOR) 1.17 (95% CI 1.10-1.26), for BMI 30-34.9 kg/m2, aOR 1.21 (95% CI 1.09-1.33), for BMI 35-39.9 kg/m2, aOR 1.29 (95% CI 1.11-1.50) and for BMI ≥ 40 kg/m2, aOR 1.85 (95% CI 1.54-2.21). Data was adjusted for maternal age, smoking status and year of estimated due date. The same pattern was seen for the subgroup of severe CHDs. Among the atrioventricular septal defects (n = 231), an association with maternal BMI ≥ 30 kg/m2 was seen, OR 1.67 (95% CI 1.13-2.44). 109 654 women were identified with their first and second pregnancies in the cohort. Interpregnancy BMI change was associated with the risk of CHDs in the second pregnancy (BMI 2 to < 4 kg/m2: aOR 1.29, 95% CI 1.09-1.53; BMI ≥ 4 kg/m2: aOR 1.36, 95% CI 1.08-1.68).

CONCLUSION

The risk of foetal CHDs became gradually higher with higher maternal BMI and interpregnancy weight increases above 2 BMI units were also associated with a higher risk of CHDs.

Postnatal diagnosis of congenital anomalies despite active systematic prenatal screening policies: a population-based registry study

BACKGROUND

Prenatal screening for congenital anomalies is an important component of maternity care, with continual advances in screening technology. However, few recent studies have investigated the overall effectiveness of a systematic policy of prenatal screening for congenital anomalies, such as in France where an ultrasound per trimester is recommended for all pregnant individuals.

OBJECTIVE

This study aimed to assess the proportion and the type of congenital anomalies that are not detected during pregnancy.

STUDY DESIGN

The study population included all singleton fetuses and newborns with congenital anomalies from the Paris Registry of Congenital Malformations (remaPAR) from 2001 to 2021. The registry includes all live births and stillbirths at ≥22 weeks of gestation and terminations of pregnancy for fetal anomaly at any gestational age with congenital anomalies diagnosed from the prenatal period until discharge home from hospital after birth. The prevalence of postnatally detected congenital anomalies was estimated overall and for 5-year intervals within the study period. We also reported the proportion of postnatal detection by subgroups of congenital anomalies according to the EUROCAT classification.

RESULTS

Of the 16,602 malformed singleton fetuses and newborns, 32.7% were detected postnatally. Of those with severe anomalies, 11.9% were detected postnatally. The postnatal detection rate decreased from 34.3% from 2001 to 2005, to 27.8% from 2016 to 2021 (P<.001). Anomalies most frequently detected postnatally were genital anomalies (n=969; 87.0%), followed by ear, neck, and face anomalies (n=71; 78.0%), eye anomalies (n=154; 74.0%), and limb anomalies (n=1802; 68.4%). Anomalies of the kidneys and the urinary tract (n=219; 7.1%) and the abdominal wall (n=37; 8.7%) were least likely to be detected after birth. Among the anomalies classified as severe, postnatal detection rates were highest for limb reduction defects (n=142; 40.6%), complete transposition of the great arteries (n=31; 17.6%), and diaphragmatic hernia (n=26; 17.2%).

CONCLUSION

Despite improvement of prenatal screening over a 20-year period, our results show that there is still a margin for improvement in prenatal diagnosis of congenital anomalies.

Interpregnancy Body Mass Index Change and Offspring Mortality Risk following the Second Pregnancy

OBJECTIVE

The aim of the study is to examine the impact of maternal interpregnancy body mass index (BMI) change on subsequent offspring mortality risk.

STUDY DESIGN

This is a retrospective cohort study of women who had two consecutive live singleton deliveries of at least 20 weeks' gestation from the Utah Population Database. Our exposure was defined as interpregnancy BMI change from the date of first delivery to the conception date of subsequent pregnancy. We categorized BMI change as: < - 1, -1 to 0, 0 to <1 (reference), 1 to 2, 2 to 4, ≥4 kg/m2. Our primary outcome was all-cause age-specific mortality during four time periods: neonatal (≤28 days), infant (29 days to <1 year old), childhood ((≥1 to <5 years old), and late childhood (5 to <18 years old). We also examined mortality specifically attributed to congenital anomalies. Analyses used Cox proportional hazard models stratified by full term (≥37 weeks) and preterm (<37 weeks) deliveries. All models were adjusted for relevant confounders.

RESULTS

Of 266,752 women, among full-term deliveries, women with a BMI increase of 4 kg/m2 or more had an increased risk of neonatal mortality in their subsequent pregnancy (hazard ratio or HR = 1.72, 95% confidence interval or CI: 1.23-2.41) Women who lost 1 kg/m2 or more between deliveries also had increased neonatal mortality (HR = 1.46, 95% CI: 1.04-2.05). There were no differences in infant, early, or late childhood mortality by interpregnancy BMI change. Maternal interpregnancy interval weight loss of 1 kg/m2 or more and weight gain of ≥4 kg/m2 also had increased risk of mortality associated with congenital anomalies or conditions arising during the neonatal period following their subsequent delivery.

CONCLUSION

Women with significant interpregnancy weight gain and modest weight loss have a significant increased risk of neonatal mortality following their subsequent pregnancy.

KEY POINTS

· Significant weight gain between deliveries increases the risk of neonatal death.. · Modest weight loss between deliveries increases the risk of neonatal death.. · This risk may be partially explained by increased risk of congenital malformations..

Obesity in Pregnancy: A Comprehensive Review of Influential Guidelines

Importance

Obesity is one of the most common clinical entities complicating pregnancies and is associated with short- and long-term consequences for both the mother and the offspring.

Objective

The aim of this study were to review and compare the most recently published influential guidelines on the management of maternal obesity in the preconceptional, antenatal, intrapartum, and postpartum period.

Evidence Acquisition

A descriptive review of guidelines from the American College of Obstetricians and Gynecologists, the International Federation of Gynecology and Obstetrics, the Society of Obstetricians and Gynecologists of Canada, the Royal College of Obstetricians and Gynecologists, and the Royal Australian and New Zealand College of Obstetricians and Gynecologists on obesity in pregnancy was carried out.

Results

There is an overall agreement among the reviewed guidelines regarding the importance of prepregnancy weight loss with behavioral modification, optimization of gestational weight gain, and screening for comorbidities in improving pregnancy outcomes of obese women. Women with previous bariatric surgery should be screened for nutritional deficiencies and have a closer antenatal surveillance, according to all guidelines. In addition, folic acid supplementation is recommended for 1 to 3 months before conception and during the first trimester, but several discrepancies were identified with regard to other vitamins, iodine, calcium, and iron supplementation. All medical societies recommend early screening for gestational diabetes mellitus and early anesthetic assessment in obese women and suggest the use of aspirin for the prevention of preeclampsia when additional risk factors are present, although the optimal dosage is controversial. The International Federation of Gynecology and Obstetrics, Society of Obstetricians and Gynecologists of Canada, Royal College of Obstetricians and Gynecologists, and Royal Australian and New Zealand College of Obstetricians and Gynecologists point out that specific equipment and adequate resources must be readily available in all health care facilities managing obese pregnant women. Moreover, thromboprophylaxis and prophylactic antibiotics are indicated in case of cesarean delivery, and intrapartum fetal monitoring is justified during active labor in obese patients. However, there are no consistent protocols regarding the fetal surveillance, the monitoring of multiple gestations, the timing and mode of delivery, and the postpartum follow-up, although weight loss and breastfeeding are unanimously supported.

Conclusions

Obesity in pregnancy is a significant contributor to maternal and perinatal morbidity with a constantly rising global prevalence among reproductive-aged women. Thus, the development of uniform international protocols for the effective management of obese women is of paramount importance to safely guide clinical practice and subsequently improve pregnancy outcomes.

Morbidly obese pregnant woman with congenital leptin deficiency: Follow-up and obstetric outcome

Congenital leptin deficiency is a rare congenital genetic disease. It is characterized by early-onset, severe morbid obesity. The disease occurs due to mutations in the LEP gene. Obesity is a severe consequence of the disease. It also causes reproductive and obstetric complications. In this study, we present a 26-year-old pregnant case who had been previously diagnosed with congenital leptin deficiency. The pregnancy made it more difficult to regulate the metabolic changes caused by the disease. Problems were held by a multidisciplinary approach, with the contribution of endocrinology and cardiology departments. The patient gave birth to a healthy girl at the 37th week of gestation. Spontaneous pregnancy resulting in a live birth is very uncommon in women with congenital leptin deficiency. The follow-up and treatment approaches during pregnancy and the obstetric outcome are presented with the literature.

Accuracy and Completion Rate of the Fetal Anatomic Survey in the Super Obese Parturient

OBJECTIVE

To determine the completion rate of ultrasound in with a body mass index (BMI) ≥ 50 to women with BMI 18.5 to 29.9.

STUDY DESIGN

This study was a retrospective cohort study. Women with a singleton pregnancy, age 18 to 45 with a BMI ≥50 that delivered between 2013-2016 were compared to women with a BMI 18.5 to 29.9 during that same time period to assess the accuracy and, as a second aim, the completion rate of the fetal anatomic survey. Data were analyzed using two-sample t test, chi-square test, or logistic regression as appropriate.

RESULTS

Eighty-one cases with a BMI ≥50 were compared with 81 patients with a BMI 18.5 to 29.9. Maternal demographics and timing (gestational age) at the time of the ultrasound were similar between groups. In women with a BMI 18.5 to 29.9, completion of anatomy was 58% of the time with the first ultrasound, 81% with second ultrasound, and 84% with the third ultrasound. In women with BMI ≥50, completion of anatomy was 10% of the time with the first ultrasound, 33% with the second ultrasound, and 42% with the third ultrasound. Each time frame was statistically significant. Agreement level on the accuracy to detect fetal anomalies between groups were not statistically significant between the groups.

CONCLUSION

In women with a BMI ≥50 compared to women with BMI of 18.8 to 29.9, more ultrasounds are needed to complete the anatomic survey although overall accuracy in fetal anomaly detection is similar.

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.

Maternal obesity and metabolic disorders associate with congenital heart defects in the offspring: A systematic review

BACKGROUND

Congenital heart defects (CHDs) are the most common congenital malformations. The aetiology of CHDs is complex. Large cohort studies and systematic reviews and meta-analyses based on these have reported an association between higher risk of CHDs in the offspring and individual maternal metabolic disorders such as obesity, diabetes, hypertension, and preeclampsia, all conditions that can be related to insulin resistance or hyperglycaemia. However, the clinical reality is that these conditions often occur simultaneously. The aim of this review is, in consequence, both to evaluate the existing evidence on the association between maternal metabolic disorders, defined as obesity, diabetes, hypertension, preeclampsia, dyslipidaemia and CHDs in the offspring, as well as the significance of combinations, such as metabolic syndrome, as risk factors.

METHODS

A systematic literature search of papers published between January 1, 1990 and January 14, 2021 was conducted using PubMed and Embase. Studies were eligible if they were published in English and were case-control or cohort studies. The exposures of interest were maternal overweight or obesity, hypertension, preeclampsia, diabetes, dyslipidaemia, and/or metabolic syndrome, and the outcome of interest was CHDs in the offspring. Furthermore, the studies were included according to a quality assessment score.

RESULTS

Of the 2,250 identified studies, 32 qualified for inclusion. All but one study investigated only the individual metabolic disorders. Some disorders (obesity, gestational diabetes, and hypertension) increased risk of CHDs marginally whereas pre-gestational diabetes and early-onset preeclampsia were strongly associated with CHDs, without consistent differences between CHD subtypes. A single study suggested a possible additive effect of maternal obesity and gestational diabetes.

CONCLUSIONS

Future studies of the role of aberrations of the glucose-insulin homeostasis in the common aetiology and mechanisms of metabolic disorders, present during pregnancy, and their association, both as single conditions and-particularly-in combination, with CHDs are needed.

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.

Adverse effects of pre-pregnancy maternal underweight on pregnancy and perinatal outcomes in a freeze-all policy

BACKGROUND

Underweight and overweight may affect reproduction and interfere with treatment of infertility. In the present retrospective analysis, we sought to evaluate the effect of low body mass index (BMI) on pregnancy and perinatal outcomes in frozen-thawed embryo transfer (FET) cycles.

METHODS

This study involved 8755 FET cycles in a single IVF center during the period from January 2009 to December 2018. Both pregnancy and perinatal outcomes were assessed in women who were underweight, normal weight, and overweight as defined based on a respective BMI < 18.5 kg/m², ≥ 18.5 BMI < 24.9 kg/m², and BMI ≥ 25 kg/m².

RESULTS

Being underweight was linked to reduced implantation rates as compared to a normal weight (33.56% vs. 37.26%). Similarly, when comparing outcomes in underweight women to those in normal weight women, rates of clinical pregnancy (48.14% vs. 53.85%) and ongoing pregnancy (43.04% vs. 50.47%) were reduced. Rates of miscarriage were markedly reduced in the normal weight group relative to the overweight group (10.73% vs. 13.37%). Perinatal outcomes were largely comparable for all groups, with the exception of very low birth weight rates (normal weight:0.58% vs. overweight: 2.03%), very small for gestational age rates (normal weight:1.31% vs. overweight:3.55%) and very preterm delivery rates (normal weight:0.82% vs. overweight: 2.03%), which were significantly elevated for overweight mothers.

CONCLUSIONS

These results indicate that being underweight is linked to negative pregnancy outcomes when undergoing FET-based IVF.

Quantification of selection bias in studies of risk factors for birth defects among livebirths

BACKGROUND

Risk factors for birth defects are frequently investigated using data limited to liveborn infants. By conditioning on survival, results of such studies may be distorted by selection bias, also described as "livebirth bias." However, the implications of livebirth bias on risk estimation remain poorly understood.

OBJECTIVES

We sought to quantify livebirth bias and to investigate the conditions under which it arose.

METHODS

We used data on 3994 birth defects cases and 11 829 controls enrolled in the National Birth Defects Prevention Study to compare odds ratio (OR) estimates of the relationship between three established risk factors (antiepileptic drug use, smoking, and multifetal pregnancy) and four birth defects (anencephaly, spina bifida, omphalocele, and cleft palate) when restricted to livebirths as compared to among livebirths, stillbirths, and elective terminations. Exposures and birth defects represented varying strengths of association with livebirth; all controls were liveborn. We performed a quantitative bias analysis to evaluate the sensitivity of our results to excluding terminated and stillborn controls.

RESULTS

Cases ranged from 33% liveborn (anencephaly) to 99% (cleft palate). Smoking and multifetal pregnancy were associated with livebirth among anencephaly (crude OR [cOR] 0.61 and cOR 3.15, respectively) and omphalocele cases (cOR 2.22 and cOR 5.22, respectively). For analyses of the association between exposures and birth defects, restricting to livebirths produced negligible differences in estimates except for anencephaly and multifetal pregnancy, which was twofold higher among livebirths (adjusted OR [aOR] 4.93) as among all pregnancy outcomes (aOR 2.44). Within tested scenarios, bias analyses suggested that results were not sensitive to the restriction to liveborn controls.

CONCLUSIONS

Selection bias was generally limited except for high mortality defects in the context of exposures strongly associated with livebirth. Findings indicate that substantial livebirth bias is unlikely to affect studies of risk factors for most birth defects.

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.

Association between prepregnancy body mass index and risk of congenital heart defects in offspring: an ambispective observational study in China

BACKGROUND

Congenital heart defects (CHDs) are the most common birth defect around the world. Maternal prepregnancy obesity has been proposed as a risk factor of CHDs, but the relationship of CHD risk with over- and underweight is controversial, especially because body mass index (BMI) distribution differs between Asia and the West. The study aimed to examine the potential associations of maternal over- and underweight on risk of offspring CHDs.

METHODS

An ambispective observational study involving 1206 fetuses with CHDs and 1112 fetuses without defects at seven hospitals in China was conducted. Standardized questionnaires were used to collect information on maternal prepregnancy weight and height, social demographic characteristics, living and occupational environments, and lifestyle behaviors. Univariate, multivariate and multilevel logistic regression as well as unrestricted cubic spline analysis were used to examine potential associations of prepregnancy BMI and offspring CHDs.

RESULTS

Prepregnancy maternal underweight (BMI<18.5) or low average BMI (18.5 ≤ BMI<21.25) was associated with significantly higher risk of CHD in offspring than high average BMI (21.25 ≤ BMI<24.0): multilevel logistic regression indicated adjusted odds ratios of 1.53 (95%CI 1.13, 2.08) for underweight, 1.44 (95%CI 1.10, 1.89) for low average BMI and 1.29 (95%CI 0.84, 1.97) for overweight or obesity (BMI ≥ 24.0). Mothers with prepregnancy BMI < 21.25 were at greater risk of offspring with septal defects, while mothers with low average BMI were at greater risk of offspring with conotruncal defects and septal defects.

CONCLUSIONS

Our findings suggest that underweight or low average BMI may be associated with higher risk of CHDs in offspring. Health professionals may wish to advise women planning to be pregnant to maintain or even gain weight to ensure adequate, balanced nutrition and thereby reduce the risk of CHDs in their offspring.

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.

Second trimester ultrasound detection of fetal anomalies in the obese obstetrical population: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this review is to identify, appraise and synthesize the best available evidence on the impact of maternal obesity on mid second trimester ultrasound detection of fetal anomalies in pregnancy.

Maternal body mass index and access to antenatal care: a retrospective analysis of 619,502 births in England

BACKGROUND

Late access to antenatal care increases risks of adverse outcomes including maternal and perinatal mortality. There is evidence that BMI influences patient engagement with health services, such as cancer screening services and delayed access to treatment; this association has not been fully explored in the context of antenatal care. This study investigated the association between the stage of pregnancy women access antenatal care, BMI, and other socio-demographic factors.

METHODS

Retrospective analysis of routine hospital data from 34 NHS maternity units in England, UK, including 619,502 singleton births between 1989 and 2007. Analyses used logistic regression to investigate the association between maternal BMI categories and stage of pregnancy women accessed antenatal care. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were used to estimate associations, adjusting for maternal age, ethnic group, parity, Index of Multiple Deprivation score and employment status. The primary outcome was late access to antenatal care (>13+6 weeks). Secondary outcomes were trimester of access, and the association between late access and other socio-demographic variables.

RESULTS

Women with an overweight or obese BMI accessed antenatal care later than women with a recommended BMI (aOR 1.11, 95%CI 1.09-1.12; aOR 1.04, 95%CI 1.02-1.06 respectively), and underweight women accessed care earlier (aOR 0.77, 95%CI 0.74-0.81). Women with obesity were 42% more likely to access care in the third trimester compared with women with a recommended BMI. Additional significant socio-demographic associations with late access included women from minority ethnic groups, teenagers, unemployment and deprivation. The greatest association was observed among Black/Black British women accessing care in the third trimester (aOR 5.07, 95% CI 4.76, 5.40).

CONCLUSIONS

There are significant and complex socio-demographic inequalities associated with the stage of pregnancy women access maternity care, particularly for women with obesity accessing care very late in their pregnancy, and among BME groups, teenagers, deprived and unemployed women. These populations are at increased risk of adverse maternal and fetal outcomes and require support to address inequalities in access to antenatal care. Interventions to facilitate earlier access to care should address the complex and inter-related nature of these inequalities to improve pregnancy outcomes among high-risk groups.

Clinical management of pregnancy in the obese mother: before conception, during pregnancy, and post partum

The global epidemic of obesity has led to an increasing number of obese women of reproductive age. Obesity is associated with reduced fertility, and pregnancies complicated by maternal obesity are associated with adverse outcomes, including increased risk of gestational diabetes, pre-eclampsia, preterm birth, instrumental and caesarean births, infections, and post-partum haemorrhage. The medical and obstetric management of obese women is focused on identifying, addressing, and preventing some of these associated complications, and is a daunting challenge given the high percentage of patients with obesity and few therapeutic options proven to improve outcomes in this population. The UK's National Institute for Health and Care Excellence guidelines and the American College of Obstetricians and Gynecologists recommend that all pregnant women follow a healthy diet, and consider at least half an hour of moderate physical activity per day during pregnancy. However, although obese women are often directed to seek the advice of a nutritionist and to limit gestational weight gain, guidelines for the management of pregnancy and delivery in this high-risk group are lacking. The post-partum period represents an important opportunity to optimise maternal health before the next pregnancy. As many of the physiological changes of pregnancy associated with maternal obesity are present from early pregnancy onward, reducing maternal obesity before conception is probably the best strategy to decrease the health burden associated with maternal obesity.

Preconceptional and maternal obesity: epidemiology and health consequences

Obesity in women of reproductive age is increasing in prevelance worldwide. Obesity reduces fertility and increases time taken to conceive, and obesity-related comorbidities (such as type 2 diabetes and chronic hypertension) heighten the risk of adverse outcomes for mother and child if the woman becomes pregnant. Pregnant women who are obese are more likely to have early pregnancy loss, and have increased risk of congenital fetal malformations, delivery of large for gestational age infants, shoulder dystocia, spontaneous and medically indicated premature birth, and stillbirth. Late pregnancy complications include gestational diabetes and pre-eclampsia, both of which are associated with long-term morbidities post partum. Women with obesity can also experience difficulties during labour and delivery, and are more at risk of post-partum haemorrhage. Long-term health risks are associated with weight retention after delivery, and inherent complications for the next pregnancy. The wellbeing of the next generation is also compromised. All these health issues could be avoided by prevention of obesity among women of reproductive age, which should be viewed as a global public health priority. For women who are already obese, renewed efforts should be made towards improved management during pregnancy, especially of blood glucose, and increased attention to post-partum weight management. Effective interventions, tailored to ethnicity and culture, are needed at each of these stages to improve the health of women and their children in the context of the global obesity epidemic.

Completion and Sensitivity of the Second-Trimester Fetal Anatomic Survey in Obese Gravidas

OBJECTIVES

To estimate the effect of maternal body mass index (BMI) on the completion of fetal anatomic surveys before 20 weeks' estimated gestational age (GA).

METHODS

We conducted a retrospective cohort study of singletons undergoing standard or detailed anatomic sonographic examinations from 2006 to 2014. Patients were categorized by ranges of BMI. The primary outcomes were completion of standard and detailed anatomic surveys before 20 weeks' estimated GA. The effect of the BMI category was assessed by the χ² test for trends and analysis of variance.

RESULTS

Of 15,313 patients, 5917 (38%) were obese, and 1581 (10%) had a BMI of 40 kg/m² or higher. Standard (P < .01) and detailed (P < .01) surveys were less likely to be completed as the BMI category increased. Suboptimal visualization of the fetal chest (P < .01), abdomen (P < .01), and extremities (P < .01) significantly contributed to the decreased standard survey completion rates. Suboptimal visualization of the fetal head (P < .01) and chest (P < .01) significantly contributed to the decreased detailed survey completion rates. There was no statistically significant difference in the sensitivity of a completed standard or detailed anatomic survey for the detection of fetal anomalies.

CONCLUSIONS

An increasing BMI category was associated with decreased completion of standard and detailed anatomic surveys by 20 weeks' estimated GA. Strategies to improve early visualization of the fetal head, chest, and abdomen in obese women should be investigated to promote anomaly detection and appropriate counseling.

Low Gestational Weight Gain and Risk of Adverse Perinatal Outcomes in Obese and Severely Obese Women

BACKGROUND

Our objective was to estimate associations between gestational weight gain z scores and preterm birth, neonatal intensive care unit admission, large- and small-for-gestational age birth, and cesarean delivery among grades 1, 2, and 3 obese women.

METHODS

We included singleton infants born in Pennsylvania (2003-2011) to grade 1 (body mass index 30-34.9 kg/m, n = 148,335), grade 2 (35-39.9 kg/m, n = 72,032), or grade 3 (≥40 kg/m, n = 47,494) obese mothers. Total pregnancy weight gain (kg) was converted to gestational age-standardized z scores. Multivariable Poisson regression models stratified by obesity grade were used to estimate associations between z scores and outcomes. A probabilistic bias analysis, informed by an internal validation study, evaluated the impact of body mass index and weight gain misclassification.

RESULTS

Risks of adverse outcomes did not substantially vary within the range of z scores equivalent to 40-week weight gains of -4.3 to 9 kg for grade 1 obese, -8.2 to 5.6 kg for grade 2 obese, and -12 to -2.3 kg for grade 3 obese women. As gestational weight gain increased beyond these z score ranges, there were slight declines in risk of small-for-gestational age birth but rapid rises in cesarean delivery and large-for-gestational age birth. Risks of preterm birth and neonatal intensive care unit admission were weakly associated with weight gain. The bias analysis supported the validity of the conventional analysis.

CONCLUSIONS

Gestational weight gain below national recommendations for obese mothers (5-9 kg) may not be adversely associated with fetal growth, gestational age at delivery, or mode of delivery.

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.

Low Gestational Weight Gain in Obese Women and Pregnancy Outcomes

Obesity during pregnancy and excessive weight gain during this period are associated with several maternal-fetal and neonatal complications. Moreover, a significant percentage of women have weight retention in the postpartum period, especially those with excessive weight gain during pregnancy. The recommendations of the 2009 Institute of Medicine were based on observational studies that have consistently shown that women with weight gain within the recommended range had better outcomes during pregnancy. In patients with obesity, however, there is no recommendation for weight gain, according to the class of obesity. This review, therefore, aims to evaluate the evidence on key maternal and fetal complications related to low weight gain during pregnancy in obese and overweight patients.

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.

Maternal prepregnancy obesity and cause-specific stillbirth

BACKGROUND

In high-income countries, maternal obesity is one of the most important modifiable causes of stillbirth, yet the pathways underpinning this association remain unclear.

OBJECTIVE

We estimated the association between maternal prepregnancy body mass index (BMI) and the risk of stillbirth defined by pathophysiologic contributors or causes.

DESIGN

Using a case-cohort design, we randomly sampled 1829 singleton deliveries from a cohort of 68,437 eligible deliveries at Magee-Womens Hospital in Pittsburgh, Pennsylvania (2003-2010), and augmented it with all remaining cases of stillbirth for a total of 658 cases. Stillbirths were classified based on probable cause(s) of death (maternal medical conditions, obstetric complications, fetal abnormalities, placental diseases, and infection). A panel of clinical experts reviewed medical records, placental tissue slides and pathology reports, and fetal postmortem reports of all stillbirths. Causes of fetal death were assigned by using the Stillbirth Collaborative Research Network Initial Causes of Fetal Death protocol from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Proportional hazards models were used to estimate the BMI-stillbirth association after adjustment for confounders.

RESULTS

The rate of stillbirth among lean, overweight, obese, and severely obese women was 7.7, 10.6, 13.9, and 17.3 per 1000 live-born and stillborn infants, respectively. Adjusted stillbirth HRs (95% CIs) were 1.4 (1.1, 1.8) for overweight, 1.8 (1.3, 2.4) for obese, and 2.0 (1.5, 2.8) for severely obese women, respectively, compared with lean women; associations strengthened when limited to antepartum stillbirths. Obesity and severe obesity were associated with stillbirth resulting from placental diseases, hypertension, fetal anomalies, and umbilical cord abnormalities. BMI was not related to stillbirth caused by placental abruption, obstetric conditions, or infection.

CONCLUSIONS

Multiple mechanisms appear to link obesity to stillbirth. Interventions to reduce stillbirth among obese mothers should consider targeting stillbirth due to hypertension and placental diseases-the most common causes of fetal death in this at-risk group.

Accuracy of sonographic chorionicity classification in twin gestations

OBJECTIVES

To evaluate the accuracy of sonographic classification of chorionicity in a large cohort of twins and investigate which factors may be associated with sonographic accuracy.

METHODS

We conducted a secondary analysis of a randomized trial of preterm birth prevention in twins. Sonographic classification of chorionicity was compared with pathologic examination of the placenta. Maternal (age, body mass index, diabetes, and hypertension), obstetric (prior cesarean delivery, gestational age at the first sonographic examination, and antepartum bleeding), and sonographic (oligohydramnios, polyhydramnios, and twin-twin transfusion syndrome) factors were assessed for their possible association with accuracy.

RESULTS

A total of 545 twin sets in which chorionicity was classified by sonography before 20 weeks' gestation were included; 455 were dichorionic and 90 were monochorionic based on pathologic examination. Sonography misclassified 35 of 545 twin pregnancies (6.4%): 18 of 455 dichorionic twins (4.0%) and 17 of 90 monochorionic twins (19.0%). The sensitivity and specificity of sonographic diagnosis of monochorionicity were 81.1% and 96.0%, respectively. In a multivariable analysis, pregnancies with initial sonographic examinations before 14 weeks' gestation were less likely to have misclassified chorionicity than those with sonographic examinations at 15 to 20 weeks (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.23-0.96). For each week increase in gestational age, the odds of misclassification rose by 10% (OR, 1.10; 95% CI, 1.01-1.2). In the multivariable analysis, maternal age, body mass index, parity, and prior cesarean delivery were not associated with sonographic accuracy.

CONCLUSIONS

Sonography before 20 weeks incorrectly classified chorionicity in 6.4% of twin gestations. Those with first sonographic examinations performed at earlier gestational ages had improved chorionicity diagnosis.

Placental dysfunction in obese women and antenatal surveillance strategies

This review is aimed at discussing placental dysfunction in obesity and its clinical implication in pregnancy as well as an antenatal surveillance strategy for these women. Maternal obesity is associated with adverse perinatal outcome. Obesity is an independent risk factor for fetal hyperinsulinaemia, birthweight and newborn adiposity. Maternal obesity is associated with childhood obesity and obesity in adult life. Obesity induces a low-grade inflammatory response in placenta, which results in short- and long-term programming of obesity in fetal life. Preconception and antenatal counselling on obstetrics risk in pregnancy, on diet and lifestyle in pregnancy and on gestational weight gain is associated with a better outcome. Fetal growth velocity is closely associated with maternal weight and gestational weight gain. Careful monitoring of gestational weight gain and fetal growth, and screening and management of obstetrical complications such as gestational diabetes and pre-eclampsia, improves perinatal outcome. The use of metformin in non-diabetic obese women is under investigation; further evidence is required before recommending it.

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.

Prepregnancy obesity and the risk of birth defects: an update

The growing number of obese women worldwide has many implications for the reproductive health outcomes of mothers and their children. Specifically, prepregnancy obesity has been associated with certain major birth defects. Provided here is a summary of the most recent and comprehensive meta-analysis of reports of associations between prepregnancy obesity and birth defects, along with an update that includes a brief overview of reports of similar associations published since that meta-analysis. The possible reasons for the observed association between prepregnancy obesity and birth defects are explored, and knowledge gaps that suggest possible avenues for future research are highlighted.

Improved antenatal detection of congenital anomalies in women with pre-gestational diabetes: population-based cohort study

AIMS

To compare antenatal detection of congenital anomaly in women with and without pre-gestational diabetes and their pregnancy outcomes in a regional cohort study.

METHODS

Data from a total of 7148 singleton pregnancies with a congenital anomaly delivered between 1 January 1996 and 31 December 2008 were extracted from the Northern Diabetes in Pregnancy and Northern Congenital Abnormality Surveys. Antenatal ultrasound detection rates of congenital anomaly in pregnancies complicated by major non-chromosomal congenital anomaly and resulting in live birth, stillbirth, late miscarriage (20-23 weeks of gestation) or termination of pregnancy for a congenital anomaly, were compared between women with and without diabetes (120 and 7028, respectively).

RESULTS

A significantly higher rate of antenatal detection of congenital anomalies was observed in women with diabetes compared with women without diabetes (50.8 vs. 38.6%, respectively; relative risk 1.32; 95% CI 1.10-1.57; P = 0.003). Cardiovascular anomalies were the only group with a significantly higher antenatal detection rate in women with diabetes (31.8 vs. 10.4%; relative risk 3.05; 95% CI 1.95-4.76; P < 0.00001). This difference remained after excluding cases of ventricular septal defect (52.2 vs. 16.3%; relative risk 3.20; 95% CI 2.13-4.80; P < 0.0001). Among women with diabetes, male fetal sex was the only factor associated with a higher antenatal detection rate. There were no differences in the rates of termination of pregnancy, late miscarriage, stillbirth or infant death between groups.

CONCLUSIONS

Antenatal detection of cardiovascular anomalies was higher in women with diabetes, suggesting that recommendations for enhanced cardiovascular scanning may improve detection. Greater awareness of the increased risk of anomalies in other organ systems is needed.

Maternal reporting of prenatal ultrasounds among women in the National Birth Defects Prevention Study

BACKGROUND

Increased availability and usage of ultrasound screening have led to improved identification of fetal structural abnormalities prenatally. Few population-based studies have been published on prenatal detection for structural birth defects in the United States. The aim of this study is to determine the frequency of maternal reporting of abnormal prenatal ultrasounds for selected birth defects and to investigate associated maternal characteristics.

METHODS

Participants included 4013 mothers enrolled in the National Birth Defects Prevention Study who carried a fetus with at least one of 14 structural birth defects between 1997 and 2004. Frequencies of abnormal prenatal ultrasounds were based on maternal report and computed for isolated and multiple defects. Associations between maternal characteristics and abnormal prenatal ultrasounds were assessed using logistic regression.

RESULTS

Overall, 46% of participants reported an abnormal ultrasound. Infants with omphalocele, anencephaly, gastroschisis, and renal agenesis were more likely to have abnormal prenatal ultrasounds than those with cleft and limb abnormalities. Hispanic women were less likely to report abnormal prenatal ultrasounds of birth defects than Caucasians, as were women who had a body mass index ≥ 30 kg/m(2) compared with those with a normal body mass index.

CONCLUSION

Of the 14 selected birth defects in this study, less than half were reported by mothers of affected infants to have had an abnormal ultrasound during pregnancy. The frequency of reporting abnormal prenatal ultrasounds varies by type of defect, maternal race/ethnicity, and maternal body mass index status.

Errors in prenatal diagnosis

Prenatal screening and diagnosis are integral to antenatal care worldwide. Prospective parents are offered screening for common fetal chromosomal and structural congenital malformations. In most developed countries, prenatal screening is routinely offered in a package that includes ultrasound scan of the fetus and the assay in maternal blood of biochemical markers of aneuploidy. Mistakes can arise at any point of the care pathway for fetal screening and diagnosis, and may involve individual or corporate systemic or latent errors. Special clinical circumstances, such as maternal size, fetal position, and multiple pregnancy, contribute to the complexities of prenatal diagnosis and to the chance of error. Clinical interventions may lead to adverse outcomes not caused by operator error. In this review I discuss the scope of the errors in prenatal diagnosis, and highlight strategies for their prevention and diagnosis, as well as identify areas for further research and study to enhance patient safety.