Major, non-chromosomal, birth defects and maternal physical activity: a systematic review

Maternal physical activity, sitting, and risk of non-cardiac birth defects

BACKGROUND

The relationship between maternal physical activity (PA)/sitting and birth defects is largely unexplored. We examined whether pre-pregnancy PA/sitting were associated with having a pregnancy affected by a birth defect.

METHODS

We used data from two United States population-based case-control studies: 2008-2011 deliveries from the National Birth Defects Prevention Study (NBDPS; 9 states) and 2014-2018 deliveries from the Birth Defects Study To Evaluate Pregnancy exposureS (BD-STEPS; 7 states). Cases with one of 12 non-cardiac birth defects (n = 3798) were identified through population-based registries. Controls (n = 2682) were live-born infants without major birth defects randomly sampled using vital/hospital records. Mothers self-reported pre-pregnancy PA/sitting. Unconditional logistic regression models estimated associations between PA/sitting categories and the 12 birth defects.

RESULTS

Mothers engaging in pre-pregnancy PA was associated with a reduced odds of five (spina bifida, cleft palate, anorectal atresia, hypospadias, transverse limb deficiency) and a higher odds of two (anencephaly, gastroschisis) birth defects. Mothers spending less time sitting in pre-pregnancy was associated with a reduced odds of two (anorectal atresia, hypospadias) and a higher odds of one (cleft lip with or without cleft palate) birth defect.

CONCLUSIONS

Reasonable next steps include replication of these findings, improved exposure assessment, and elucidation of biologic mechanisms.

IMPACT

Using data from two population-based case-control studies, we found that mothers engaging in different types of physical activity in the 3 months before pregnancy had an infant with a reduced odds of five and a higher odds of two birth defects. Mothers spending less time sitting in the 3 months before pregnancy had an infant with a reduced odds of two and a higher odds of one birth defect. Clarification and confirmation from additional studies are needed using more precise exposure measures, distinguishing occupational from leisure-time physical activity, and elucidation of mechanisms supporting these associations.

Relationships between Women's and Men's Modifiable Preconception Risks and Health Behaviors and Maternal and Offspring Health Outcomes: An Umbrella Review

Parental health before conception effects maternal and offspring health outcomes. Preconception care provides healthcare to prospective parents addressing modifiable preconception risks and health behaviors. This umbrella review aimed to consolidate evidence on women's and men's modifiable preconception risks or health behaviors associated with maternal and offspring health outcomes. MEDLINE, EMBASE, Maternity and Infant Care, CINAHL, and PsycINFO were searched from March 4, 2010, to March 4, 2020. Eligible studies were systematic reviews or meta-analyses of observational studies examining associations between modifiable preconception risks or health behaviors and maternal and offspring health outcomes. Screening, data extraction, and methodological quality assessment (AMSTAR 2) occurred independently by two reviewers. Degree of overlap was examined. Findings were summarized for evidence synthesis. Twenty-seven systematic reviews were included. Modifiable preconception risks and health behaviors were identified across categories: body composition (e.g., overweight, obesity), lifestyle behaviors (e.g., caffeine, smoking), nutrition (e.g., micronutrients), environmental exposures (e.g., radiation), and birth spacing (e.g., short interpregnancy intervals). Outcomes associated with exposures affected embryo (e.g., embryonic growth), maternal (e.g., gestational diabetes mellitus), fetal/neonate (e.g., preterm birth), and child (e.g., neurocognitive disorders) health. For real-world practice and policy relevance, evidence-based indicators for preconception care should include body composition, lifestyle, nutrition, environmental, and birth spacing.

Maternal occupational physical activity and risk for orofacial clefts

OBJECTIVES

To perform a case-control study of maternal occupational physical activity and risk for orofacial clefts in Texas during 1999-2009.

METHODS

We used logistic regression to assess 14 measures of physical activity estimated from a job exposure matrix, using the maternal occupation reported on the birth certificate, among 887 children with cleft lip with or without cleft palate (CLP), 436 children with cleft palate only (CP), and 1932 controls.

RESULTS

After adjusting for several potential confounders, seven measures of physical activity (as a categorical and/or continuous variable) were significantly associated with CLP, CP, or both. Positive associations were seen for keeping balance, kneeling, standing, and walking/running (odds ratio 95% confidence interval range 1.0-1.9 for fourth versus first quartile). A significant positive trend was also seen for bending/twisting. Negative associations were seen for repetitive motion and sitting.

CONCLUSIONS

Maternal occupational physical activity may be related to the etiology of orofacial clefts.

Adaptation of Maternal-Fetal Physiology to Exercise in Pregnancy: The Basis of Guidelines for Physical Activity in Pregnancy

Only 50 years ago obstetric care providers and women had many concerns regarding whether exercise during pregnancy created a harmful competition for substrate resources between the fetus and the mother. Animal and human research in the past 50 years, which includes acute and chronic aerobic exercise during pregnancy, has a reassuring margin of safety throughout gestation in women. Maternal physiology adapts to pregnancy changes involving the cardiorespiratory and glucometabolic alterations. Due to these changes, pregnant women have slight differences in response to acute exercise sessions. Chronic exposure to aerobic exercise before and during pregnancy is associated with numerous maternal and neonatal adaptations which may have short- and long-term benefits to maternal and child health. On the basis of the consistent evidence of safety of exercise during pregnancy, multiple nations and health care organizations, including the American College of Obstetrics and Gynecology, recommend moderate exercise for 20 to 30 minutes most days of the week. Despite the 15 to 20 years since the first recommendations were made, only 10% to 15% of pregnant women meet this recommendation. It seems there may be 2 foci for failure to achieve these exercise recommendations: patient specific and culturally driven and/or obstetric provider not recommending regular exercise due to lack of knowledge or motivation. This article addresses the provider knowledge by a review of the normal (at rest) physiologic adaptation to pregnancy. Then, we provide a detailed description of the type and intensity of controlled experiments that document the safety of exercise during pregnancy. The short- and long-term benefits are reviewed, including the safety in moderate-risk women.

Next steps for birth defects research and prevention: The birth defects study to evaluate pregnancy exposures (BD-STEPS)

BACKGROUND

The Birth Defects Study To Evaluate Pregnancy exposureS (BD-STEPS) is a population-based, multi-Center case-control study of modifiable risk factors for selected birth defects in the United States. BD-STEPS is the second major research effort of the Centers for Birth Defects Research and Prevention, which extends and expands the initial research effort, the National Birth Defects Prevention Study (NBDPS).

METHODS

BD-STEPS focuses on 17 categories of structural birth defects selected based on severity, prevalence, consistent ascertainment, and previous findings that warrant additional research. Cases are identified through existing birth defects surveillance programs; controls are from vital records or birth hospital logs from the same catchment area. BD-STEPS uses a standardized computer-assisted telephone interview to collect information from case and control mothers on topics including demographics, health conditions, and medication use. Following the maternal interview, selected Centers request permission to sample residual newborn screening blood spots from state repositories for genetic analyses. New components planned for BD-STEPS include linkages with external datasets and use of online questionnaires to collect in-depth information on selected exposures.

RESULTS

BD-STEPS extends NBDPS by continuing to collect data on many exposures that were assessed in NBDPS, allowing data from both studies to be combined and providing an unprecedented sample size to analyze rare exposures. BD-STEPS expands upon NBDPS by collecting more detailed information on existing exposures as well as new exposures.

CONCLUSION

The goal of BD-STEPS is to provide women and healthcare providers with information they need to make decisions to promote the healthiest pregnancy possible.