Interpregnancy interval and prevalence of selected birth defects: A multistate study.

2021

2021 Oct 21

2472-1727

<p><strong>BACKGROUND: </strong>Both short and long interpregnancy intervals (IPIs) have been associated with adverse birth outcomes. We undertook a multistate study to describe the prevalence of selected birth defects by IPI.</p>

<p><strong>METHODS: </strong>We obtained data from nine population-based state birth defects registries for singleton live births in 2000-2009 among mothers with a previous live birth identified through birth certificates. IPI was calculated as the difference between prior birthdate and start of the current pregnancy (conception date). We estimated prevalence of selected defects per 10,000 live births and prevalence ratios (PRs) with 95% confidence intervals (CIs) overall and stratified by maternal age at previous birth and race/ethnicity. Primary analyses focused on short IPI &lt; 6 months and long IPI ≥ 60 months compared to 18-23 months (referent). Sensitivity analyses limited to active-surveillance states and those with&lt;10% missing IPI.</p>

<p><strong>RESULTS: </strong>Among 5,147,962 eligible births, 6.3% had short IPI while 19.8% had long IPI. Compared to referent, prevalence with short IPI was elevated for gastroschisis (3.7, CI: 3.0-4.5 vs. 2.0, CI: 1.6-2.4) and with both short and long IPI for tetralogy of Fallot (short: 3.4, 2.8-4.2 long: 3.8, 3.4-4.3 vs. 2.7, 2.3-3.2) and cleft lip ± palate (short: 9.9, 8.8-11.2 long: 9.2, 8.5-9.8 vs. 8.4, 7.6-9.2). Stratified analyses identified additional associations, including elevated prevalence of anencephaly with short IPI in younger mothers and limb defects with long IPI in those ages 25-34 at prior birth. Sensitivity analyses showed similar results.</p>

<p><strong>CONCLUSION: </strong>In this population-based study, we observed increased prevalence of several birth defects with short and long IPI.</p>

10.1002/bdr2.1960

Birth Defects Res

34676681

Short interpregnancy intervals and risks for birth defects: support for the nutritional depletion hypothesis.

2021

2021 Mar 01

1938-3207

<p><b>BACKGROUND: </b>Research suggests short interpregnancy intervals increase risks for adverse perinatal outcomes, including some birth defects. A hypothesized cause is nutritional depletion, including folic acid (FA).</p><p><b>OBJECTIVES: </b>We evaluated associations between short interpregnancy intervals, alone and in combination with FA intake, and the occurrence of select malformations.</p><p><b>METHODS: </b>Data were from the National Birth Defects Prevention Study (US case-control, 1997-2011). Participants included multiparous women whose prior pregnancy resulted in live birth. Cases included 8 noncardiac and 6 cardiac defect groups (n = 3219); controls were nonmalformed live-borns (n = 2508). We categorized interpregnancy interval (<6, 6-11, 12-17, and 18-23 mo) and periconceptional FA intake [no FA supplement use and dietary folate equivalents (DFE) <400 µg/d, no FA supplement use and DFE ≥400 µg/d, or any FA supplement use]. We controlled for age, race/ethnicity, income, pregnancy intention, and study center. ORs <0.8 or >1.2 were considered to represent potentially meaningful associations.</p><p><b>RESULTS: </b>ORs for <6 compared with 18-23 mo were >1.2 for 4/8 noncardiac and 3/6 cardiac malformations. Among participants with any FA supplement use, ORs comparing <6 with 6-23 mo were <1.2 for most defects. Conversely, most ORs were >1.2 for <6 mo + no FA supplement use and DFE <400 µg/d compared with 6-23 mo + any FA supplement use. Magnitude and precision varied by defect.</p><p><b>CONCLUSIONS: </b>Short interpregnancy intervals were associated with a trend of higher risks for several defects, notably in the absence of FA supplement use. To our knowledge, our study is the first to provide preliminary empirical support that these etiologies may be related to shorter interpregnancy intervals and possible nutritional deficiencies. Because FA intake is highly correlated with other nutrients, and because our estimates were generally imprecise, more research with larger sample sizes is needed to better understand the role of FA compared with other nutrients in each defect-specific etiology.</p>

10.1093/ajcn/nqaa436

Am J Clin Nutr

33668063