Interpregnancy Interval and Congenital Anomalies: A Record-Linkage Study Using the Manitoba Population Research Data Repository

Birth spacing and risk of adverse pregnancy and birth outcomes: A systematic review and dose-response meta-analysis

INTRODUCTION

The association between extreme birth spacing and adverse outcomes is controversial, and available evidence is fragmented into different classifications of birth spacing.

MATERIAL AND METHODS

We conducted a systematic review of observational studies to evaluate the association between birth spacing (i.e., interpregnancy interval and interoutcome interval) and adverse outcomes (i.e., pregnancy complications, adverse birth outcomes). Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using a random-effects model, and the dose-response relationships were evaluated using generalized least squares trend estimation.

RESULTS

A total of 129 studies involving 46 874 843 pregnancies were included. In the general population, compared with an interpregnancy interval of 18-23 months, extreme intervals (<6 months and ≥ 60 months) were associated with an increased risk of adverse outcomes, including preterm birth, small for gestational age, low birthweight, fetal death, birth defects, early neonatal death, and premature rupture of fetal membranes (pooled OR range: 1.08-1.56; p < 0.05). The dose-response analyses further confirmed these J-shaped relationships (pnon-linear  < 0.001-0.009). Long interpregnancy interval was only associated with an increased risk of preeclampsia and gestational diabetes (pnon-linear  < 0.005 and pnon-linear  < 0.001, respectively). Similar associations were observed between interoutcome interval and risk of low birthweight and preterm birth (pnon-linear  < 0.001). Moreover, interoutcome interval of ≥60 months was associated with an increased risk of cesarean delivery (pooled OR 1.72, 95% CI 1.04-2.83). For pregnancies following preterm births, an interpregnancy interval of 9 months was not associated with an increased risk of preterm birth, according to dose-response analyses (pnon-linear  = 0.008). Based on limited evidence, we did not observe significant associations between interpregnancy interval or interoutcome interval after pregnancy losses and risk of small for gestational age, fetal death, miscarriage, or preeclampsia (pooled OR range: 0.76-1.21; p > 0.05).

CONCLUSIONS

Extreme birth spacing has extensive adverse effects on maternal and infant health. In the general population, interpregnancy interval of 18-23 months may be associated with potential benefits for both mothers and infants. For women with previous preterm birth, the optimal birth spacing may be 9 months.

Short interpregnancy interval can lead to adverse pregnancy outcomes: A meta-analysis

BACKGROUND

The evidence of some previous papers was insufficient in studying the causal association between interpregnancy interval (IPI) and adverse pregnancy outcomes. In addition, more literature have been updated worldwide during the last 10 years.

METHODS

English and Chinese articles published from January 1980 to August 2021 in the databases of PubMed, Cochrane Library, Ovid, Embase, China Biology Medicine disc (CBM), and China National Knowledge Infrastructure (CNKI) were searched. Then following the inclusion and exclusion criteria, we screened the articles. Utilizing the Newcastle-Ottawa Scale (NOS), we evaluated the quality of the included articles. The literature information extraction table was set up in Excel, and the meta-analysis was performed with Stata 16.0 software (Texas, USA).

RESULTS

A total of 41 articles were included in the meta-analysis, and NOS scores were four to eight. The short IPI after delivery was the risk factor of preterm birth (pooled odds ratio 1.49, 95% confidence interval 1.42-1.57), very preterm birth (pooled OR: 1.82, 95% CI: 1.55-2.14), low birth weight (pooled OR: 1.33, 95% CI: 1.24-1.43), and small for gestational age (pooled OR: 1.14, 95% CI: 1.07-1.21), offspring death (pooled OR: 1.60, 95% CI: 1.51-1.69), NICU (pooled OR: 1.26, 95% CI: 1.01-1.57), and congenital abnormality (pooled OR: 1.10, 95% CI: 1.05-1.16), while was not the risk factor of gestational hypertension (pooled OR: 0.95, 95% CI: 0.93-0.98) or gestational diabetes (pooled OR: 1.06, 95% CI: 0.93-1.20).

CONCLUSION

Short IPI (IPI < 6 months) can lead to adverse perinatal outcomes, while it is not a risk factor for gestational diabetes and gestational hypertension. Therefore, more high-quality studies covering more comprehensive indicators of maternal and perinatal pregnancy outcomes are needed to ameliorate the pregnancy policy for women of childbearing age.

Interpregnancy interval and subsequent perinatal risk of congenital heart disease in Guangzhou, Southern China: a retrospective cohort study, 2014-2019

BACKGROUND

The association between maternal interpregnancy interval (IPI) and congenital heart disease (CHD) in neonates remains inconclusive. This study aimed to examine the effect of maternal IPI on birth risk of CHD.

METHODS

Chinese women with two consecutive singleton deliveries in Guangzhou between January 2014 and December 2019 were selected as participants. Information on IPI and CHD was extracted from the Guangzhou Perinatal Health Care and Delivery Registry and the Guangzhou Birth Defects Surveillance Program. We stratified IPI into four categories: <24 months, 24-35 months, 36-59 months, and ≥60 months. A multivariate logistic regression model was used to examine the association between IPI and CHD. Subgroup analysis was also performed to assess whether the associations differed across top three CHD subtypes.

RESULTS

For 119,510 women enrolled in this study, the mean ages at two consecutive deliveries were 26.2 ± 3.8 and 28.8 ± 4.0 years, which yielded a median IPI of 51.2 (interquartile range, 32.1-77.2) months. Among them, 828 delivered infants with CHD during their second pregnancy. There was a J-shaped curve relationship between IPI and CHD with the lowest birth prevalence (5.33‰) at 24-35-month interval. Compared to women with an IPI of 24-35 months, those with an IPI ≥60 had an increased risk of delivering infants with CHD (adjusted odds ratio (OR), 1.41; 95% confidence interval (CI), 1.19-1.64). However, for those with an IPI <24 months (adjusted OR, 1.24; 95% CI, 0.97-1.51), IPI was statistically insignificant associated with the risk of delivering infants with CHD (p = .12). There were different patterns of associations for different CHD subtypes.

CONCLUSIONS

Longer maternal IPI (≥60 months) was associated with an increased risk of delivering infants with CHD in the Chinese population.

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

BACKGROUND

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.

METHODS

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 < 6 months and long IPI ≥ 60 months compared to 18-23 months (referent). Sensitivity analyses limited to active-surveillance states and those with<10% missing IPI.

RESULTS

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.

CONCLUSION

In this population-based study, we observed increased prevalence of several birth defects with short and long IPI.

Short interpregnancy intervals and adverse perinatal outcomes in high-resource settings: An updated systematic review

BACKGROUND

This systematic review summarises association between short interpregnancy intervals and adverse perinatal health outcomes in high-resource settings to inform recommendations for healthy birth spacing for the United States.

METHODS

Five databases and a previous systematic review were searched for relevant articles published between 1966 and 1 May 2017. We included studies meeting the following criteria: (a) reporting of perinatal health outcomes after a short interpregnancy interval since last livebirth; (b) conducted within a high-resource setting; and (c) estimates were adjusted for maternal age and at least one socio-economic factor.

RESULTS

Nine good-quality and 18 fair-quality studies were identified. Interpregnancy intervals <6 months were associated with a clinically and statistically significant increased risk of adverse outcomes in studies of preterm birth (eg, aOR ≥ 1.20 in 10 of 14 studies); spontaneous preterm birth (eg, aOR ≥ 1.20 in one of two studies); small-for-gestational age (eg, aOR ≥ 1.20 in 5 of 11 studies); and infant mortality (eg, aOR ≥ 1.20 in four of four studies), while four studies of perinatal death showed no association. Interpregnancy intervals of 6-11 and 12-17 months generally had smaller point estimates and confidence intervals that included the null. Most studies were population-based and few included adjustment for detailed measures of key confounders.

CONCLUSIONS

In high-resource settings, there is some evidence showing interpregnancy intervals <6 months since last livebirth are associated with increased risks for preterm birth, small-for-gestational age and infant death; however, results were inconsistent. Additional research controlling for confounding would further inform recommendations for healthy birth spacing for the United States.

Interpregnancy Intervals in a Contemporary Manitoba Cohort: Prevalence of So-Called Suboptimal Intervals and Associated Maternal Characteristics

OBJECTIVE

Short and long interpregnancy intervals (IPIs) have been associated with various adverse outcomes, and a 2016 American College of Obstetricians and Gynecologists' Committee Opinion recommends an optimal IPI of 18 months to 5 years. Descriptive data on the IPI in Canada are lacking. The objective of this study was to examine IPIs in a Manitoba cohort.

METHODS

The study analyzed a subset of records from a larger dataset used to examine the IPI and adverse perinatal outcomes. For that study, Manitoba's Hospital Abstracts data were searched to identify births from 1985 to 2014. Each two consecutive live births to the same mother formed a sibling pair. The IPI was calculated as the interval between the two siblings' births, minus the younger sibling's GA. Information on maternal characteristics was extracted from various datasets housed in the Manitoba Population Research Data Repository. The current analysis examined second and higher-order births between 2010 and 2014. The proportion of suboptimal IPIs was determined and IPIs were cross-tabulated with birth year and maternal subgroups.

RESULTS

More than half of pregnancies were conceived following a suboptimal interval. IPIs of less than 6 months - which have been associated with the highest risk of adverse outcomes - were more prevalent among certain subgroups. These included younger women as well as women who received inadequate prenatal care, smoked or drank alcohol during pregnancy, were low income, or did not graduate from high school.

CONCLUSION

Suboptimal IPIs were common in this Manitoba cohort. Stakeholders should consider whether greater efforts to promote appropriate birth spacing are warranted.