Association between interpregnancy interval and pregnancy complications by history of complications: a population-based cohort study

Abstract

ObjectiveTo examine if the association between interpregnancy interval (IPI) and pregnancy complications varies by the presence or absence of previous complications.Design and settingPopulation-based longitudinally linked cohort study in Western Australia (WA).ParticipantsMothers who had their first two (n=252 368) and three (n=96 315) consecutive singleton births in WA between 1980 and 2015.Outcome measuresWe estimated absolute risks (AR) of preeclampsia (PE) and gestational diabetes (GDM) for 3–60 months of IPI according to history of each outcome. We modelled IPI using restricted cubic splines and reported adjusted relative risk (RRs) with 95% CI at 3, 6, 12, 24, 36, 48 and 60 months, with 18 months as reference.ResultsRisks of PE and GDM were 9.5%, 2.6% in first pregnancies, with recurrence rates of 19.3% and 41.5% in second pregnancy for PE and GDM, respectively. The AR of GDM ranged from 30% to 43% across the IPI range for mothers with previous GDM compared with 2%–8% for mothers without previous GDM. For mothers with no previous PE, greater risks were observed for IPIs at 3 months (RR 1.24, 95% CI 1.07 to 1.43) and 60 months (RR 1.40, 95% CI 1.29 to 1.53) compared with 18 months. There was insufficient evidence for increased risk of PE at shorter IPIs of <18 months for mothers with previous PE. Shorter IPIs of <18 months were associated with lower risk than at IPIs of 18 months for mothers with no previous GDM.ConclusionsThe associations between IPIs and risk of PE or GDM on subsequent pregnancies are modified by previous experience with these conditions. Mothers with previous complications had higher absolute, but lower RRs than mothers with no previous complications. However, IPI remains a potentially modifiable risk factor for mothers with previous complicated pregnancies.

Association of interpregnancy interval with adverse pregnancy outcomes according to the outcomes of the preceding pregnancy: a longitudinal study with 4.7 million live births from Brazil

“…Our findings align with previous studies assessing various perinatal outcomes, 17 , 18 , 19 , 20 , 21 , 34 confirming the J-shaped relationship between IPI and birth outcomes and reinforcing the increased likelihood of repeating adverse outcomes in subsequent pregnancies, particularly as the number of previous outcomes increases. This latter finding is consistent with the hypothesis of distinct vulnerable newborn phenotypes, which can exhibit varying risks for adverse outcomes based on combinations of prematurity, birth weight, and weight adequacy for gestational age.…”

“…However, it remains unclear whether IPI length affects adverse birth outcomes similarly in women with a history of prior adverse perinatal outcomes compared to those without such history. Some studies 16 , 17 , 18 , 19 , 20 , 21 have suggested a potential change in this association for different maternal and infant outcomes depending on the maternal history of prior adverse outcomes. However, most of these studies were conducted in high-income countries with small sample sizes, which raises concerns about the applicability of their results to low- and middle-income countries, where healthcare access, maternal exposures, and disease profiles may vary significantly.…”

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

“…To date, IPI has been among the most studied birth spacing intervals. Previous studies have reported on J‐shaped dose–response relationships between IPI and the risk of adverse outcomes (eg gestational diabetes mellitus [GDM], low birthweight [LBW], preterm birth [PTB], and small for gestational age [SGA]) 8‐10 . Moreover, subsequent pregnancies after live birth or pregnancy loss have been variably associated with adverse pregnancy and birth outcomes 11,12 .…”

“…Previous studies have reported on J‐shaped dose–response relationships between IPI and the risk of adverse outcomes (eg gestational diabetes mellitus [GDM], low birthweight [LBW], preterm birth [PTB], and small for gestational age [SGA]). 8 , 9 , 10 Moreover, subsequent pregnancies after live birth or pregnancy loss have been variably associated with adverse pregnancy and birth outcomes. 11 , 12 Short intervals after a pregnancy loss might prevent adverse outcomes, including PTB, LBW, SGA, and recurrent preeclampsia.…”

Understanding women’s views of and preferences for accessing postpartum contraception: a qualitative evidence synthesis

“…Younger women, and women from low socioeconomic areas, are more likely to have shorter IPIs 8 9 11. Short IPIs are associated with increased rates of perinatal, obstetric and neonatal complications,10–15 and increased rates of adverse outcomes in subsequent pregnancies 12. Short IPIs are also associated with increased psychosocial strain on the family and poorer behavioural and cognitive outcomes for prior children 16…”