Interpregnancy Interval and Subsequent Severe Maternal Morbidity: A 16-Year Population-Based Study From California

Abstract

Interpregnancy interval (IPI) associates with adverse perinatal outcomes, but its contribution to severe maternal morbidity (SMM) remains unclear. We examined the association between IPI and SMM, using data linked across sequential pregnancies to women in California 1997-2012. Adjusting for confounders measured at the index pregnancy (i.e. the first in a pair of consecutive pregnancies), we estimated adjusted risk ratios (aRRs) of SMM related to the subsequent pregnancy. We further conducted within-mother comparisons and analyses stratified by parity and maternal age at the index pregnancy. Compared to 18-23 months, IPI<6 months had same risk for SMM in between-mother comparison (aRR=0.96, 95%CI 0.91, 1.02) but lower risk in within-mother comparison (aRR=0.76, 95% confidence interval (CI) 0.67, 0.86). IPI 24-59 months and IPI≥60 months associated with increased risk of SMM in both between-mother (aRR=1.18, 95%CI 1.13, 1.23 and aRR=1.76, 95% CI 1.68, 1.85 respectively) and within-mother comparisons (aRR=1.22, 95%CI 1.11, 1.34 and aRR=1.88, 95% CI 1.66, 2.13 respectively). The association between IPI and SMM did not substantially differ by maternal age and parity. Longer IPI was associated with increased risk of SMM, which may be partly attributed to interpregnancy health.

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

“…After subsequently reading the title and abstract, the researchers excluded 1,324 articles. Finally, a total of 41 articles ( 1 – 3 , 13 – 50 ) were included ( Supplementary Table 2 ) in the meta-analysis after further reading the full text. Supplementary Table 1 showed the characteristics of the excluded studies.…”

“…Five studies ( 17 , 37 , 41 , 45 , 50 ) have reported the association between short IPI and comprehensive indicators of maternal morbidity. Stamilio et al ( 17 ) defined the main incidence indicators as any one or more of the following symptoms: uterine rupture, bladder, ureter or intestinal injury, and uterine artery tear.…”

“…De Silva and Thoma ( 45 ) analyzed severe maternal morbidity, which included maternal transfusion, admission to intensive care unit, ruptured uterus, and third- or fourth-degree perineal laceration. Liu et al ( 50 ) analyzed severe maternal morbidity with about 21 indicators of ICD-9. Due to methodological heterogeneity in the indicators’ definition of maternal morbidity in these studies, quantitative combinations were not included.…”

The association between the interdelivery interval and early postpartum urinary incontinence in women who had consecutive vaginal deliveries: a retrospective cohort study

“…The short IDI is associated with a number of adverse maternal-fetal outcomes (15)(16)(17)(18). Preterm birth, pregnancy complications, and maternal-fetal mortality are often the primary factors affecting the timing of the next delivery (18,19), while pelvic floor disorders (e.g., postpartum UI) are often overlooked.…”

An assessment of postpartum contraception rates with evolving care during the COVID-19 pandemic

“…Postpartum provision of contraception prevents short interpregnancy intervals, which have been associated with preterm birth and severe maternal and neonatal morbidity. [1] , [2] Half of short interpregnancy interval births in the United States are unintended. [3] , [4] At six weeks postpartum, all contraceptive options are deemed safe, including combined oral, vaginal, and transdermal contraceptives, oral or injectable progesterone, progesterone and copper IUDs, and contraceptive implants.…”