TY - JOUR
T1 - Interpregnancy Interval and Subsequent Severe Maternal Morbidity
T2 - A 16-Year Population-Based Study from California
AU - Liu, Can
AU - Snowden, Jonathan M.
AU - Lyell, Deirdre J.
AU - Wall-Wieler, Elizabeth
AU - Abrams, Barbara
AU - Kan, Peiyi
AU - Stephansson, Olof
AU - Lyndon, Audrey
AU - Carmichael, Suzan L.
N1 - Funding Information:
This work was funded by the National Institute of Nursing Research, National Institutes of Health (grant NR017020).
Publisher Copyright:
© 2021 The Author(s).
PY - 2021/6/1
Y1 - 2021/6/1
N2 - Interpregnancy interval (IPI) is associated 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 during 1997-2012. Adjusting for confounders measured in the index pregnancy (i.e., the first in a pair of consecutive pregnancies), we estimated adjusted risk ratios for 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 with an IPI of 18-23 months, an IPI of <6 months had the same risk for SMM in between-mother comparisons (adjusted risk ratio (aRR) = 0.96, 95% confidence interval (CI): 0.91, 1.02) but lower risk in within-mother comparisons (aRR = 0.76, 95% CI: 0.67, 0.86). IPIs of 24-59 months and ≥60 months were 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 (aRR = 1.22 (95% CI: 1.11, 1.34) and aRR = 1.88 (95% CI: 1.66, 2.13), respectively) comparisons. The association between IPI and SMM did not vary substantially by maternal age or parity. In this study, longer IPI was associated with increased risk of SMM, which may be partly attributed to interpregnancy health.
AB - Interpregnancy interval (IPI) is associated 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 during 1997-2012. Adjusting for confounders measured in the index pregnancy (i.e., the first in a pair of consecutive pregnancies), we estimated adjusted risk ratios for 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 with an IPI of 18-23 months, an IPI of <6 months had the same risk for SMM in between-mother comparisons (adjusted risk ratio (aRR) = 0.96, 95% confidence interval (CI): 0.91, 1.02) but lower risk in within-mother comparisons (aRR = 0.76, 95% CI: 0.67, 0.86). IPIs of 24-59 months and ≥60 months were 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 (aRR = 1.22 (95% CI: 1.11, 1.34) and aRR = 1.88 (95% CI: 1.66, 2.13), respectively) comparisons. The association between IPI and SMM did not vary substantially by maternal age or parity. In this study, longer IPI was associated with increased risk of SMM, which may be partly attributed to interpregnancy health.
KW - birth interval
KW - cohort studies
KW - interpregnancy interval
KW - longitudinal studies
KW - maternal health
KW - severe maternal morbidity
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U2 - 10.1093/aje/kwab020
DO - 10.1093/aje/kwab020
M3 - Article
C2 - 33543241
AN - SCOPUS:85107390416
SN - 0002-9262
VL - 190
SP - 1034
EP - 1046
JO - American Journal of Epidemiology
JF - American Journal of Epidemiology
IS - 6
ER -