Interpregnancy intervals and maternal and neonatal outcomes: A retrospective cohort study

Despite numerous studies on the optimal timing for planning a safe pregnancy, the impact of the interval between pregnancies on birth outcomes remains debatable. The aim of this study was to determine the association between early interpregnancy intervals (IPIs) ranging from 0 to 35 months and maternal and neonatal outcomes.

We conducted a retrospective cohort study involving 6764 multiparous women who gave birth between January and December 2022 at two secondary-level maternity hospitals under the Ministry of Health of the Kyrgyz Republic. We investigated IPIs (0-5, 6-11, 12-17, 18-23 [control group], and 24-35 months) in relation to maternal, perinatal, and neonatal outcomes.

Maternal morbidity affected 14.9% of all women. The highest risk of maternal morbidity was observed at IPIs of 6-11 months (adjusted odds ratio [aOR] 2.634; 95% confidence interval [CI] 1.887-3.002) and 24-35 months (aOR 2.562; 95% CI 2.129-3.459). Mothers with short IPIs had higher odds of severe anemia (0-5 months: aOR 5.615, 95% CI 1.386-22.752; 6-11 months: aOR 2.812, 95% CI 1.007-5.891). Short IPIs were associated with higher odds of preterm birth (PTB), particularly extremely PTB (0-5 months: aOR 4.968, 95% CI 2.075-15.892; 6-11 months: aOR 4.024, 95% CI 2.361-8.452). In contrast, for an IPI of 24-35 months, the risk of extreme PTB was not statistically significant (aOR 1.110; 95% CI 0.714-2.463).

Short IPIs are significantly associated with increased risks of adverse maternal and neonatal outcomes. These findings emphasize the importance of optimal birth spacing and the need for enhanced postpartum family planning services to mitigate risks such as severe anemia and PTB.