Long interpregnancy interval and mode of delivery

Area of Science:

• Obstetrics and Gynecology
• Reproductive Health
• Maternal-Fetal Medicine

Background:

• The World Health Organization (WHO) recommends a minimum interpregnancy interval (IPI) of 24 months to reduce adverse maternal and perinatal outcomes.
• Longer interpregnancy intervals, exceeding 59 months, have been suggested to potentially impact maternal and perinatal health, but their specific effects on labor and delivery, particularly cesarean delivery rates, remain less understood.

Purpose of the Study:

• To compare the cesarean delivery rate among primiparous women with a long interpregnancy interval (IPI) (>59 months) against primiparous women with an ideal minimum IPI (18-24 months) and nulliparous women.
• To investigate the influence of a long IPI on labor duration and cesarean delivery risk.

Main Methods:

• A retrospective cohort study was conducted over 17 years, including nulliparous and primiparous women delivering singleton, cephalic fetuses after 22 weeks of gestation.
• Women with IPIs <18 months or 24-59 months, and those with planned cesarean deliveries, were excluded. Three groups were analyzed: primiparous women with long IPI (>59 months), primiparous women with ideal IPI (18-24 months), and nulliparous women.

Main Results:

• The study included 18,503 women: 1342 in the long IPI group, 1388 in the ideal IPI group, and 15,773 in the nulliparous group.
• The cesarean delivery rate was significantly higher in the long IPI group (12.2%) compared to the ideal IPI group (6.3%) (aOR=2.2; 95% CI 1.6-3.1).
• Primiparous women with a long IPI had a lower cesarean rate (12.2%) than nulliparous women (14.3%) (aOR=0.5; 95% CI 0.4-0.7), with nulliparous women experiencing longer labor durations.

Conclusions:

• Primiparous women with a long interpregnancy interval (>59 months) face an elevated risk of cesarean delivery during labor when compared to those with an ideal minimum IPI (18-24 months).
• Conversely, primiparous women with a long IPI demonstrated a reduced rate of cesarean delivery compared to nulliparous women. Labor durations were comparable between the long and ideal IPI groups.