%0 Journal Article
%T Association between interpregnancy interval and the labor curve.
%A Burd J
%A Woolfolk C
%A Frolova A
%A Zofkie A
%A Odibo A
%A Carter EB
%A Kelly JC
%A Cahill AG
%A Raghuraman N
%J Am J Obstet Gynecol MFM
%V 6
%N 8
%D 2024 Aug 11
%M 38996916
%F 8.679
%R 10.1016/j.ajogmf.2024.101425
%X <B>BACKGROUND: </B>Both short and long interpregnancy intervals are associated with adverse pregnancy outcomes; however, the impact of interpregnancy intervals on labor progression is unknown.<BR><B>OBJECTIVE: </B>We examined the impact of interpregnancy intervals on the labor curve, hypothesizing that those with a longer interpregnancy intervals would have slower labor progression.<BR><B>METHODS: </B>This is a retrospective cohort study of patients with a history of one prior vaginal delivery admitted for induction of labor or spontaneous labor with a singleton gestation ≥37 weeks at an academic medical center between 2004 and 2015. Repeated measures regression was used to construct labor curves, which were compared between patients with short interpregnancy intervals, defined as <3 years since the last delivery, and long interpregnancy intervals, defined as >3 years since the last delivery. We chose this interval as it approximates the median birth interval in the United States. Interval-censored regression was used to estimate the median duration of labor after 4 centimeters of dilation, stratified by type of labor (spontaneous vs induced). Multivariate analysis was used to adjust for potential confounders.<BR><B>RESULTS: </B>Of the 1331 patients who were included in the analysis, 544 (41%) had a long interpregnancy interval. Among the entire cohort, there were no significant differences in first or second-stage progression between short and long interpregnancy interval groups. In the stratified analysis, first-stage progression varied between groups on the basis of labor type: long interpregnancy interval was associated with a slower active phase among those being induced and a quicker active phase among those in spontaneous labor. The second-stage duration was similar between cohorts regardless of labor type.<BR><B>CONCLUSIONS: </B>Multiparas with an interpregnancy interval >3 years may have a slower active phase than those with a shorter interpregnancy interval when undergoing induction of labor. Interpregnancy interval does not demonstrate an effect on the length of the second stage.