Prolonged Second Stage of Labor Does Not Shorten Gestation in the Next Pregnancy

Women whose first labor included a prolonged second stage do not deliver earlier in their next pregnancy, according to a retrospective cohort study conducted at Shamir Medical Center and published in BMC Pregnancy and Childbirth. The finding addresses a long-standing concern that extended pressure of the fetal head on the cervix during a first delivery might weaken cervical tissue and raise the risk of preterm birth later.

The researchers set out to evaluate the impact of a prolonged second stage of labor on gestational age at delivery in a subsequent pregnancy. Their motivation rests on a hypothesis described in the study’s background: a history of preterm birth is one of the main risk factors for delivering before 37 weeks again, and it has been suggested that prolonged pressure of the fetal head during the first delivery may affect the integrity and strength of cervical tissue, potentially leading to preterm birth in the next pregnancy.

The study reviewed records from January 1, 2017, to March 1, 2023. It included 3,017 primiparous women with a term singleton pregnancy whose first delivery was a vertex, spontaneous, non-instrumental vaginal delivery, and who went on to have a subsequent singleton delivery at the same institution. Women whose first delivery was by cesarean, an instrumental vaginal delivery, a twin gestation, or a non-vertex presentation were excluded.

The primary outcome was gestational age at delivery in the subsequent pregnancy. The investigators stratified their analyses by the duration of the second stage of labor, comparing women whose second stage lasted less than three hours with those whose second stage lasted three hours or more.

Because the two groups differed in ways that could themselves influence gestational age, the team assessed and compared potential confounders, including maternal age, neonatal birthweight, and the use of regional anesthesia. Women in the shorter second-stage group were older and had infants with higher birthweight, whereas epidural labor analgesia was more frequent in the prolonged second-stage group.

Against that backdrop, the central result was clear: the difference in gestational age at delivery in the subsequent pregnancy between the two groups was small. The study’s conclusion states that, among women whose first delivery was vaginal and non-instrumental, a prolonged second stage of labor is not associated with a reduction in gestational age at delivery in the next pregnancy.

The authors frame this as a suggestion rather than a definitive causal verdict. As a retrospective, single-institution cohort restricted to women with a specific first-delivery profile, the study cannot establish causation, and its findings apply only to the population studied: primiparous women with term singleton vertex deliveries who returned to the same center for their next birth. Confounders such as maternal age, birthweight, and epidural use were assessed, but the groups were not randomized, so residual differences between them cannot be ruled out.

The data indicate that a prolonged second stage, at least as defined here by a threshold of three hours, was not followed by earlier delivery in the next pregnancy among the women studied. The article was published on October 27, 2026, as an open-access research paper, and the version shared carries a permanent DOI while remaining subject to final editorial edits by the journal.

Subject of Research: The effect of a prolonged second stage of labor in a first delivery on gestational age at delivery in the next pregnancy

Article Title: Duration of the second stage of labor in the first delivery and gestational age at delivery in the next pregnancy

Article References: Zlotin, M. P., Ben-Basat, N., Moskovich, M., Tal, A., Betser, M., Melcer, Y., Kovo, M., Maymon, R., & Jauniaux, E. (2026). Duration of the second stage of labor in the first delivery and gestational age at delivery in the next pregnancy. BMC Pregnancy and Childbirth. https://doi.org/10.1186/s12884-026-09883-8

Image Credits: AI Generated

DOI: 10.1186/s12884-026-09883-8

Keywords: second stage of labor, preterm birth, gestational age, retrospective cohort study, cervical integrity, subsequent pregnancy, vaginal delivery, obstetrics, Shamir Medical Center, BMC Pregnancy and Childbirth, Duration, second