Duration of labor among women with hypertensive disorders of pregnancy; A Swedish register cohort study

Roxanne Hastie; Lina Bergman; Tansim Akhter; Anna Sandström; Anna-Karin Wikström; Susanne Hesselman

doi:10.1016/j.ejogrb.2020.05.024

Duration of labor among women with hypertensive disorders of pregnancy; A Swedish register cohort study

Eur J Obstet Gynecol Reprod Biol. 2020 Aug:251:114-118. doi: 10.1016/j.ejogrb.2020.05.024. Epub 2020 May 20.

Authors

Roxanne Hastie¹, Lina Bergman², Tansim Akhter³, Anna Sandström⁴, Anna-Karin Wikström³, Susanne Hesselman⁵

Affiliations

¹ Mercy Perinatal, Mercy Hospital for Women, MelbourneAustralia; Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. Electronic address: hastie.r@unimelb.edu.au.
² Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden; Department of Obstetrics and Gynecology, Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, GothenburgSweden.
³ Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
⁴ Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden; Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden; Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, USA.
⁵ Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden; Center for Clinical Research, Uppsala University, Falun, Sweden.

PMID: 32497985
DOI: 10.1016/j.ejogrb.2020.05.024

Abstract

Objective: Preeclampsia is a severe obstetric complication affecting 2-8% of pregnancies. There is a common belief that women with preeclampsia experience a shorter duration of labor, where it is thought that increased inflammation that occurs with the disease facilitates labor. However, little evidence exists to support or refute this. Thus, we undertook a register-based cohort study investigating the association between hypertensive disorders of pregnancy and labor duration.

Study design: This was a Swedish register-based cohort study of nulliparous women with spontaneous or induced onset of labor at >34 weeks of gestation with a singleton fetus in cephalic presentation. Information of duration of labor was retrieved from electronic birth records and compared between women with hypertensive disorders and normotensives pregnancies. Data was represented as mean adjusted difference in hours (adjusted for pre-gestational disorders, maternal characteristics and mode of delivery) and adjusted hazard ratios (aHR), with an event defined as vaginal birth and women with intrapartum caesarean section censored. An aHR >1 indicated shorter duration of labor.

Results: Among 101,531 women, 5548 (5.5%) developed a hypertensive disorder of pregnancy. The overall mean duration of labor was 9.43 (SD 5.32) hours. Women with hypertensive disorders experienced a shorter duration of labor compared to normotensive women, with an adjusted mean difference of -0.68 h (95% CI -0.90, -0.47) for gestational hypertension and -1.53 h (95% CI -1.72, -1.35) for preeclampsia. This corresponded to an aHR of 1.05 (95% CI 1.01, 1.10) and 1.12 (95% CI 1.08, 1.17), respectively. However, when we confined the analysis to those who labored spontaneously, the presence of hypertensive disorders did not alter duration of labor (aHR 0.98, 95% CI 0.95,1.01). Only women who were induced and also had hypertensive disorders experienced a shorter duration of labor (aHR 1.07, 95% CI 1.04,1.09).

Conclusions: Hypertensive disorders did not alter labor duration among women with spontaneous onset of labor, however an association was observed among women who were induced.

Keywords: Birth; Hypertensive disorders of pregnancy; Labor duration; Labor onset.

MeSH terms

Cesarean Section
Cohort Studies
Female
Humans
Hypertension, Pregnancy-Induced* / epidemiology
Labor, Obstetric*
Pregnancy
Sweden / epidemiology