Comparison of oxytocin use between singleton and twin pregnancies during induction of labor: A multicenter...

To compare the oxytocin doses used during induction, relative to the number of labor hours, between singleton and twin pregnancies.

We conducted a retrospective case-control study in two tertiary referral centers in France. Women with twin pregnancies who underwent labor induction with oxytocin in each center were eligible. Matching between cases (twin pregnancies) and controls (singleton pregnancies) was based on age, parity, gestational age, body mass index, and Bishop's score. We performed both univariate and multivariate analyses. The primary outcome was the total dose of oxytocin per hour (mIU/h). Secondary outcome included the maximum oxytocin infusion rate (mIU/min).

A total of 400 women were included in the study: 200 women with twin pregnancies were matched with 200 women with singleton pregnancies. In univariate analysis, the total oxytocin dose per hour was significantly higher in the twin pregnancy group compared to the singleton group (360 mIU/h vs. 305 mIU/h, p = 0.01). Significant differences were also found for the secondary outcome: 10 mUI/min in the cases group and 8 mUI/min in the control group (p = 0.03). After adjustment, multivariate analysis showed that twin pregnancies were significantly associated with a higher total oxytocin dose per hour during induction (aOR: 1.95, 95 % CI [2.08, 5.32], p = 0.03).

In our study, women with twin pregnancies received significantly higher oxytocin doses during labor induction compared to women with singleton pregnancies. These findings suggest that oxytocin protocols for twin pregnancies may require specific adaptation.