High- vs low-dose oxytocin regimens for labor augmentation: a systematic review and meta-analysis

OBJECTIVE: This study aimed to assess whether high- vs low-dose oxytocin regimens for labor augmentation are associated with differential risk of low Apgar score, neonatal acidosis, and other adverse labor outcomes. DATA SOURCES: We searched electronic databases (MEDLINE, Embase, the Cochrane Library, CINAHL, Scopus, ClinicalTrials.gov) from inception up to March 2024 using combinations of the following key words: “oxytocin,” “oxytocin regimen,” “oxytocin protocol,” “oxytocin dosage,” “active management,” “high dose protocol,” “low dose protocol,” and “augmentation of labor.” STUDY ELIGIBILITY CRITERIA: We included quasi-randomized and randomized controlled trials comparing continuous oxytocin infusion with high-dose regimens (intervention group) vs low-dose regimens (control group) in nulliparous or multiparous patients undergoing labor augmentation. High-dose regimens were defined as a starting oxytocin dose of ≥4 mU/min, increasing in increments of 3 to 7 mU/min every 15 to 40 minutes. Low-dose regimens were defined as a starting oxytocin dose of <4 mU/min, increasing in increments of 1 to 2 mU/min every 15 to 40 minutes (PROSPERO CRD42024500197). METHODS: The coprimary outcomes were incidence of Apgar score <7 at 5 minutes and umbilical arterial pH <7.00. The secondary outcomes included cesarean delivery and chorioamnionitis. We performed random-effects head-to-head meta-analyses to compare high-dose with low-dose strategies, and reported summary risk ratios with 95% confidence intervals. RESULTS: Ten randomized and quasi-randomized controlled trials of 5508 pregnancies met the inclusion criteria and were included in this meta-analysis. There was no difference in risk for the coprimary outcomes of Apgar score <7 at 5 minutes (relative risk, 0.94; 95% confidence interval, 0.60–1.46) and umbilical arterial pH <7.00 (relative risk, 0.77; 95% confidence interval, 0.50–1.20). There was also no difference in risk for cesarean delivery (relative risk, 0.83; 95% confidence interval, 0.67–1.02). High-dose oxytocin regimens were associated with significantly lower risk of chorioamnionitis (relative risk, 0.70; 95% confidence interval, 0.57–0.84; number needed to treat=25) and higher risk of tachysystole (relative risk, 1.32; 95% confidence interval, 1.21–1.43; P<.001). CONCLUSION: When used for labor augmentation, high-dose oxytocin regimens decreased the risk of chorioamnionitis compared with low-dose regimens without affecting the risk of low Apgar scores, neonatal acidosis, or cesarean delivery.