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.