Induction of labor in women with a history of fast labor.

Objective: History of fast labor is currently subjectively defined and inductions for non-medical indications are becoming restricted. We hypothesized that women induced for a history of fast labor do not have faster previous labors and do not deliver more quickly.

Methods: A retrospective case-control cohort design studied multiparas undergoing elective induction at one high risk center. Outcomes of dyads electively induced for a history of previous fast labor indication (PFast) were compared to controls with a psychosocial indication.

Results: A total of 612 elective inductions with 1074 previous deliveries were evaluated: 81 (13%) PFast and 531 (87%) control. PFast had faster previous labors (median 5.5 h, IQR: 4.5-6) versus. control (10 h, IQR: 9-10.5; p < 0.001). Subsequent delivery time from start to expulsion was shorter for PFast (median 7 h, IQR: 5-9, p < 0.001) than controls with and without a previous labor <5.5 h (8.6 h, IQR: 6-14 and 9.5 h, IQR: 7-15, respectively). PFast were less likely to have a serious maternal complication. Neonatal complications were similar.

Conclusions: Patients induced for a history of fast labor do have faster previous labors, suggesting a significant history of fast labor can be defined as <5.5 h. These women deliver more quickly and with lower morbidity than controls when subsequently induced, therefore the benefit may warrant the risk for a select number of women with a history of a prior labor length <5.5 h.