Outcomes of women presenting in active versus latent phase of spontaneous labor.

OBJECTIVE: To evaluate outcome differences between women presenting in latent and active labor.
METHODS: We evaluated all low-risk women with term, singleton, vertex gestations who presented in active phase or latent phase labor at MetroHealth Medical Center from January 1993 to June 2001. Baseline characteristics were compared. Labor outcomes were assessed by logistic regression, controlling for parity.
RESULTS: A total of 6,121 active phase and 2,697 latent phase women met the study criteria. More latent phase women were nulliparous (51 compared with 28%). Latent phase women had more cesarean deliveries (nulliparas 14.2% compared with 6.7%, multiparas 3.1% compared with 1.4%). Controlling for parity, latent phase women had more active phase arrest (odds ratio [OR] 2.2), oxytocin use (OR 2.3), scalp pH performed (OR 2.2), intrauterine pressure catheter placed (OR = 2.2), fetal scalp electrocardiogram monitoring (OR = 1.7), and amnionitis (OR 2.7) (P < .001 for each).
CONCLUSION: It is uncertain whether inherent labor abnormalities resulted in latent phase presentation and subsequent physician intervention or early presentation and subsequent physician intervention are the cause of labor abnormalities.