Differences in women presenting in latent and active phase of labor

Abstract

Women presenting in latent phase are at increased risk for Cesarean (CD) than those presenting in active phase. We sought to evaluate patient, labor, management and outcome differences between those presenting in latent phase and active phase. We evaluated all low-risk singleton, term women with vertex presentations, presenting in active phase (AP: contractions with or without ROM > = 4 cm) or latent phase (LP: contractions with or without ROM <4 cm or ROM only) delivering at MetroHealth Medical Center between January 1993 and June 2001. Women with a prior CD, or contraindication to labor or vaginal delivery were excluded, as were those with medical/obstetric complications or substance abuse. AP and LP gravidas were compared for baseline characteristics. Labor outcomes were assessed by logistic regression, controlling for parity. P<0.01 considered significant. OR = Odds ratio. 11,176 of 25,998 singleton gestations (43%) met our strict inclusion criteria: 6,744 AP and 4,432 LP gravidas. LP women were more likely nulliparous (57 vs. 33%), had smaller infants (3316 vs 3365 g), had more private insurance (26 vs 23%), p<0.0001 for each. Maternal race, age, weight, gestation at delivery were not different. LP women were at increased risk for CD (nulliparas: 15.7 vs 7.8%, multiparas; 3.7 vs 1.7, p<0.0001 for each). LP women had more prolonged latent phase (OR = 5.6), active phase arrest (OR = 2.2), and had more oxytocin use (OR = 3.1) scalp pH (OR = 2.0), IUPC (OR = 2.5) and ECG (OR = 1.8) monitoring performed, p < 0.001 for each, but not more CDs for arrest of descent. LP women had more amnionitis (OR 2.6) and postpartum infection (OR = 2.0) but not operative vaginal delivery, postpartum hemorrhage or need for neonatal intubation. Arriving in latent phase may be a marker for labor abnormalities in active phase unrelated to maternal or fetal characteristics. Whether these labor abnormalities cause or result from early presentation or subsequent physician intervention remains unresolved.