Elective Induction of Labor at 39 Weeks of Gestation: A Prospective Randomized Trial


Department of Obstetrics and Gynecology, School of Medicine, Kitasato University, 1–15-1 Kitasato, Sagamihara, Kanagawa 228–0829, Japan


Objective: To clarify the safety of elective induction of labor at 39 weeks of gestation.

Study design: Prospective randomized study.

Subjects and methods: Uncomplicated nulliparas (N = 194) were randomly assigned at 36 weeks of gestation. Labor was electively induced in 63 women at 39 weeks of gestation in the active management group (I group, N = 98). Spontaneous labor onset was expected with semi-weekly nonstress test (NST) and amniotic fluid index (AFI) by 42 weeks of gestation in the expectant group (E group, N = 96). Perinatal events were compared between the 2 groups.

Results: A significantly higher incidence of meconium-stained amnios (19.4% vs 3.2%) and fetal resuscitation (16.7% vs 4.8%) was found in the E group than in the 1 group. Also, although a significantly higher incidence of epidural analgesia was noted in the 1 group (89%) than in the E group (54%) (labor onset ≥ 39 weeks, N = 72), the duration of the 1st stage was shorter in 1 group and the duration of the 2nd stage was not significantly different. No other significant difference was noted between the 2 groups in terms of the rate of C-section, blood loss, incidence of pathological FHR, birth weight, Apgar score, umbilical arterial pH, or admission to NICU.

Conclusion: Active management of labor at 39 weeks could be made as safely as expectant management with modified biophysical profile monitoring.