title: Does labor start too late?
abstract: To determine the optimal time of delivery, in terms of lowest risk of peripartum complications, the relative incidences of the parameters. Abnormal cardiotocogram (CTG), operative vaginal delivery, Apgar < 7 at 1 and 5 min, artery cord blood pH < 7.20, blood loss > 500 ml, epidural anesthesia, and Cesarean section, were retrospectively analysed with regard to mode of labor onset (spontaneous, induced) and gestational age in all deliveries between gestational weeks (GW) 35 + 0/7 and 42 + 6/7 from 1986 through 1993 at Zurich University Hospital (n = 11,834) and additionally with regard to birth weight in the same population from 1987 through 1993 (n = 10,346). The distribution of most parameters was parabolic with nadirs at GW 37-38; the incidence of low Apgar scores and Cesarean sections, however, was lowest nearer term (GW 39-40). Mode of labor onset had little effect (< or = 1 week) on the time of lowest incidence. The birth weight associated with the fewest complications was 3000 g, with the optimal time of delivery being GW 37-38, assuming a birth weight normal for gestational age.
authors.affiliation: Department of Obstetrics, University Hospital Zurich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Unger
authors.forename: R
authors.initials: R
authors.lastname: Zimmermann
authors.forename: A
authors.initials: A
authors.lastname: Huch
authors.forename: R
authors.initials: R
authors.lastname: Huch
mesh_terms: D000767:Anesthesia, Epidural; D001034:Apgar Score; D001724:Birth Weight; D015148:Cardiotocography; D002585:Cesarean Section; D005260:Female; D005312:Fetal Blood; D005865:Gestational Age; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007751:Labor, Induced; D007743:Labor, Obstetric; D011247:Pregnancy; D012189:Retrospective Studies; D013997:Time Factors