title: Prolonged second stage of labor is associated with low Apgar score.
abstract: There is no consensus on the effects of a prolonged second stage of labor on neonatal outcomes. In this large Swedish population-based cohort study, our objective was to investigate prolonged second stage and risk of low Apgar score at 5 min. All nulliparous women (n = 32,796) delivering a live born singleton infant in cephalic presentation at ≥37 completed weeks after spontaneous onset of labor between 2008 and 2012 in the counties of Stockholm and Gotland were included. Data were obtained from computerized records. Exposure was time from fully retracted cervix until delivery. Logistic regression analyses were used to estimate crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Adjustments were made for maternal age, height, BMI, smoking, sex, gestational age, sex-specific birth weight for gestational age and head circumference. Epidural analgesia was included in a second model. The primary outcome measure was Apgar score at 5 min <7 and <4. We found that the overall rates of 5 min Apgar score <7 and <4 were 7.0 and 1.3 per 1000 births, respectively. Compared to women with <1 h from retracted cervix to birth, adjusted ORs of Apgar score <7 at 5 min generally increased with length of second stage of labor: 1 to <2 h: OR 1.78 (95% CI 1.19-2.66); 2 to <3 h: OR 1.66 (1.05-2.62); 3 to <4 h: OR 2.08 (1.29-3.35); and ≥4 h: OR 2.71 (1.67-4.40). We conclude that prolonged second stage of labor is associated with an increased risk of low 5 min Apgar score.
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, T2, Karolinska Institutet, 171 77, Stockholm, Sweden. maria.altman@ki.se.
authors.forename: Maria
authors.initials: M
authors.lastname: Altman
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, T2, Karolinska Institutet, 171 77, Stockholm, Sweden.|Division of Obstetrics and Gynecology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Sandström
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, T2, Karolinska Institutet, 171 77, Stockholm, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Petersson
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, T2, Karolinska Institutet, 171 77, Stockholm, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Frisell
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, T2, Karolinska Institutet, 171 77, Stockholm, Sweden.
authors.forename: Sven
authors.initials: S
authors.lastname: Cnattingius
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, T2, Karolinska Institutet, 171 77, Stockholm, Sweden.|Division of Obstetrics and Gynecology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Stephansson
mesh_terms: D000328:Adult; D001034:Apgar Score; D001238:Asphyxia Neonatorum / Q000453:epidemiology / Q000209:etiology; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D004420:Dystocia / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007748:Labor Stage, Second / Q000502:physiology*; D008423:Maternal Age; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000209:etiology; D010120:Oxytocics / Q000008:administration & dosage; D010121:Oxytocin / Q000008:administration & dosage; D010298:Parity; D011159:Population Surveillance; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D013548:Sweden; D055815:Young Adult
chemical_list: D010120:Oxytocics; D010121:Oxytocin
keywords: Asphyxia; Dystocia; Neonatal outcome; Prolonged labor