title: Recurrence rate and outcome of postterm pregnancy, a national cohort study.
abstract: OBJECTIVE
  To assess the recurrence rate of postterm delivery (gestational age at or beyond 42+0 weeks or 294 days) and to describe maternal and perinatal outcomes after previous postterm delivery.
  
  
  METHODS
  From the longitudinal linked Netherlands Perinatal Registry database, we selected all singleton primiparous women who delivered between 37+0 and 42+6 weeks with a subsequent singleton pregnancy from 1999 to 2007. We excluded congenital abnormalities. We compared the recurrence rate of postterm delivery and risk of antenatal fetal death in women with and without a postterm delivery in their first pregnancy. We compared perinatal outcome (composite of perinatal mortality, Apgar score <7 and birth injury) and adverse maternal outcome (composite of maternal death, abruptio placentae, PPH>1000ml and blood transfusions) between women with a recurrent and a de novo postterm second pregnancy.
  
  
  RESULTS
  Our study population consisted of 233,327 women of whom 17,874 (7.7%) delivered postterm in the first pregnancy. In the second pregnancy, 2678 (15%) women had a recurrent postterm delivery compared to 8698 (4%) women with a de novo postterm delivery (odds ratio (OR) 4.2 95% confidence interval (CI) 4.0-4.4). Subgroup analysis in recurrent and de novo postterm delivery showed no differences in composite perinatal and composite maternal outcome (OR 1.0; CI 0.7-1.5, p=0.90 and OR 1.1, CI 0.9-1.4, p=0.16), adjusted for fetal position and mode of delivery).
  
  
  CONCLUSIONS
  Women with a postterm delivery in the first pregnancy have a higher risk of recurrent postterm delivery. Our data suggest that there is no difference in the composite adverse perinatal outcome between recurrent and de novo postterm delivery.
authors.affiliation: Radboud University Medical Center, Nijmegen, Department of Obstetrics & Gynaecology, Nijmegen, The Netherlands; Academic Medical Center, University of Amsterdam, Department of Obstetrics and Gynaecology, Amsterdam, The Netherlands; Rijnstate Hospital, Department of Obstetrics and Gynaecology, Arnhem, The Netherlands. Electronic address: Joep.Kortekaas@radboudumc.nl.
authors.forename: Joep C
authors.initials: JC
authors.lastname: Kortekaas
authors.affiliation: Academic Medical Center, University of Amsterdam, Department of Obstetrics and Gynaecology, Amsterdam, The Netherlands.
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Kazemier
authors.affiliation: Academic Medical Center, University of Amsterdam, Department of Medical informatics, Amsterdam, The Netherlands.
authors.forename: Anita C J
authors.initials: AC
authors.lastname: Ravelli
authors.affiliation: Rijnstate Hospital, Department of Obstetrics and Gynaecology, Arnhem, The Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: de Boer
authors.affiliation: Radboud University Medical Center, Nijmegen, Department of Obstetrics & Gynaecology, Nijmegen, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van Dillen
authors.affiliation: The Robinson Institute | School of Paediatrics and Reproductive Health, University of Adelaide, 5000 SA, Australia.
authors.forename: BenWillem
authors.initials: B
authors.lastname: Mol
authors.affiliation: Academic Medical Center, University of Amsterdam, Department of Obstetrics and Gynaecology, Amsterdam, The Netherlands.
authors.forename: Esteriek
authors.initials: E
authors.lastname: de Miranda
mesh_terms: D000037:Abruptio Placentae / Q000453:epidemiology; D000328:Adult; D001034:Apgar Score; D001720:Birth Injuries / Q000453:epidemiology; D001803:Blood Transfusion / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D046689:Fetal Mortality; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008428:Maternal Mortality; D009426:Netherlands / Q000453:epidemiology; D054238:Perinatal Mortality; D006473:Postpartum Hemorrhage / Q000453:epidemiology; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011273:Pregnancy, Prolonged / Q000453:epidemiology*; D012008:Recurrence; D012042:Registries; D055815:Young Adult
keywords: Perinatal and maternal outcome; Perinatal death; Postterm pregnancy; Recurrence rate