Open AccessPregnancy risk increases from 41 weeks of gestation
Author(s) -
Nakling Jakob,
Backe Bjørn
Publication year - 2006
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1080/00016340500543733
Subject(s) - medicine , obstetrics , relative risk , gestation , confidence interval , pregnancy , gestational age , apgar score , population , prospective cohort study , neonatal intensive care unit , gynecology , pediatrics , surgery , environmental health , biology , genetics
Background. The aim of this study was to evaluate the mortality and morbidity of conservatively managed post‐term pregnancies (gestation 294 days and beyond). Materials and methods. This is a population‐based prospective study. The sample was comprised of all women ( N =17 493) with a singleton pregnancy in one Norwegian county from 1989 to 1999, with a second‐trimester ultrasound examination and delivery after 37 completed gestational weeks. Results. One thousand three hundred and thirty‐six (7.6%) of the deliveries were post‐term. In this group, the increase in perinatal mortality reached borderline significance [relative risk (RR) 2.0; 95% confidence interval 0.9–4.6]. Perinatal morbidity expressed as Apgar score <7 at 5min (RR 2.0; 95% confidence interval 1.2–3.3), and transferal to neonatal intensive care unit (RR 1.6; 95% confidence interval 1.3–2.0) were significantly more frequent. However, RR for perinatal death calculated per 1000 ongoing pregnancies increased significantly from 0.2 in week 37–3.7 in week 42, using perinatal mortality in gestational week 41 as a reference. Conclusions Our results indicate that expectant management of post‐term pregnancies allowing pregnancies to continue up to week 43 carries a risk for perinatal mortality and morbidity. The risk increases already from gestational week 41. The guidelines for management of post‐term pregnancies should be revised.