Acta Obstet Gynecol Scand. 2006;85(11):1338-41.
Prenatal risk indicators of a prolonged pregnancy. The Danish Birth
Cohort 1998-2001.
Olesen AW, Westergaard JG, Olsen J.
Department of Gynaecology and Obstetrics, Odense University Hospital,
Odense, Denmark. a.w.olesen@stofanet.dk
Background:
Few prenatal risk factors of prolonged pregnancy, a
pregnancy of 42 weeks or more, are known. The objective was to examine
whether sociodemographic, reproductive, toxicologic, or medical health
conditions were associated with the risk of prolonged pregnancy.
Methods:
Data from the Danish Birth Cohort in Denmark were used.
Interview data from 53,392 participants with live-born singleton
deliveries in the period 1998-2001 were available at the time of this
study. The participants were interviewed by telephone at 12 and 30
weeks' gestation, and 6 and 18 months after delivery. Statistical
analyses were done using logistic regression.
Results:
Women with a
pre-pregnancy body mass index of 25 kg/m2 or more had a high risk of
prolonged pregnancy. If the pre-pregnancy body mass index was 35 kg/m2
or more the odds ratio was 1.52 (95% CI 1.28-1.82). Nulliparity also
increased the risk of prolonged pregnancy (OR (95% CI) = 1.35
(1.27-1.44)).
Conclusions:
The risk of post-term delivery was high in
women with a pre-pregnancy body mass index of 25 kg/m2 or more, and in
nulliparous women.

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