Risk factors and adverse pregnancy outcomes among births affected by velamentous umbilical cord insertion: a retrospective population-based register study.

OBJECTIVE: To identify risk factors associated with velamentous cord insertion (VCI) and to evaluate the association between adverse pregnancy outcomes and VCI in singleton pregnancies. STUDY
DESIGN: The total population of women (n=26,849) with singleton pregnancies delivered in Kuopio University Hospital during the study period between 2000 and 2011 was reviewed. Risk factors and the risk of adverse pregnancy outcomes (admission to a neonatal unit, fetal death, preterm delivery, low birth weight (LBW< 2500 g), the infant being small for its gestation age (SGA), low Apgar scores (<7) at 1 and 5 min and fetal venous pH<7.15) were evaluated separately among women with and without VCI by means of logistic regression analyses.
RESULTS: The incidence of VCI among women with singleton pregnancies was 2.4% (n=633 of 26,849). Independent risk factors for VCI were nulliparity, obesity, fertility problems, placenta previa and maternal smoking. VCI was associated with a 1.38-, 2.01-, 3.93- and 1.39-fold increased risk of admission to a neonatal unit, preterm delivery (<37 gestation weeks), LBW and SGA, respectively compared to pregnancies involving normal cord insertion. Of the women with VCI, 15.3% underwent non-elective cesarean section compared to 8.3% (p ≤ 0.001) of women without VCI.
CONCLUSIONS: The results suggest that the incidence of VCI increases along with an increase in fertility problems and maternal obesity. VCI is a moderate risk condition increasing the risks of prematurity and impaired fetal growth.