Infants with single umbilical artery studied in a national registry. 3: A case control study of risk factors.

This case control study reports associations between single umbilical artery (SUA) in newborns and some maternal biological characteristics. The study is based on chromosomally normal singleton infants born in Sweden between 1983 and 1990. Information on the maternal characteristics studied was obtained prospectively. There were 2920 cases identified and 5840 controls were selected. An association was found with: previous perinatal death, retained placenta, placenta praevia, maternal diabetes, epilepsy and hydramnios. Increased odds ratios were seen also for spontaneous abortion and abruptio placentae but did not reach statistical significance. No association was found with previous induced abortion, involuntary childlessness, or the use of contraceptives after the last menstrual period.