Frequency of non-hormonal contraception around conception and association with congenital malformations in offspring.

A case-control study using data on deliveries in the mid-1970s at five Connecticut hospitals (cases, n = 1427; controls, n = 3001) found little relationship between delivery of a malformed infant and use by the mother of nonhormonal contraceptive methods at conception. Of particular interest was the lack of an association with use of the rhythm method (odds ratio (OR) = 1.02, 95% confidence limits (CL) = 0.73, 1.42), spermicides (OR = 1.26, 95% CL = 0.85, 1.85) at conception and a modest association for the intrauterine device (IUD) one week before conception (OR = 1.99, 95% CL = 0.98, 4.04). Continued use of the IUD after conception may further increase the risk for malformations but this observation was statistically unreliable in the present study. Mothers of newborns with cleft lip and palate (OR = 2.91) and congenital hydrocele (OR = 4.64) were more frequent rhythm users at conception, and mothers of newborns with multiple anomalies had more recent IUD exposure (OR = 9.87), but these and all other specific congenital malformation groups were not significantly related to any non-hormonal contraceptive after adjustment for multiple observations. Potentially confounding maternal risk factors were controlled.