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This report compares the history of oral contraceptive (OC) use for 715 New York state women who gave birth to malformed infants with the history for a group of 715 matched controls who gave birth to normal children. The case mothers were found to have used the OC after last menstrual period (LMP), or just before conception, slightly more often than the controls. Confidence intervals for the relative risk estimates were wide, and were significantly higher than 1.0 only among the group of women whose children had one or more major structural or anatomical malformations. Cytogenetic abnormalities and hypospadias were not associated with OC use around or after the time of conception. For women who had children with major anatomical or structural malformations, the association with OCs was stronger among the older age group. The authors found no evidence of an increased risk among women who had conveived their child after one or more pill-free menstrual cycles. Several reported studies, including this one, show a predominance of males among malformed offspring whose mothers used OCs during pregnancy. These findings indicate that the association between birth defects and OC use around the time of conception is not large, but the association is not easily reconciled with a non-causal explanation.

The effect of oral contraceptive (OC) use was examined among parous breast cancer cases diagnosed at less than or equal to 45 years of age, and in two different general population control groups of parous women. The primary analysis compared 278 cases with 520 controls. In the secondary analysis, a subgroup of 190 cases were compared with 190 controls from another reference group. In both analyses, ever use of OC, duration of OC use, and OC use prior to first pregnancy showed no significant association with breast cancer risk. Also in both analyses, in women with prior benign breast disease OC use increased the risk of breast cancer, although this finding was statistically significant only in the larger group used in the primary analysis.

A random selection of 1,230 upstate New York childbearing women was used to examine the history of oral contraceptive use in women with a clinical diagnosis of benign breast disease. We found that 73 women who had benign breast disease had a reduced duration of pill use. When determining the reason for this reduction, we found that in a significant portion (P less than .05) of our benign breast disease cases, the women had been advised by their physicians to discontinue pill use for breast-related reasons. We then surveyed a large group of upstate New York physicians. One third of them considered benign breast disease a potential contraindication for starting oral contraceptive use. Nearly one half throught the development of benign breast disease to be a potential contraindication for continuing oral contraceptive use. It is premature to conclude that oral contraceptive usage protects against benign breast disease.

Investigation of the fertility-rate after discontinuation of use of oral contraceptives shows that the monthly rate consistently follows an oscillatory pattern. This pattern appears to be unique to women who have discontinued the use of oral contraceptives. It may result from synchronisation of a previously unrecognised natural cycle, rebound changes in the reproductive system following steroidal contraception, or an infertile period associated with early intrauterine mortality.

We examined the history of oral contraceptive usage in a group of 103 mothers of infants with Down's syndrome and an equal number of matched normal controls. We found no evidence of increased pill use among mothers of the abnormal infants either during the pregnancy or in the year before pregnancy.