Ahlgren M, Källén B, Rannevik G
Acta Obstet Gynecol Scand. 1976;55(4):371-5. doi: 10.3109/00016347609158516.
Of 159 pregnancies conceived after clomiphene therapy, 141 ended in childbirth, including seven sets of twins. There was a probable increase in the number of infants born with major malformations. These were exclusively to women who had not previously borne a normal infant. The incidence of malformed infants compares well with that published after gonadotropin therapy. The possibly higher incidence of malformations seen after drug-induced ovulation would therefore seem to be due to the underlying subfertility state and thus not a direct drug effect.