Outcome of pregnancy after clomiphene therapy

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. The outcome of 159 pregnancies conceived after clomiphene therapy was investigated. An extrauterine pregnancy, a hydatidiform mole, and 16 miscarriges followed, representing an 11.2% pregnancy loss before the 28th week. There were 141 childbirths; 7 were twin births. Of the 148 infants, 8 had major malformations (5.4%). The number of expected malformations at the usual 3.2% rate was 4-5. The 3 cases of club foot were unusual as the usual rate is 1 in 1000 births. There were 119 normal infants and 6 with slight abnormalities. Birth weights were normal. Of the 8 infants with malformations 7 were born to women who had a previous child with preluxation of the hip. The incidence of malformed infants was similar to that recorded after gonadotropin therapy. It is concluded that the increased incidence of malformations may have been due to the existing subfertility which made the clomiphene therapy necessary. An amniocentesis, with alpha-fetoprotein determination and cytogenic analysis, in such cases might determine the presence of some of these malformations.