DISCUSSION 
among some 5,000 women taking this drug we have yet to see a 
single case of invasive carcinoma of the cervix. 
Hoagland: What about cancer of the breast? 
Pincus: ‘The women have not been of the susceptible age. 
Koprowski: Women who are now taking oral contraceptives 
on a continuous basis are 20—40 years of age and their suscepti- 
bility to gynaecological cancer can be determined in 20-30 
years’ time. Only then will it be possible to assess fully the 
safety of oral contraceptives currently employed. If, by a stroke 
of ill luck, it should turn out that the use of oral contraceptives 
has an adverse effect on the incidence of malignancy, equally 
effective substitutes should be developed and be available, 
since, by then, an abrupt stop in the massive use of contracep- 
tives may have an equally disastrous effect, although of a 
different type, on the population. 
Klein: Do either the progestins or the other compounds 
cause malformations? Is there an effect either on the immediate 
pregnancy or on subsequent pregnancies even in laboratory 
animals? And have you ever seen malformations in the babies 
of women who have been taking these compounds? 
Pincus: All the compounds that I showed you, except those 
used in the very latest studies on implantation inhibition, have 
been administered experimentally to animals and their effects 
on the embryo have been studied. Several of them tend to 
cause masculinization of the embryo. The particular prepara- 
tion that we have worked with, Enovid, is probably not a 
masculinizing substance. In our studies in the Caribbean 
roughly 300 women have used the material at least up to the 
time they have decided to have another child and among these 
children there has not been a single abnormality, particularly 
in relation to sexual development. However, Dr. Wilkins of 
Johns Hopkins thinks that the use of one of these compounds, 
17—ethinyl-19-nortestosterone (ethisterone), should definitely 
be avoided early in pregnancy, since he has seen a number of 
cases of pseudohermaphroditism (slightly virilized girls). Much 
more work will be done on this in the future but the experi- 
mental work with animals so far indicates that the ovulation- 
IIo 
