GREGORY PINCUS 
The women were also questioned about changes in libido. 
About 80 per cent report no change, 5 per cent to 8 per cent 
an increase and 13 per cent to 18 per cent a decrease. The 
extent to which modesty governs these answers is, of course, 
imponderable, but certainly no drastic change is indicated. 
In recent years, several other ovulation-inhibiting steroids 
have been studied in similar field trials. These have been chiefly 
1g-norsteroids used in combination with an oestrogen. Among 
the objectives of research on other compounds is the discovery 
of substances effective in even lower doses than those now avail- 
able in order to provide a relatively inexpensive medication. 
However, in order to obtain adequate menstrual control, such 
compounds must be potent regulators of endometrial function 
as well as inhibitors of ovulation. 
We have in progress a study of a substance called ethynodiol 
diacetate (ED). Because of its good ovulation-inhibiting activity 
in test animals, we initiated our study in women with 2 mg. 
tablets of ED plus 0.1 mg. of the oestrogen we have used with 
all our progestins. In over 100 women who have used this 
medication for periods of up to 16 months, we observed the same 
general phenomena seen with Enovid: initially 16 per cent 
showing “‘reactions”’ and 6 per cent showing premature bleed- 
ing, both of which have become minimal by the fourth cycle of 
medication. Thus far in nearly 100 “‘exposure years’’, no con- 
ceptions have occurred among these women, probably because 
of their realization of the need for regularity in tablet taking. 
The “‘reactions”’ reported by these volunteers are occasional 
headache or dizziness, or nausea or vomiting. We have data 
indicating a large psychogenic element in their occurrence. 
Most of the subjects in these ED experiments were questioned 
prior to their entry into the project concerning the occurrence 
of such symptoms during their regular menstrual cycles. Of the 
122 patients responding to this questioning, 48 reported having 
had similar symptoms and 74 said that they had no such 
symptoms. More than half (58 per cent) of the women studied 
had such symptoms before medication but were “‘cured”’ during 
medication. On the other hand, 39 per cent of these women 
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