Interestingly, the word progesterone is given its name because of its vital supportive role in gestation (Latin: gestare), a fact that sheds some insight into its importance in the reproductive process.
Modern science confirms that insight, as, of all female hormones, progesterone is the one most essential for conception and to the survival of the fertilized egg and the fetus throughout gestation.
At ovulation, progesterone levels rapidly rise from 2-3 mg/day to an average of 22-25 mg. per day, peaking as high as 30 mg/day. If fertilization does not occur in ten or twelve days, progesterone levels fall dramatically, triggering the shedding of the secretory endometrium (the menstrual cycle).
If pregnancy does occur
Progesterone production is taken over by the placenta which secretes an ever increasing supply, reaching 300-400 mg/day during the third trimester!
Among the numerous other desirable effects of Natural Progesterone are the following:
Because progesterone is essential to prevent the premature shedding of the supportive secretory endometrium, a significant drop in progesterone levels or blockade of progesterone receptor sites during the first 10 – 12 weeks of pregnancy will likely result in the loss of the embryo (miscarriage).
Dr. Katherine Dalton reports (anecdotallly) that women who use a properly formulated progesterone cream during the first 19-20 weeks of pregnancy produce healthier, more intelligent children.