What happens if I take too much progesterone?

Progesterone is an essential hormone for successful implantation.

It has been shown that there are levels of progesterone in the blood (below 10-10.6ng/mL) at which, without ‘overdosing’ (adding subcutaneous progesterone to vaginal progesterone), the chances of pregnancy and live birth decrease by up to 30%. The addition of subcutaneous progesterone (progesterone shots) was successful in normalising progesterone levels (above 10ng/mL) in 28% of cases.

These studies show that if progesterone levels are below this threshold the day before or the day of transfer, the chances of pregnancy decrease. And, if we perform this ‘overdosing’ with subcutaneous progesterone, the chances of pregnancy are equal to those of patients with optimal progesterone levels on the day of the test.

Furthermore, during the course of these studies, progesterone overdosage has been shown to have no deleterious effects on the likelihood of pregnancy and no potential adverse effects on the unborn child. The side effects of progesterone are limited to nausea, constipation and increased sleepiness.