Pharmacokinetics of progesterone a few other countries under the brand name Progestasert. It was marketed between 1976 and 2001. The IUD was never widely used due to a relatively high contraceptive failure rate of 2.9% and the requirement of annual replacement. It contained 38 mg progesterone and released 65 μg progesterone into the uterus per day (adding up to about 35 mg after one year). For comparison, a woman's body produces on average about 25 mg progesterone per day during the luteal phase. While effective as a form of contraception and for decreasing menstrual bleeding and discomfort, long-lived IUDs can fundamentally only deliver
Menstrual cycle life, to be ovulated decades later, it has been suggested that this long lifetime may make the chromatin of eggs more vulnerable to division problems, breakage, and mutation than the chromatin of sperm, which are produced continuously during a man's reproductive life. However, despite this hypothesis, a similar paternal age effect has also been observed. As measured on women undergoing in vitro fertilization, a longer menstrual cycle length is associated with higher pregnancy and delivery rates, even after age adjustment. Delivery rates after IVF have been estimated to be almost doubled for women with a menstrual cycle length of more