Hormonal Factors.
Many fertility specialists fell that inadequate production of progesterone by a woman's corpus luteum can cause both infertility and miscarriage, especially recurrent miscarriage.However, this theory is not totally convincing.
First, gynecologic researchers have not been able to consistently identify undergrown endometrial lining tissue in women who supposedly habe inadequate corpus leuteum syndrome. This, after all, is one of the ways by which inadequatecorpus leuteum supposedly causes infertility and miscarriage.
Second, it has never been shown that giving progesterone to this group of women decreases their risk of miscarriage.
The issue of corpus luteum inadequacy as a cause of miscarriage remains one of great controversy among fertility experts.