Prolactin is a hormone that is secreted by the pituitary gland.  Prolactin is present in low levels in women who are not pregnant.  During pregnancy, a woman’s body ramps up the production of prolactin, sometimes as much as ten times the amount prior to pregnancy. 

Some women have a condition known as Hyperprolactinemia.  This refers to unusually high levels of prolactin in a woman who is not pregnant.  Hyperprolactinemia can create specific problems in regard to fertility.  It can cause a woman to produce an inadequate amount of progesterone during the luteal phase after ovulation. 

Hyperprolactinemia does not directly cause miscarriage.  However, Hyperprolactinemia may contribute to luteal phase defect.  The luteal phase is a part of the menstrual cycle.  It is the time between ovulation and the start of the next period.  Most of the time, the luteal phase lasts for between 10 and 14 days.  If your luteal phase lasts less than 10 or more than 14 days, it is referred to as a luteal phase defect.

If you conceive and you have a luteal phase defect, you may an early miscarriage.  This is because that a luteal phase defect cannot sustain a pregnancy because the uterine lining in these women begins to break down, bringing on the menstrual bleeding and causing an early miscarriage.

Prolactin and it’s relationship to miscarriage