It can cause the endometrium to not support a pregnancy
learn about Prolactin at http://www.conceivingconcepts.com/learning/articles/prolactin.html Hi...you will have a better picture on this issue with the below. 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. http://www.amazingpregnancy.com/pregnancy-articles/441.html
Luteal phase
Women have their luteal phase soon after ovulation is finished up to their first menstrual period. On average, women have a 14 days luteal phase. The normal luteal phase is 10-16 days. But if you want to get pregnant having 12 or higher luteal phase is ideal.
Menstral Cycle
The Luteal phase in which ovulation begins.
follicular phase, ovulation, luteal phase, menstruation
Development of the corpus luteum The corpus luteum develops from the ruptured follicle during the luteal phase after ovulation. -masteringbiology.com
From doing research it is possible to have LPD after a normal pregnancy, from reading nothing indicates that pregnancy itself will/would lead to this problem but I suggest doing some research maybe on FertilityFriend or one of the other fertility web sites to get more information. Basically having a normal pregnancy once does not necessarily mean you cannot have fertility issues later. Anything is possible. I had a Luteal Phase Deficiency for years which was the cause of my infertility. There are progrestrone supplements ie Duphaston, Crinone that can assist the phase however, they are prescribed by your doctor.
luteal phase
Progesterone
The four phases of the mentrual cyle are the follicular phase, ovulation, luteal phase, and mentruation
menstrual phase (menstruation)proliferative phaseischemic phasefollicular phaseovulatory phase (ovulation)luteal phase (also known as secretory phase)