hb1

Hi Lol78, I did loads of searches on google, there were a lot relating to hormonal imblances. I am new to this site so I can't post the links but here is an exert from a piece on women's health but there are a lot of other sites that have similar info.

Miscarriage And Insulin Resistance

The miscarriage rate among PCOS pregnancies is between 45 and 50 percent as compared to the national average of 15 to 25 percent in the general population. It can very difficult to diagnose the exact cause of the miscarriage and many such events go unexplained, although those women with PCOS caused by insulin resistance have a higher risk than those without the condition. The effect of high levels of insulin may cause increased blood clotting in the uterus which, in turn, leads to insufficiency of the placenta. The failure of the placenta to properly nourish the baby and remove toxic waste from the environment results in miscarriage.

Possible Causes Beyond Insulin Resistance

Insulin resistance is not the only hormonal link between PCOS and miscarriage. Some studies have found links between miscarriage and high levels of Luteinizing Hormone (LH). LH is a glycoprotein hormone that stimulates ovulation and some women with PCOS have a higher level of LH during the first half of their cycle. This signals the egg to prematurely disconnect from the supporting cells and the egg then stops maturing. This interruption in the maturation process of the egg may result in abnormal chromosomes which, in turn, increase the probability of miscarriage.

Research completed at the Virginia Commonwealth University Medical Center discovered that pregnant women with PCOS lacked high enough concentrations of two vital proteins that are found in the uterine lining: glycodelin and IGF binding protein. Both of these proteins may play a significant role in the implantation of the embryo in the uterus since their secretion occurs during pregnancy and affects the endometrium.

hb1

This is an exert I found about luteal phase defect:

Luteal phase defect. The luteal phase is the second half of your menstrual cycle, the time between ovulation and onset of the next menses. A luteal phase defect is essentially a failure of the uterine lining to be in the right phase of development at the right time, thus preventing implantation of the fertilized egg, or making the embryo's attachment to the uterus precarious.

A luteal phase defect may occur at several points during a menstrual cycle. It's thought that most luteal phase defects originate in the follicular phase of your cycle, before ovulation.

During the follicular phase, your body may not produce enough FSH (follicle stimulating hormone), or your ovaries have a weak response to FSH. The consequence is inadequate follicle development. After the follicle releases its egg, it converts itself into a different structure called the corpus luteum.

The corpus luteum produces the progesterone needed to thicken the lining of your uterus and stimulate development of additional blood vessels, which provide a place for your embryo to attach and to grow.

However, poor follicle formation will lead to a poor quality corpus luteum, and thus the corpus luteum is less likely to secrete the amount of progesterone required to ensure that the uterus can support the development of your embryo.

A luteal phase defect may also be caused by excessive levels of LH (luteinizing hormone) too early in the menstrual cycle, or an improperly timed LH surge.


also:

The only situation where progesterone is a sure solution is with a luteal phase defect, where the corpus luteum, which is formed along with egg at ovulation, does not produce the hormones needed to sustain a pregnancy. For most women, however, this is usually not an every-month problem. Usually the situation rights itself with the next egg and the next corpus luteum. This problem, if it is a permanent one, can be diagnosed through two separate endometrial biopsies. Progesterone must be started 48 hours after ovulation to work. By the time you have missed a period, it is too late to save a pregnancy with a luteal phase defect.

hb1

women with pcos are also likely to have low progesterone which can cause miscarriage - there is plenty of info when searching this on google.