I agree with PTree - I would recommend using natural progesterone cream. There are books/articles by Dr.John Lee discribing how estrogen dominance/progesterone deficit has many consequences including infertility and carrying a baby to terms - here is one excerpt I found for you doing a quick search:
Progesterone is the progestation hormone. It keeps the bloody lining intact as a rich natural health food restaurant open 24 hours a day for the fertilized egg when it lands there and begins to multiply. This very tiny living being has to have a constant food supply, and as there is yet no placenta or umbilical cord to supply nutrients, the bloody lining is the baby's first food supply. Also the baby always has a different DNA than the mother, and the body's natural defense system always tries to reject nonself. The only thing known to biology that is capable of turning off this defense system in relation to the baby's different DNA is progesterone. Without progesterone the bloody lining is shed and the pregnancy is terminated. Many women who have experienced multiple miscarriages find that they can carry their babies to term by using natural progesterone. Dr. Lee has received hundreds of phone calls and letters telling him that they are so grateful to finally have a baby that they have named their baby after him when it was a boy.