Endocrine causes
-------------
Thyroid disorders

Although there is no firm evidence that thyroid disorders are associated with recurrent miscarriage, historically women with underactive thyroid (hypothyroid) have been seen to be at grater risk. Any research studies have tried to prove a definit link, but so far without success. However, so strong is the association in many people’s minds that often a small dose of synthetic thyroid (in itself not harmful to pregnancy) is sometimes given to a recurrent miscarrier in the hope that it might be of some help. At present, however, neither underactive nor overactive (hyperactive) thyroid has been conclusively proved as a cause of miscarriage. You might have a blood sample taken, nevertheless, which would be sent to the laboratory to test for thyroid disorders.

Luteal phase defect (LPD)

If you experience pain at the time of ovulation (called the mittelschmerz), that means your are ovulating (producing an egg), and in effect you are also foriming the corpus luteum. The pain is usually felt on one or both sodes, low down in the abdomen. It lasts a few hours and cramplike in nature. The pain may be accompanied by a sticky discharge that can even be blood-tinged. This is called an ovulation cascade.one signal of the corpus-luteum defect would be the lack of a rise in temperature during your normoal menstrual cycle. Normally, if you ovulate well, you temperature would be raised for at least ten days following ovulation. The progesterone produced by the corpus luteum causes a temperature rise (the thermal shift) that should last 10 to 14 days if your production of that hormone is normal.