The luteal phase of your cycle is the time from ovulation until your menstrual period begins. The normal length of the luteal phase is 14 days, in a 28 day cycle. Women with a luteal phase defect have a much shorter phase, often ten days or less. If you manage to conceive, the much wanted pregnancy ends in miscarriage.
Low progesterone level is thought to be the cause of a luteal phase defect. There are a few causes of low progesterone. A low level of follicle stimulating hormone (FSH) can result in poor follicle development. This causes the body to not make enough progesterone. If the corpus luteum fails, the progesterone level will be low.
In some cases, the uterine lining doesn’t respond, even when the progesterone level is normal. As a result, the uterine lining doesn’t thicken as it should. If a fertilized egg implants, the lining may not be sufficient. This would cause an early miscarriage.
A blood test can be done to check the progesterone level. This test is usually done seven days after ovulation. If the level is low, the doctor should determine the cause of the luteal phase defect in order to correct the problem.
The doctor may do ultrasounds around the time of ovulation in your next cycle. This is done to check the follicle development. If the ultrasound shows the follicle development is not adequate, you may be prescribed fertility drugs to stimulate the follicles. If the follicles are developing normally, progesterone will be given to correct the low levels.
In some cases, an endometrial biopsy may be done to check the lining of the uterus. This is usually done a couple of days prior to the beginning of the menstrual cycle. The tissue is tested to determine the day in the cycle. If the date of the sample is more than two days different than the actual cycle, the cause is believed to be a luteal phase defect.
Once the defect is diagnosed and the cause is known, treatment can begin. You may be given fertility drugs in combination with progesterone to stimulate follicle development and ensure there is sufficient progesterone to support the pregnancy. You will be monitored by ultrasound, blood work, or both throughout the cycle and in the beginning of your pregnancy.
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