Luteal Phase Defect
The span of time in a woman's menstrual cycle between ovulation and the occurrence of the next menstrual period is called the luteal phase, and for most women it lasts between 10-14 days. If this phase lasts fewer than 10 days or more than 14 days, a condition known as luteal phase defect may be present.
LPD, FSH and Pregnancy
This commonly misunderstood condition frequently affects fertility. Follicle stimulating hormone, or FSH, is created by the body during a normal menstrual cycle. FSH causes a mature follicle which holds an egg to be formed in one of the ovaries. The follicle bursts and becomes the corpus luteum from which is secreted progesterone. It is the hormone progesterone which causes the lining of the uterus to thicken, giving the fertilized egg a place to attach. If the luteal phase of the cycle is less than 10 days, there is not sufficient time for the lining to be prepared and a pregnancy cannot be sustained.
Information available from the InterNational Council on Infertility Information dissemination, Inc., (INCIID) in Arlington, Va., implies that women who use fertility charting - the monitoring of the basal body temperature of a daily basis - often notice that the elevated body temperature consistent with the luteal phase does not stay elevated for the average number of 12 days during the luteal phase. Also, women who monitor their ovulation time notice that their cycle begins sooner than the normal 12-14 day span.
The Progesterone Connection
If LPD is suspected, a serum progesterone test - a simple blood test - will be done about seven days after ovulation to measure the levels of progesterone in the body. If the results indicate a less than normal amount of progesterone production in the luteal phase, then an ultrasound is performed in order to view the lining of the uterus. This non-invasive procedure is normally done mid-cycle.
An endometrial biopsy is another diagnostic option and is usually done several days prior to the onset of the next menstrual cycle. A small sample of the uterine lining is taken and sampled to see if it is developed enough to sustain a pregnancy. The inspection is very detailed and the pathologist will be checking to see if the lining can be placed into a category as typical of a certain day in the cycle. If a discrepancy for more than a few days is discovered, then the lining is considered out of phase.
Depending upon whether ovulation-induction medications are used, a repeat biopsy during the treatment may be done to ensure the problem is corrected. The good news is that this condition is very responsive to treatment. However, the treatment is contingent upon finding the time in the phase the defect is occurring.