(Loss of Periods after Birth Control Pills)
Written by Dr.M.D.Mazumdar, MD
Post pill amenorrhea is described as the loss of menstrual periods for at least 6 months after stopping birth control pills. The incidence of post-pill amenorrhea ranges from 0.2% to 3%.
Cause of Post-pill Amenorrhea
Post-pill amenorrhea is believed to be due to suppression of the pituitary gland by the birth control pills.
In a normal menstrual cycle, the pituitary gland produces hormones like Follicle Stimulating hormone (FSH) and Leutinizing Hormone(LH). These hormones stimulate the follicles in the ovary to develop.
The enlarging follicles produce estrogen as they grow and develop into maturity. Progesterone is produced after the follicle ruptures (called 'ovulation') at around the 14th day of the menstrual cycle. Estrogen and progesterone together cause the endometrium (inner uterine lining) to grow. A menstrual period is caused when this endometrium sheds at the end of the menstrual cycle.
All birth control pills contain the hormones, estrogen and progesterone.
When a woman takes these pills, the blood level of these hormones increases.
The high level sends a negative feedback to the pituitary gland indicating that there is sufficient estrogen and progesterone in the body. As a result the pituitary gland stops producing FSH and LH.
Ovulation does not occur without FSH and LH and pregnancy is prevented.
When a woman takes birth control pills for a sufficient length of time, the negative feedback to the pituitary gland may persist even after the pills are stopped.
This prevents ovulation and resumption of menstrual periods.
Sometimes post pill amenorrhea may be characterized by irregular and scanty periods rather than by complete stoppage of periods. But the cause is the same.
Diagnosis of Post-pill Amenorrhea
The diagnosis of post-pill amenorrhea is usually made when there is loss of periods after a prolonged history of taking birth control pills.
Ultrasonography will reveal ovaries with no signs of developing follicles and ovulation even after having stopped the pills for 6 months.
Blood tests showing a low level of FSH, LH and estrogen is usually sufficient to confirm the diagnosis.
Treatment of Post-pill Amenorrhea
The first line of treatment in case of post-pill amenorrhea is waiting for a spontaneous remission of the amenorrhea and a spontaneous occurance of periods.
The time limit is usually six months. But if the woman is anxious to get her periods, active treatment may be started after waiting for only three months.
The standard treatment of post-pill amenorrhea is by stimulating the pituitary to produce FSH and LH. This is done by the drug clomiphene citrate.
Clomiphene citrate is a drug which can block the estrogen receptors in the uterus and other reproductive organs. This sends a signal to the pituitary that there is no estrogen in the body.
The pituitary then starts to produce more and more FSH to cause growth of follicles in the ovaries. The enlarging folllicles produce estrogen which stimulates the inner lining of the uterus (endometrium) to grow. Shedding of this endometrium causes menstruation or periods.
Clomiphene needs to be taken for 3 months for regular periods to resume.
Although, progesterone is often prescribed in postpill amenorrhea, it is not effective in stimulating the development of follicles in the ovaries. Without follicular growth, ovulation does not occur and without ovulation, it is difficult to get regular periods, although anovular periods can occur from time to time.
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