Lactating without pregnancy

Dr Sagarika Agarwal
What is hyperprolactinemia?
Some women face pregnancy like symptoms – loss of menstrual cycles, production of milk and loss of libido. This is attributable to a condition called hyperprolactinemia, where the level of prolactin hormone is more than normal levels in the blood. High levels interfere with estrogen production and cause changes in ovulatory cycles leading to irregular menstrual periods.
The primary function of prolactin is to enhance breast development during pregnancy and to induce lactation.  Though small amounts of this hormone circulate in the blood, even though a woman is not pregnant, the amounts increase during pregnancy and after birth. More than 75% of the women in this condition produce milk without being pregnant.
Though very rare, with high levels of prolactin in men can lead to loss of libido, impotency, erectile dysfunction, and even galactorrhea. Decreased levels of testosterone are an after effect of this condition.  If the condition is untreated the quality and motility of the sperm reduces and even the production of sperm becomes defective.
It is more popular in female with child bearing age, even though the relevant conditions remain normal. Women with good ovarian reserve can also have irregular periods highlighting the advent of the disorder.
High prolactin levels causing infertility
High prolactin levels in the blood affects reproduction by either disinhibition (e.g., compression of the pituitary stalk or reduced dopamine levels) or excess production from a prolactinoma (a type of pituitary adenoma) which   inhibits the secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus .This decrease in level of  gonadotropin-releasing hormone (GnRH)  in turn decrease the secretion of luteinizing hormone (LH) and Follicle stimulating Hormone (FSH) leading to infertility.
Once the levels of prolactin are elevated, women have a decrease in menstruation and have anovulatory infertility due to deficiency of estrogen levels in the blood. In some cases changes in menstrual flow is marked along with amenorrhoea. Even on not being pregnant or with any history, breast produces milk with pain due to tissue changes occurring in the breast with increased levels of prolactin and loss of libido also causing vaginal dryness.
Unlike women, due to lack of any reliable indicator like menstruation, it is difficult to identify the exact cause in men. They may have gradual loss of libido, erectile dysfunction, infertility and even enlarged breast .These factors are missed many times and the underlying cause is not identified.
Related consequences in female
As the estrogen production from ovaries is affected in this condition, apart from leading to infertility, estrogen deficiency causes reduction in bone mineral density (BMD) and increases the risk of osteoporosis. Estrogen also plays a vital role in protecting the heart from any ailments, and its imbalance can lead to heart disease later in life. Excess prolactin production due to pituitary tumor may lead to headaches, vision disturbances and reduce the production of other hormones causing hypothyroidism which is another factor causing infertility.
How to diagnose?
Medical history of unexplained milk secretion (galactorrhea) or irregular menses or infertility and in men with impaired sexual function and milk secretion is very important for diagnosis of this condition. If the history suggests hyperprolactinemia, as a first step blood test to check serum prolactin levels is done preferably fasting sample and if the levels are high further assisting tests may be required. Usually, pregnancy tests (in case of amenorrhea) and tests for checking levels of thyroid hormone levels are done to rule out hypothyroidism.
In case if the prolactin levels are very high, a tumor may be suspected and in that case, MRI of the brain and pituitary glands is advised that uses high frequency radio waves to obtain images of the tissues and the size of tumor.
Is it treatable?
The first step of the treatment is to identify the underlying cause of the condition which may be either physiologic, use of certain medications, a thyroid or hypothalamic disorder or pituitary tumor or some systemic disease. Once the root cause is identified which is essential to rule out any tumor, medicines which are dopamine agonists can be given to decrease the prolactin levels. This re-establishes the FSH, LH and estrogen levels thereby restoring fertility and regular and normal ovulation.
(The author is  IVF Consultant, Indira IVF Centre, New Delhi )


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