Breastfeeding and ovulation tests
One of the most common questions is why the ovulation test is always positive during breastfeeding.
This is due to changes made in hormones during breastfeeding, especially the increase of the hormone PROLACTIN.
Prolactin is a hormone responsible for lactation and its value increases postpartum.
Prolactin also has a local effect in the ovaries and prevents the growth of follicles. Thus at a concentration of >30μg, present at breastfeeding mothers, prolactin reduces the production of estrogen by theca cells of the ovary.
This results in the pituitary (a gland in the brain that regulates the cycle and secretes the hormones LH and FSH) tracing the low values of estrogens and secrete in turn higher levels of FSH and LH. Subsequently the increased LH and FSH act on the ovaries to increase the low estrogens.
This results in the base value of LH to be increased as happens in cases of polycystic ovary and the ovulation test to continuously detect this increased value (ie is continuously positive).
Nor should we forget that the test is positive over a certain value. If the base value of LH is increased, the test will be constantly positive.
Effect of breast-feeding on pituitary-ovarian function after childbirth
J. Bonner et al, British Medical Journal 11:4 (5988) : 82-84
Dr. BABATSIAS LAMBROS
SURGEON GYNECOLOGIST – OBSTETRICIAN
Retrained in London in Laparoscopy and Hysteroscopy (University dep. Of Obstetrics and Gynecology – Royal Free Hospital – London)
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