ASSOCIATION BETWEEN SEX HORMONES IN HUMAN BREAST MILK AND INFANT GROWTH AND DEVELOPMENT

Background– Although the influence of gonadotropins and steroid sex hormones on human growth and development are very well established, little is known concerning the role of these hormones in breast milk. Methods– In the present study, the concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol and progesterone in the blood and milk of 19 lactating mothers were measured by radioimmunoassay 1 and 6 months after delivery. Weight, height, head circumference and development of the infants were simultaneously clinically examined at 1 and 6 months. Results– Serum levels of LH, FSH and estradiol were 3–fold higher in the samples collected 6 months after delivery as compared to the first month, whereas progesterone levels were lower (55%) at six months than at one month. A positive correlation was found between the levels of all hormones in serum and in breast milk. The levels of FSH, LH and estradiol in the milk correlated directly with growth and developmental indices, whereas milk progesterone levels were negatively correlated with infant growth and development. Conclusion– The results suggest that the levels of FSH, LH and estradiol in human breast milk play an important role in the growth and development of infants. For progesterone, the opposite is true.