The Course of Minipuberty in Daughters of Women with Low Gestational Vitamin D Status

Abstract

Minipuberty is a term describing temporary, sex-specific activation of the hypothalamic–pituitary–gonadal axis, which is implicated in the development of male and female genital organs. Sons of women with low vitamin D during gestation were found to be characterized by increased activity of the reproductive axis and faster postnatal growth of genital organs. The current study assesses for the first time the course of minipuberty in female descendants of women with a vitamin D deficit. The study population included three matched groups of infant girls: children born to women with vitamin D deficiency (25OHD concentration below 50 nmol/L), offspring of women with vitamin D insufficiency (25OHD concentration between 50 and 75 nmol/L), and daughters of healthy females (25OHD concentration between 75 and 150 nmol/L). Salivary concentrations of estradiol, progesterone, 17-hydroxyprogesterone and androgens, as well as urine concentrations of FSH and LH, were assayed during the first 18 months of life (once a month in the first 6 months, bimonthly between months 6 and 12, and then every three months). At each visit, beyond hormone measurements, the investigators assessed the size of reproductive organs: ovaries, uterus and breasts. In daughters of mothers with vitamin D deficiency, concentrations of FSH, LH and estradiol were higher and detectable for a longer period of time, while ovarian volume, uterine length and breast diameter were greater than in the remaining groups. Children born to women with vitamin D insufficiency were characterized by higher FSH levels than daughters of healthy females, though the detection period was the same, and both groups differed in breast diameter. These findings suggest that low vitamin D status during gestation leads to more pronounced and longer-lasting activation of the reproductive axis, and is associated with increased dimensions of sexual organs, the magnitude of which depends on the degree of vitamin D deficit.