Abstract
Minipuberty (MP) consists of a postnatal activation of the hypothalamic-pituitary-gonadal (HPG) axis, which occurs physiologically during the first months of life. In preterm infants, MP might lead to stronger hormonal stimulation, but specific literature is still scarce. We present the case of a pair of monochorionic diamniotic twin girls, born at 31 weeks of gestation and adequate for gestational age (AGA). At one month old, one of the twins presented with severe edema in the vulva and swelling of the major and minor labia. Laboratory evaluations highlighted increased LH, FSH and estradiol serum concentration. Pelvic ultrasonography and MRI showed a pubertal pattern. Brain imaging was unremarkable. During the one-year follow-up, a decreasing trend of hormonal levels was detected, together with the spontaneous regression of clinical and sonographic pubertal signs. The same hormonal workup was also performed on the other twin, who displayed mildly elevated gonadotropins and estradiol, without evidence of pubertal clinical signs. This case suggests that the amplitude of postnatal HPG activation might be exacerbated in preterm infants, with evidence of puberty changes in clinical, laboratory and sonography data. The spontaneous resolution, together with the exclusion of other causes of precocious puberty, is suggestive for MP of infancy.