Subdermal levonorgestrel implants and pituitary function.

This study was designed to report changes in circulating FSH, LH, and prolactin levels in women users of subdermal levonorgestrel implants. The subjects comprised 21 women implanted with 6 silastic rods, each containing 34 mg levonorgestrel, between days M0 and M+4 of the menstrual cycle. Blood samples were drawn prior to, 1 month and 6 months after implantation, during the early follicular phase in menstruating (n=12), and randomly in amenorrheic (n=9) subjects. No significant differences were noted between the mean values of estimated hormones at the 3 intervals of estimation in both regularly menstruating and amenorrheic groups.