Norplant (R) implants and progesterone vaginal rings do not affect maternal bone turnover and density during lactation and after weaning

Bone density and turnover was assessed in a longitudinal study of healthy l actating women who initiated use of Norplant(R) implants (NOR, n = 29), pro gesterone vaginal rings (PVR, n = 28) or Copper T 380A intrauterine devices (T-Cu, n = 51, control group) around day 60 postpartum. Bone density, seru m calcium, phosphorus, alkaline phosphatases, parathyroid hormone (PTH), fo llicle stimulating hormone (FSH), oestradiol and prolactin, and urinary hyd roxyproline and creatinine were measured at postpartum months 1 (PM1), and 12 (PM12) and 6 or 12 months after weaning; at month 6 postpartum (PM6) ser um and urine tests alone were performed. Baseline characteristics and lacta tion performance were similar between groups. Biochemical markers of bone t urnover were higher at PM1, PM6 and PM12 than after weaning, with no differ ences between groups. Bone density in the lumbar spine (L2-L4) and femoral neck at PM1 and PM12 (similar to 1.11 g/cm(2)) was similar in three groups. Lumbar spine values were found to be lower in lactating women than those p resent in nonlactating women, but increased after weaning to similar values , The two progestin-only contraceptives studied appear to have no deleterio us effect upon bone density and metabolism in healthy lactating women.