S. Diaz et al., Norplant (R) implants and progesterone vaginal rings do not affect maternal bone turnover and density during lactation and after weaning, HUM REPR, 14(10), 1999, pp. 2499-2505
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.