ULTRASONOGRAPHIC AND ENDOCRINE EVALUATION OF OVARIAN-FUNCTION AMONG NORPLANT(R) IMPLANTS USERS WITH REGULAR MENSES

With the objective of evaluating the ovulatory function among long-ter m Norplant implants users with regular menstrual cycles, we undertook this prospective study including 11 Norplant implants users and 11 con trol women who were not using hormonal methods of fertility control. E xposed and unexposed women had had at least three regular menstrual cy cles preceding enrollment. All women were followed during one menstrua l cycle by serial vaginal ultrasound and estradiol (E(2)), progesteron e (P), LH, and FSH measurements. Three Norplant implants users ovulate d, three had luteinization of an unruptured follicle (LUF), three had persistent follicle growth up to a mean of 33 mm without rupture, and two had no follicular development beyond 16 mm. Ten of the controls ha d normal ovulation and one had LUF. Mean peak LH and FSH among Norplan t implants users who ovulated were three- to four-fold lower than amon g controls. Although users of Norplant implants with regular cycles fr equently have luteal activity, the results of this study suggest that elevation of P during the second half of the cycle does not necessaril y indicate ovulation has occurred and may frequently be associated wit h the presence of luteinized unruptured follicle. When ovulation occur s, there are usually abnormal hormone levels (low LH/FSH peak, low pro gesterone) which may also contribute to the contraceptive effect of No rplant implants. (C) 1996 Elsevier Science Inc.