During 1988-1992, physicians used two study protocols to follow 612 women who had accepted the subdermal contraceptive implant Norplant at the Rabta Maternity Hospital of Tunisia. They used WHO criteria to select 375 women aged 18-40 (i.e., healthy women with no contraindications). The remaining 237 women and their infants underwent regular clinical and paraclinical examinations. 58 of these women had heart disease. 13 had diabetes mellitus. 11 women had hypertension. 22 women were breast feeding. The women's mean age was 30. They weighed on average 61 kg. Mean family size was three. 35% and 21% of the women used oral contraceptives or IUDs, respectively, before accepting Norplant. 57% experienced menstrual disturbances after accepting Norplant. 162 women (26.5%) asked for Norplant to be removed. Menstrual disturbances were the reason for removal among 37% of them. This rate was the same for both groups. 1.79% of the women conceived during Norplant use. None of these women had an ectopic pregnancy, however. None of the infants being breast fed had any problems with growth. Norplant appeared to have no adverse effects on lactation. Side effects occurred at the same rate in the healthy women as the women at risk. These findings show that women at risk tolerated Norplant well.