Serum ferritin levels in pill and IUD users.

12 women using a low-dose combination oral contraceptive (OC) and 17 wearing a copper IUD were studied. Serum ferritin concentrations were measured before and 1, 3, and 6 months after commencing contraception. Ferritin levels in the iron-deficient range (below 50 mcg/l) were present in 5 (42%) and in 8 (47%) subjects, respectively, prior to the start of OCs or IUD insertion. The OC use induced only a temporary decrease in serum ferritin levels at the start of treatment, whereas 12 of 17 (71%) IUD users had reached iron-deficient levels by the end of the follow-up period. Thus, the use of OCs had no adverse effect on iron balance, but the monitoring of iron status and the administration of iron-replacement therapy seem to be indicated in the majority of women fitted with an IUD.