Intrauterine device termination rates and the menstrual cycle day of insertion.

World-wide clinicians apparently prefer to insert the intrauterine device (IUD) during the bleeding phase of the menstrual cycle. To examine the benefits and risks of inserting IUDs at various times during the menstrual cycle, data on over 9000 women having copper T-200 IUD insertions were analyzed. During the first 2 months after IUD insertion: 1) rates of IUD expulsion are lower the later in the menstrual cycle ;he IUD is inserted; 2) rates of IUD removal for pain and bleeding and rates of accidental pregnancy, are higher the later in the menstrual cycle IUD is inserted, particularly after day 17. The present analysis suggests that the above are probably causal associations. It is estimated that 1000 insertions before day 11 will result in 9 more terminations of IUD use for expulsion, pain and bleeding, and accidental pregnancy than if the insertions are done after day 11. Furthermore, the copper T-200 IUD can be inserted with relative safety on the day it is requested if the woman's history indicates that she is unlikely to be pregnant. There is no justification for a blanket policy of inserting IUDs only during the menses.