IUDs (intrauterine devices) are an easy to use, effective, cost effective form of birth control, but they're not perfect. Pregnancy can occur with an IUD, even when it's being used properly.
Failure Rates
Both the progestin-releasing IUD and the copper IUD have low failure rates per year, approximately 1 percent or less. Progestin-releasing IUD pregnancy rates are slightly lower than copper IUDs.
Treatment
Women who become pregnant with an IUD in place should have it removed. If no string is felt protruding from the cervix, an ultrasound should be done to see if the IUD has fallen out.
Risks
Not removing an IUD increases the risk of infection, second-trimester miscarriage and preterm labor.
Complications
Women who become pregnant with an IUD in place have a higher rate of miscarriage. IUD failure also causes an increased risk of ectopic pregnancy (a pregnancy in the Fallopian tube).
Warning
Women with IUDs should always be aware of the possibility of failure. A missed period, unusually heavy period, fainting or pelvic pain should always be promptly investigated.
References
- "Clinical Gynecologic Endocrinology and Infertility"; Leon Speroff, Marc A. Fritz; 2005
- "Human Reproduction"; Risk factors for IUD failure; results of a large multicentre control-case study; Patrick Thonneau et al;2006
