In a reproductive‑age woman with a bicornuate uterus, can an intrauterine device be placed safely and what are the recommended evaluation and placement techniques?

IUD Placement in Bicornuate Uterus

IUD placement in a bicornuate uterus is contraindicated and should not be performed, as a known uterine cavity anomaly is a specific contraindication to IUD insertion. 1

Why IUDs Are Contraindicated

• Known uterine cavity anomalies, including bicornuate uterus, are listed as contraindications to IUD placement in the Society for Maternal-Fetal Medicine guidelines, which recommend delayed insertion when such anomalies are present. 1

• The bicornuate uterus has two separate uterine cavities that are only partially fused, creating an abnormal cavity shape that prevents proper IUD positioning and increases the risk of expulsion, malposition, and perforation. 1

Diagnostic Confirmation Before Any IUD Consideration

If there is uncertainty about the diagnosis of bicornuate uterus, proper imaging must be performed:

• MRI is the gold standard for diagnosing bicornuate uterus with 100% accuracy, compared to 92% for 2-D transvaginal ultrasound. 1

• A fundal cleft >1 cm on either transvaginal ultrasound or MRI confirms bicornuate uterus and differentiates it from septate uterus (which has a fundal cleft <1 cm). 1

• 3-D ultrasound with sonohysterography has 100% accuracy in classifying bicornuate uteri and is an alternative to MRI when available. 1

Alternative Contraceptive Options

Since IUD placement is contraindicated, counsel the patient about alternative highly effective contraceptive methods:

• Contraceptive implants (etonogestrel) are appropriate alternatives as they are not affected by uterine anatomy and have similar efficacy to IUDs. 1

• Other options include combined hormonal contraceptives, progestin-only pills, depot medroxyprogesterone acetate injections, or barrier methods depending on the patient's medical history and preferences. 1

Critical Clinical Pitfall

• Do not attempt IUD placement simply because the device might fit into one horn of the bicornuate uterus. The abnormal cavity geometry prevents proper fundal positioning, which is essential for IUD efficacy and safety. High fundal placement decreases expulsion rates in normal uteri, but this cannot be reliably achieved in bicornuate anatomy. 1

• If an IUD is inadvertently placed in a patient later discovered to have a bicornuate uterus, perform ultrasound to assess position and strongly consider removal with transition to an appropriate alternative method. 2, 3