Expert Commentary

STOP relying on 2D ultrasound for IUD localization

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START using more accurate 3D ultrasound instead



Several decades ago, the negative publicity associated with the Dalkon Shield brand of intrauterine device (IUD) caused a decline in the use of this form of long-acting reversible contraception (LARC). However, there has been a resurgence in the use of IUDs in the past few years;1 the current opinion of the American College of Obstetricians and Gynecologists encourages first-line use of LARC, and the IUD is popular with patients.2

Related articles:
Let's increase our use of IUDs and improve contraceptive effectiveness in this country. Robert L. Barbieri, MD (Editorial; August 2012)
5 IUD myths dispelled. Anne A. Moore, DNP, APN (September 2-13)

Some patients with IUDs will experience more painful periods, intramenstrual cramps or bleeding, or heavier menses. Until recently, many clinicians (including us) believed these possible adverse effects were not unexpected and often warned patients that it was not abnormal if one or more of these occurred.

More recently, however, results of an important study showed that patients with part of their IUD not totally located within the endometrial cavity (eg, protruded into the cervix or partially piercing the myometrium) had an increased rate of pain and bleeding.3 Of patients with any abnormally located part of their IUD, 36% had abnormal bleeding and 39% had pain, compared with 15% of women who reported abnormal bleeding and 19% who reported pain when their IUD was totally positioned within the endometrial cavity (P = .02 and .03, respectively).

Related article: Malpositioned IUDs: When you should intervene (and when you should not). Kari Braaten, MD, MPH, and Alisa B. Goldberg, MD, MPH (August 2012)

A 3D ultrasound can reveal malpositioning not identified on 2D
Prior to the widespread availability of ultrasonography, some practitioners will remember placing a sound in the uterus taped to a tenaculum and obtaining a flat plate and cross table lateral abdominal x-ray to ensure an IUD was indeed “intrauterine.” With the advent of transvaginal ultrasonography, a long-axis view with a centrally located IUD was thought to definitively locate the device as intrauterine (FIGURES 1A, 2A, AND 3A).

Related articles:
How to identify and localize IUDs on ultrasound. Michelle Stalnaker, MD, and Andrew Kaunitz, MD (Images in GYN ultrasound; August 2014)
Update on Contraception. Melissa Chen, MD, MPH, and Mitchell Creinin, MD (August 2014)

Now, with the advent of 3D transvaginal ultrasonography and the ability to construct a coronal plane, some IUDs, which appear to be totally normal on 2D sonography, actually show an arm that pierces the myometrium or protrudes into the cervix (FIGURES 1B, 2B, AND 3B). This in fact is probably the location that must exist at insertion for so-called “migration” to occur through the myometrium as uterine contractions, especially with menses, occur.

So the next time a patient with an IUD reports pain or bleeding, STOP doing only 2D ultrasound and START obtaining a 3D coronal reconstructive view.

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