Study Points To Importance of Checking IUD Position

April 19, 2011

Intrauterine devices (IUDs) can be a safe, effective, and relatively easy birth control option. However, pregnancy can occur if the IUD dislodges or is not placed properly. Dr Elysia Moschos, associate professor of obstetrics and gynecology, and Dr Diane M. Twickler, professor of radiology, at the University of Texas Southwestern Medical Center in Dallas, studied ultrasound findings, clinical symptoms, and outcomes for women with first-trimester pregnancies despite having intrauterine devices to better understand this issue.

Intrauterine devices (IUDs) can be a safe, effective, and relatively easy birth control option. However, pregnancy can occur if the IUD dislodges or is not placed properly. Dr Elysia Moschos, associate professor of obstetrics and gynecology, and Dr Diane M. Twickler, professor of radiology, at the University of Texas Southwestern Medical Center in Dallas, studied ultrasound findings, clinical symptoms, and outcomes for women with first-trimester pregnancies despite having intrauterine devices to better understand this issue.

The researchers conducted a retrospective review of 42 women who had IUDs placed and had positive serum human chorionic gonadotropin in the first trimester (Figure 1). All the women had previous successful pregnancies. Average age was 26 years; on average, the women had the IUDs in place for 2 years prior to the current pregnancy. Mean gestational age at pregnancy confirmation was 8 weeks.

Figure 1. Types of pregnancies found in women with IUDs (N = 42).


* resulted in spontaneous abortion

Only 36 of the women had their IUDs confirmed either by ultrasound or 2D imaging. In these women, the researchers found that 58% (21) of the IUDs were malpositioned. When specifically looking at intrauterine pregnancy, the researchers found the risk of intrauterine pregnancy (IUP) was 3 times as likely when the IUD was malpositioned or missing. Of the 31 patients with IUPs, 17 had malpositioned IUDs, 8 IUDs were found within the endometrium, and 6 were not seen (Figure 2).

Figure 2. Percent of malpositioned or missing IUDs in intrauterine pregnancies.

Moschos and Twickler found some common clinical indications, including bleeding, pain, and missing strings. However, not all women experienced symptoms; 11 women did not report any indication that would be suspect of a problem.

The researchers found term outcome information for 26 of the women; 20 had term deliveries and 6 had failed pregnancies within 20 weeks. Of the women who delivered at term, 10 had successful IUD removals. Five of the women had no identifiable IUDs; it was later determined that these were device expulsions.

“Gynecologists typically do a pelvic and speculum exam after placing an IUD, but there's no sonogram involved,” explained Moschos in a statement to the press. Even though the IUD displacement could have happened over time, she noted that initial verification by ultrasound would at least confirm initial positioning.

In discussing the clinical implications of the study, Moschos concluded, “Based on the results of our study, we believe that sonographic evaluation of IUDs after insertion and for surveillance should be a topic of ongoing consideration.”

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References

Moschos E, Twickler DM. Intrauterine devices in early pregnancy: findings on ultrasound and clinical outcomesAm J Obstet Gynecol. 2011; 204 [epub].

UT Southwestern Medical Center. Annual sonograms are needed to verify correct IUD position, obstetricians say. ScienceDaily. 2011; March 30.