Expulsion of intrauterine devices was significantly more likely when the devices were inserted within the first 3 days after delivery compared with later insertions, based on data from more than 300,000 women.
Intrauterine devices are effective contraception, and current guidelines support immediate postpartum IUD insertion as a safe, effective, and convenient option, Mary Anne Armstrong, MA, of Kaiser Permanente Northern California, Oakland, and colleagues wrote. Although IUD expulsion rates are low overall, data from previous studies suggest that timing of insertion may affect expulsion rates, and that breastfeeding may play a role.
In the Association of Perforation and Expulsion of Intrauterine Devices (APEX-IUD) cohort study published in JAMA Network Open, the researchers reviewed data from the electronic health records at four sites; the study population included women aged 50 years and younger who underwent IUD insertion between 2001 and 2018.
The women were grouped by postpartum status and timing of IUD placement: 0-3 days, 4 days to 6 weeks, 6-14 weeks, 14-52 weeks, and nonpostpartum (defined as more than 52 weeks or no evidence of delivery).
The researchers also compared expulsion rates in postpartum women who were and were not breastfeeding at the time of IUD insertion based on clinical records, diagnostic codes, or questionnaires at well-baby visits.
The total study population included 326,658 women with a mean age of 32.0 years; 42% were non-Hispanic White, 17.2% were Hispanic other, 13.0% were Hispanic White, 11.9% were Asian or Pacific Islander, 8.7% were non-Hispanic Black, and 0.2% were Hispanic Black. Approximately 80% of the IUDs were levonorgestrel releasing.
A total of 8,943 expulsions were reported, for an overall expulsion rate of 13.94 per 1,000 person-years.
The adjusted hazard ratios for IUD expulsion were 5.34, 1.22, 1.06, and 1.43 for women with insertion times, respectively, of 0-3 days, 4 days to 6 or fewer weeks, 6-14 weeks, and 14-52 weeks. Women with nonpostpartum IUD insertion served as the referent.
The 5-year cumulative incidence of IUD expulsion was highest with placement between 0 and 3 days post partum and lowest with placement at 6-14 weeks postpartum (10.73% and 3.18%, respectively).
“Within the group with IUD insertions 0-3 days postpartum, the highest expulsion rates were discovered within 12 weeks of insertion, with the highest incidence rate occurring at week 6 (844 per 1,000 person-years), a time women are commonly seen post delivery,” the researchers noted.
In a subcohort of 94,817 women with known breastfeeding status, the 5-year cumulative incidence of expulsion was 3.49% for breastfeeding women and 4.57% for nonbreastfeeding women, with an adjusted HR of 0.71 for breastfeeding versus not breastfeeding.
“While women who accept immediate postpartum IUD placement report high satisfaction rates, information on women’s preferences and satisfaction associated with different timing of postpartum placement would also be helpful to understand the benefit-risk profile,” the researchers wrote in their discussion of the findings. “The fact that most expulsions in the immediate postpartum group occurred early presents an opportunity to mitigate risk of unrecognized expulsion and unintended pregnancy via counseling on signs of expulsion and follow-up examination.”
The study findings were limited by several factors including the potential misclassification of exposures and the primary outcome of expulsion, especially since some postpartum women may be lactating whether or not they are breastfeeding, the researchers noted. Other limitations included the combination of complete and partial expulsions, and the dating of IUD expulsion based on when it came to medical attention, which was not necessarily when it occurred. More data are needed on the potential association between lactational amenorrhea and lower expulsion risk among postpartum women who are breastfeeding.
However, the results were strengthened by the large and diverse study population, the use of linked mother-infant records to identify exposures, and the use electronic health records to identify outcomes, and the data can inform patient counseling for postpartum IUDs, the researchers concluded.