Reed SD, Armstrong MA, Getahun D, Gatz JL, Raine-Bennett TR, Alabaster AL, Ichikawa L, Saltus CW, Xie F, Zhou X, Fassett MJ, Peipert JF, Merchant M, Chiu VY, Hunter S, Schoendorf J, Shi JM, Chillemi GA, Im TM, Takhar HS, Asiimwe A, Anthony MS. Risk of uterine perforation and expulsion associated with breastfeeding among postpartum women with an intrauterine device insertion: results from APEX IUD. Poster presented at the Society of Family Planning Virtual 2020 Annual Meeting; October 9, 2020. [abstract] Contraception. 2020 Oct; 102(4):297.

OBJECTIVES: To evaluate risk of uterine perforation and intrauterine device (IUD) expulsion associated with breastfeeding among postpartum women.

METHODS: APEX IUD was a retrospective cohort study conducted at Kaiser Permanente (Northern California, Southern California, and Washington) and Regenstrief Institute (Indiana). The study included 94,817 women aged ≤50 years with an IUD inserted within 52 weeks postpartum and information on breastfeeding around time of insertion from clinical records, diagnosis codes, or questionnaires from well-baby visits in electronic health records. Perforation was defined as complete (IUD located in pelvis or abdomen) or partial (embedded in myometrium, as noted on imaging, hysteroscopy, or exam). Expulsion was defined as complete (IUD in the vagina, not visible in the uterus or abdomen with imaging, or patient-reported) or partial (any portion of the IUD located in the cervix or malpositioned on imaging or exam). We estimated incidence rates and adjusted hazard ratios (aHR), comparing breastfeeding to not breastfeeding, using propensity score adjustment for potential confounders.

RESULTS: For IUD insertions within 52 weeks postpartum, the incidence (95% confidence interval [CI]) of uterine perforation per 1,000 person-years of follow-up was 4.25 (3.89-4.62) in women who were breastfeeding and 2.50 (2.11-2.94) in those not breastfeeding. The aHR (95% CI) was 1.37 (1.12-1.66). The incidence (95% CI) of IUD expulsion was 10.23 (9.68-10.81) in breastfeeding women and 14.58 (13.62-15.59) in those not breastfeeding. The aHR (95% CI) was 0.71 (0.64-0.78).

CONCLUSIONS: Breastfeeding at the time of IUD insertion was associated with an increased risk of uterine perforation but a decreased risk for IUD expulsion.