Anthony MS, et al. - In this investigation, researchers validated algorithms identifying uterine perforations and intrauterine device (IUD) expulsions and determined availability of breastfeeding status at the time of insertion of IUD. Participants in the study were 282,028 women ≤50 years of age with 325,582 IUD insertions. At 3 of the 4 research sites, algorithms with a high positive predictive value (PPV) for uterine perforation and IUD expulsion were developed. Breastfeeding status could be determined at all research sites at the time of the insertion of IUD. The findings suggest that a study can be successfully conducted retrospectively to assess the connections of breastfeeding and postpartum IUD insertions with the risk of uterine perforation and IUD expulsion. However, because of low PPV, automated application of algorithms must be supplemented with chart review for certain results at one research site.