Severe pain at interval IUD insertion: a case-control analysis of patient risk factors.

This investigation, using a case-control analysis approach on an IUD data set from a less-developed country center, delineated four risk factors in patient characteristics that are associated with severe pain at interval IUD insertion. They are: higher education (greater than or equal to seven years), low-parity (1-2 live births), longer open interval (greater than or equal to 13 months) between the end of the last pregnancy and insertion, and non-breastfeeding at the time of insertion. Adjusted relative risks estimated by odds ratios are 2.1, 2.7, 2.7 and 5.0, respectively. For women with a combination of the above risk factors, they have a further increased (additive in nature) risk of suffering severe insertion pain. Similar analysis was also performed on a developed country center data set for which only the effect of education and parity could be studied; an odds ratio of 5.0 for nulliparity was obtained. The plausibility of these findings as well as their clinical and programmatic implications are discussed.