Uterine cavity length in postpartum women who are exclusively breastfeeding: is atrophy responsible for a higher perforation rate at Intrauterine Contraceptive Device (IUCD) insertion?

Women who are breastfeeding have a higher chance of experiencing a serious complication — called uterine perforation — when a doctor inserts an intrauterine device (IUD) for contraception. Researchers think this may happen because breastfeeding causes hormonal changes that shrink the uterus. This study compares the size of the uterine cavity in breastfeeding women, bottle-feeding women, and women who stopped breastfeeding at least two months ago, to find out whether a smaller uterus explains the higher perforation risk. You may be eligible if: - You have given birth at least once - You fall into one of these groups: (1) more than 6 months postpartum and not breastfeeding for at least 2 months; (2) 2–6 months postpartum and exclusively breastfeeding with no periods; or (3) 2–6 months postpartum and bottle-feeding from 6 weeks You may NOT be eligible if: - You have known uterine problems such as fibroids or an unusually shaped uterus - You have never given birth - You currently have an IUD in place - You are using hormonal contraception - You are pregnant Talk to your doctor about whether this trial might be right for you.