Effect of Immediate Postplacental Copper T380A Intrauterine Device Insertion Versus Postpartum Progesterone-only Pills on Uterine Niche Formation After Primary Cesarean Section: a Prospective, Open-label Randomized Controlled Trial

Eligible primigravida participants aged 18-45 years with a gestational age of ≥37 weeks undergoing a primary cesarean section for any indication were required to provide written informed consent, agree to attend follow-up visits for 6 months postpartum, and express a desire for postpartum contraception. After confirming eligibility and obtaining consent, a trained nurse selected an envelope for each patient and revealed the allocation to the patient and the operating obstetrician. Participants were randomized1:1 to either immediate postplacental insertion of copper T380A intrauterine device performed intraoperatively using the standardized intracesarean introducer-withdrawal technique or not to receive an intraoperative intrauterine device but they were instructed to initiate progesterone-only pills 4 weeks postpartum and at least 5 days before resuming sexual activity, till at least the end of 6th month postpartum. All lower-segment cesarean sections were performed by qualified obstetricians at Benha University Hospitals who were trained on the study protocol. The standard Kerr technique was used for the uterine incision, followed by double-layer continuous myometrial closure with braided polyglycolic acid 0-1 sutures, ensuring decidual sparing and visceral peritoneum closure. Follow-up visits were scheduled at 3 and 6 months postpartum.

• Ultrasound Assessment: Two independent, trained sonographers-blinded to each other's findings-perform transvaginal ultrasound examinations in both sagittal and coronal planes. At 3 and 6 months postpartum,intrauterine device displacement is considered if the distance between the dome of the uterine cavity to the upper part of the intrauterine device is > 3 mm and these participants will be provided with another method of contraception according to their wish and will be excluded from the final analysis . At 3 and 6 months postpartum, a niche is defined as an indentation ≥2 mm in the myometrium at the previous cesarean scar site. At 6 months postpartum uterine niche depth, length, width and residual myometrial thickness are to be recorded .
• Clinical Assessment: A separate obstetrician/gynecologist will collect data on menstrual patterns and breastfeeding initiation and continuation .