The effectiveness of combined oral contraceptive pills (COCs) in preventing persistent corpus luteal cysts following oocyte retrieval: a randomized controlled trial

The objective was to compare the preventive effect of combined oral contraceptive pills (COCs) to the expectant management approach on the incident of corpus luteal cysts following oocyte retrieval in in vitro fertilization (IVF). A total of 130 IVF patients at the Infertility Unit of Siriraj Hospital were randomized into two groups following ovarian stimulation and oocyte retrieval. Participants in the study group received COCs containing 0.15 mg desogestrel and 0.02 mg ethinyl oestradiol per pill for 21 days (<i>n</i> = 65), while the comparison group underwent expectant management (<i>n</i> = 65). Transvaginal ultrasonography was performed to detect corpus luteal cysts (mean cyst diameter ≥ 10 mm) at 2 and 4 weeks after oocyte retrieval. Baseline characteristics were similar between groups. At 2 weeks, the incidence of persistent corpus luteal cysts was 58.4% in the COC group and 69.2% in the expectant management group (<i>p</i> = 0.2). A comparable, non-significant difference was also observed at 4 weeks (26.2% vs. 36.9%, <i>p</i> = 0.19). However, the mean cyst diameter at 4 weeks was significantly smaller in the COC group (5.74 mm vs. 9.39 mm, <i>p</i> < 0.01). The use of COCs does not effectively prevent the formation of corpus luteal cysts at 2 and 4 weeks after oocyte retrieval in the IVF process.