Ovulation rates after oral administration of the 1.5-mg levonorgestrel emergency contraception regimen among normal-weight and obese women

Effect of levonorgestrel emergency contraception on implantation and fertility: A review

“…We identified 9 studies that reported rates of inhibited ovulation after Levonorgestrel EC intake before or at the LH surge [19][20][21][22][23][24][25][26][27]. Among studies reporting on the efficacy of Levonorgestrel EC in relation to the timing of ovulation, 5 were placebo-controlled (or equivalent) and of moderate to high-quality evidence [ 19 −22 , 24 ].…”

“…Another in vivo study showed that vaginal Levonorgestrel EC exposure after the LH surge had no effect on 14 endometrial receptivity markers, but that oral exposure affected the expression of three biomarkers: a reduction in expression of progesterone receptors (PR-A and PR-B) in the glandular epithelium, (21), serum hormone measurements (28), or repeated data from previous cycles (27).C = Assessed as low-quality evidence. No control group, small or moderate sample size, timing of ovulation verified by ultrasound and/or serum-hormone measurement (22,24,26) or menstrual cycle length (25).…”