Obese women exhibit reduced serum progesterone levels on the day of embryo transfer in artificially prepared cycles involving administration of vaginal progesterone

José Bellver, Cristina Rodríguez-Varela, Pedro Brandão, Elena Labarta
Reproductive BioMedicine Online. Available online 1 June 2022. In press. 2022 doi:


Research Question: Is there any variation in serum progesterone concentration on the embryo transfer (ET) day regarding female body mass index (BMI)? Design: retrospective analysis including 3,210 infertile patients undergoing an ET in the context of an artificial endometrial preparation cycle with sequential administration of estrogens and micronized vaginal progesterone (MVP; 400mg/12h). Serum progesterone was measured on the ET day, 6±2 hours after last MVP administration. Serum progesterone levels were subdivided into optimal (≥9.2 ng/mL) or suboptimal ( <9.2 ng/mL), regarding the cut-off point defined according to our previous results. Primary objective was the correlation between progesterone levels on the ET day and patient BMI, as a continuous variable and according to four ranges (underweight: <18.5kg/m2; normal weight: 18.5–24.9kg/m2; overweight: 25–29.9kg/m2; obesity: ≥30kg/m2), following the WHO classification. Secondary objectives include the evaluation of reproductive outcome according to patient BMI and progesterone levels on the ET day. Results: Mean serum progesterone concentrations and the ratio of patients with progesterone levels above the cut-off point of 9.2ng/ml fell progressively as BMI increased. Overweight and obese patients had lower mean serum progesterone levels than under and normal weight women (p<0.001). There was a trend towards impaired reproductive results in obese patients with suboptimal progesterone concentrations, absent when concentrations were optimal. Conclusions: Serum progesterone concentrations on the ET day in artificial cycles with MPV decrease as BMI increases. Serum progesterone levels monitoring is highly recommended in order to ensure optimal concentrations and reproductive outcomes.