BACKGROUNDFew studies have given suggestions on appropriate individual progesterone dosage in patients with progesterone deficiency. This study was designed to provide a reference for the clinical use of oral progesterone by exploring the relationship among Body Mass Index (BMI), dosage of progesterone, and serum progesterone concentration. Many gynecology and obstetrics doctors are unfamiliar with progesterone treatment. Our study is intended to help determine the dosage of oral progesterone.

METHODSThis was a block randomized, open-label, prospective clinical trial. Eighty women undergoing cessation of menses were recruited, given oral progesterone therapy for 10 consecutive days. They were randomly assigned to four groups (four different doses of progesterone, n = 20): group A 100 mg/d, group B 200 mg/d, group C 300 mg/d, and group D 400 mg/d.

RESULTSSeventy-four patients (92.5%, 74/80) completed the study. It was observed that administration of progesterone significantly increased serum progesterone concentration in the four groups (all P < 0.001). And there is a positive correlation between the increase and dosage (r(p) = 0.613, P < 0.001). A further linear regression analysis found the major regression equation: when 18.5 kg/m(2) ≤ BMI < 24 kg/m(2), Y = 8.4820×10(0.003X) (R(2) = 0.425, P < 0.001); Y was the increase of serum progesterone concentration in nmol/L, and X was the dosage of oral progesterone in mg/d.

CONCLUSIONSSerum progesterone levels went up linearly as the dosage increased. The higher the patient's BMI, the higher dosage would be needed to achieve the same serum progesterone concentration. The appropriate dosage of oral progesterone for different patients can be roughly calculated in light of the results of this study.