Sexual intercourse and vaginal absorption of progesterone (SexVAP): a cross-over randomized prospective pilot study

Does use of male condoms during sexual intercourse affect serum progesterone levels in women taking hormonal replacement therapy (HRT) with vaginal progesterone, compared with unprotected sexual intercourse and sexual abstinence as the reference for progesterone absorption?

A prospective, randomized, crossover pilot study was conducted (n = 40 couples). Eligible participants were infertile heterosexual couples. Women (aged 18-40 years; BMI <32 kg/m²) received oestradiol and vaginal micronized progesterone suppositories. Couples were excluded if men reported erectile or ejaculatory disorders. Upon initiation of progesterone, sexual abstinence was mandated, except for two planned intercourses as part of the study, one with and one without a condom. Progesterone serum levels were assessed three times: on day 2 of progesterone (during abstinence), on day 3 (10 h after the first planned sexual intercourse) and day 7 of progesterone (10 h after the second planned sexual intercourse).

Among the 40 couples included, 30 couples were suitable for per protocol analysis. On average, serum progesterone levels were 0.21 ng/ml (± 5.26) lower after an unprotected intercourse compared with sexual abstinence; serum progesterone levels were 1.52 ng/ml (± 5.09) higher after an intercourse with a condom compared with sexual abstinence. The linear mixed model showed no significant effect for condom use to affect the variation in progesterone levels (P = 0.08).

Sexual intercourse did not significantly affect serum progesterone levels during an HRT cycle using vaginal progesterone suppositories. Vaginal absorption of progesterone was similar regardless of whether a male condom was used.