This study aims to evaluate the uptake of oxytocin following intravaginal administration of Vagitocin 400IU over a period of 15 days and also to compare oxytocin bioavailability after vaginal and intravenous administration. 12 healthy postmenopausal female volunteers, 40 to 70 years old with vaginal atrophy will be included and will self-administer Vagitocin intravaginally on day 2-14 (day 1 and 15 Vagitocin is given in the clinic). On day 22 a single intravenous dose of oxytocin 10 IU Syntocinon® will be given. Oxytocin plasma levels after intravaginal and intravenous administration will be analysed day 1, 15 and 22 at timepoints: -1.0, -0.5, 0, 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0 and 8.0 hours, relative to dosing. Based on the obtained plasma levels for oxytocin, pharmakokinetic variables will be calculated. The % of oxytocin which was absorbed following vaginal administration (bioavailability)will also be calculated.