The corpus luteum (CL) secretes prorenin, renin's inactive precursor. It may thus contribute to the renin-angiotensin-aldosterone-system (RAAS) activation that is required for maternal adaptation in pregnancy. Whether this activation is disturbed in pregnancies lacking a CL is unknown.To investigate maternal RAAS determinants in early pregnancy.Two observational prospective cohort studies.Two tertiary referral hospitals.Pregnancies (n=277) were stratified by CL number and in-vitro fertilization (IVF) protocol: 0 CL (programmed cycle frozen embryo transfer [FET], n=28), 1 CL (natural cycle FET, n=41 and spontaneous conceptions, n=139) and >1 CL (ovarian stimulation and fresh embryo transfer, n=69).Quantification of maternal prorenin, renin and aldosterone blood levels at 5, 9 and 11 weeks of gestation.Prorenin and renin were lower in the absence of a CL at all-time points when compared to 1 CL, while prorenin, renin and aldosterone were higher in the presence of >1 CL versus 1 CL (P<0.05). Ovarian stimulation with menopausal gonadotropin resulted in higher prorenin, renin and aldosterone concentrations during late first trimester than recombinant follicle-stimulating hormone (P<0.05). Prorenin, and to a lesser degree renin, correlated positively with serum progesterone and relaxin, but not serum estradiol. Total follicle diameter, BMI, PCOS and AMH were additional determinants of circulating prorenin. Finally, pregnancies conceived in the absence of a CL were more disposed to develop preeclampsia.CL number, IVF protocol, BMI, PCOS and AMH affect maternal RAAS activation in early pregnancy, and may thus contribute to pregnancy complications.