Effect of ovulation induction on uterine blood flow and oestradiol and progesterone concentrations in early pregnancy

To determine if oestradiol and progesterone concentrations arerelated to uterine blood flow in early pregnancy, we measuredthese hormones at the time of vaginal Doppler ultrasound beforeand after the beginning of intervillous circulation in spontaneouspregnancy (group I), after clomiphene citrate administration(group II), and after clomiphene citrate plus human menopausalgonadotrophin (HMG) administration (group III). Despite largeincreases of oestradiol concentration in groups II (60%) andIII (300%) and of progesterone in groups II (100%) and III (300%),compared with group I, increases in blood flow were modest duringthe first 9 weeks of gestation. Uterine artery flow volume increasedby 20% in group II and 33% in group III (P 0.02); average velocityincreased by 37% in group III (P < 0.003) compared with groupsI and II; vessel diameter increased by 15% in groups II (P <0.025) and III (P < 0.001) compared with group I; and theuterine artery resistance index decreased by 3 to 5% in groupHI (P = 0.004) compared with groups I and II. Serum oestradioland progesterone concentrations were unrelated to the uterineartery resistance index or volume by an analysis of covariance.We conclude that uterine artery blood flow is significantlyincreased during early pregnancyfollowing HMG administration,and that the increase is unrelated to increases in oestradioland progesterone concentrations.