Introduction:

Population-specific reference ranges for uterine artery (UtA) mean pulsatility index (PI) throughout pregnancy have been shown to be of value in antenatal care.

Objective:

To construct reference values for UtA mean PI throughout pregnancy, customized by maternal characteristics, transvaginal measurement and blood pressure in a Mexican population.

Methods:

Cross-sectional study in 2286 normal singleton pregnancies in Mexico City. Blood pressure and UtA mean PI were measured using standardized methodology. Reference ranges by gestation were constructed. The effects of independent variables were tested by multiple linear regression.

Results:

UtA mean PI median value between 11 and 41 weeks decreased from 1.714 to 0.523. The 95th percentile decreased from 2.600 to 0.653. Previous parity without preeclampsia had the main effect on UtA mean PI. Mean blood pressure had an effect on UtA mean PI by interaction with parity. Previous preeclampsia had an effect on UtA mean PI by interaction with maternal characteristics. A correction factor was obtained for transvaginal measurement.

Conclusions:

UtA mean PI usually decreases according to placentation and maternal adaptation to pregnancy. The effects of parity on blood pressure and UtA mean PI might reflect cardiovascular remodeling after gestation.