Blood pressure in normal pregnancies from Mexico city

Abstract

Objective: To determine the normal blood pressure (BP) in pregnancy, Mexico City. Methods: A cross-sectional observational study was carried out of BP on singleton normal pregnancies in Mexico City. Measurements followed a standardised methodology using automated electronic devices. Reference values of systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) were construc-ted. Maternal and gestation characteristics effects on BP were tested. The reference ranges of BP were adjusted for significant variables. Results: On 1,056 women of 33 years old mean age and 160.0 cm mean height, 1,915 measurements were made between 5 and 41 weeks of gestational age (GA) with 65.0 kg of mean weight. The median BP throughout pregnancy was 102.7/67.2 ± 9.3/7.4 SD mmHg, and 79.0 ± 7.4 SD mmHg the MAP. BP had a quadratic relationship with GA, being the lowest in 2nd trimester. SBP and DBP had a r = 0.71 linear correlation. Maternal weight had the most significant effect on SBP and MAP; height, on DBP. Maternal age, ethnic origin, parity, tobacco habit and family history had differential effects on BP. Gestation had no significant effect on SBP multivariate model. Conclusions: BP resulted lower than conventional standard for pregnant women. Diagnostic criteria for hypertension in pregnancy must be revised; reference values can be adjusted by maternal and gestation characteristics.