Early prediction of antepartum hypertension

We validated a mid-pregnancy screening mean arterial pressure (MAP2) of 85 mmHg or higher as a significant predictor of hypertension in pregnancy. During the 17-month period from October 1984 through February 1986, 730 women, or 16% of all women cared for and delivered at our institution, were screened at or near 20 weeks of amenorrhea. Of the 139 women with a MAP2 of 85 mmHg or higher, 21.6% developed antepartum hypertension, compared with only 0.7% of the 591 women with a MAP2 below 85 mmHg. The screening MAP2 level of 85 mmHg was the optimal cutoff for MAP2 as a screening test. Controlling for the value of the screening MAP2, the only other important predictors of antepartum hypertension were chronic hypertension and diabetes mellitus. Using these three variables, the probability that an individual pregnant woman will develop antepartum hypertension can be assessed with a high degree of accuracy (84.5%) by 20 weeks of amenorrhea. This assessment is noninvasive and simple to use. Three distinct levels of risk have been defined; the moderate- and high-risk groups warrant careful surveillance during pregnancy and may be reasonable groups in which to test preventive interventions.