Risk factors for the occurrence of pregnancy-induced hypertension

Risk factors for pregnancy-induced hypertension (PIH) were assessed using a computerized data base on 28,838 women delivering at Parkland Memorial Hospital between 1978 and 1980. Of the total sample, 5,190 (18% developed PIH, defined as diastolic blood pressure > 90 mmHg on more than one occasion measured at least 8 hours apart. Odds ratios for potential risk factors for PIH, as selected from a literature review, were estimated using multiple logistic regression. Our results were indicative that: (1) Age had a linear (not U-shaped) relation with PIH after adjusting for parity; (2) PIH was twice as likely to occur if chronic hypertension were present, controlling for all other variables; (3) Diabetes did not have a significant association with PIH, controlling for chronic hypertension and other variables; and (4) Heart disease, renal disease, race and multiple gestation had important independent effects on PIH.