[Clinical backgrounds in two kinds (absolute and relative) of mild pregnancy induced hypertension].

The criteria for pregnancy induced hypertension (PIH) have been determined by the Japanese Obstetrics and Gynecology Society. Mild PIH is classified into two types. One is "Absolute-PIH (A-PIH)" diagnosed by 1) systolic blood pressure (SBP) greater than = 140mmHg and less than 160mmHg or 2) diastolic blood pressure (DBP) greater than = 90mmHg and less than 110mmg. Another one is "Relative-PIH (R-PIH)" diagnosed by 3) an increase in SBP greater than = 30mmHg compared to normal SBP or 4) an increase in DBP greater than = 15mmHg compared to normal DBP. However, there has been no report in which two types of PIH are assessed. Our hypothesis is that the pathophysiology of two types of PIH is different. The purpose of this study is to clarify the pathophysiological difference by evaluating the clinical backgrounds. We evaluated 963 nullipara and 747 multipara whose pregnancies were recorded from the 1st trimester (multiple pregnancy and pre-term delivery before 32 gestational weeks were excluded). Among 765 nullipara women, 79.4% were diagnosed as having normal blood pressure (N-group), 7.1% as A-PIH, and 13.0% as R-PIH. In the multipara N-group, the figures were 632 women (84.6%), A-PIH, 4.6% and R-PIH, 10.3%. Clinical backgrounds showed that the incidence of hypertensive family history, high hematocrit (greater than = 39.0) before the 12th gestational week or obesity (Kaup index greater than = 24 before pregnancy) was significantly higher in A-PIH than in the N-group of nullipara and higher in the A-PIH than in the R-PIH and N-groups of multipara.(ABSTRACT TRUNCATED AT 250 WORDS)