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ry of hypertension, previous history of pregnancy-induced hypertension, pre-exciting diabetes, ges-tational diabetes mellitus, maternal age ≥40 years, multiple pregnancies, nulliparity, and pre-pregnan-cy obesity (5-10). Some prior studies have suggested that higher pre-pregnancy body mass index is asso-ciated with increased risk of gestational hyperten-sion and pre-eclampsia (11-15). However, there are a few studies in which this association was not ob-served (16). Also, excessive gestational weight gain has been proposed as a risk factor of hypertensive disorders of pregnancy in some studies (17-20). PIH is accompanied with endothelial dysfunction, oxi-dative stress, and inflammatory responses (1). It has been claimed that plasma C-reactive protein con-centration, which may be involved in an aetiology of hypertensive disorder of pregnancy increased in obesity. Furthermore, some evidences have indicat-ed that obesity increased endothelial function and prompted systematic inflammatory responses asso-ciated with atherosclerosis, which could play a role in PIH (21). However, previous studies are limited by improper classification of gestational weigh