Low birth weight and abnormal pre-pregnancy body mass index were at higher risk for hypertensive disorders of pregnancy

Low birth weight is known to be associated with hypertension, cardiovascular disease and hypertensive disorders of pregnancy (HDP); however, this association might vary by race/ethnicity. This study aimed to clarify the association between women's own birth weight and their subsequent risk for HDP in a Japanese population, in combination with pre-pregnancy body mass index (BMI). We conducted a cohort study as part of the Tohoku Medical Megabank Birth and Three-Generation Cohort Study in Miyagi, Japan. Our study's population included 4810 women. A multivariate logistic regression analysis was performed to calculate the adjusted odds ratio (aOR) and the 95% confidence interval (CI) of the women's own birth weight for HDP, in the combination categories of birth weight and pre-pregnancy BMI. As a result, the group with a low birth weight of <2500 g had a significant association with HDP (the aOR, 1.50; 95% CI, 1.02–2.21). In the subtype analysis, the odds ratio for only preeclampsia was significantly increased in the low birth weight group (aOR, 3.37; 95% CI, 1.84–6.16). In the group with a low birth weight, the prevalence of HDP was higher in both the underweight and overweight groups. In conclusion, there was a significant association between low birth weight and subsequent HDP in Japanese women. Furthermore, a significant association with HDP was found for women born with a low birth weight who were underweight or overweight as adults. Maintaining a normal weight may be effective for preventing HDP even if a woman was born small.