Optimal Weight Gain During Pregnancy in Japanese Women

BACKGROUND: In order to examine the optimal weight gain during pregnancy in Japanese women, we analyzed the perinatal outcomes in Japanese women with the optimal range of weight gain during pregnancy according to the Japanese (the Japanese Ministry of Health, Labour and Welfare: JMHLW and the Japan Society for the Study of Obesity: JASSO) guidelines compared with those according to the USA (the Institute of Medicine: IOM) guideline. METHODS: We compared the obstetric outcomes in two groups of gestational weight gain within the optimal range based on the IOM and Japanese guidelines in women of pre-pregnancy body mass index (BMI) categories of underweight, normal, overweight and obese. RESULTS: In the underweight and normal-weight women, the incidences of preterm delivery and low-birth-weight infant in the JMHLW group were significantly higher than those in the IOM group; however, the incidence of some other perinatal complications in the JMHLW group was significantly lower than that in the IOM group. In the overweight women, the incidences of preterm delivery and low-birth-weight infant in the JSSO group were significantly higher than those in the IOM group; however, there were no significant differences in the obstetric outcomes between the obese women in the JSSO and IOM groups. CONCLUSION: Based on the current results, we should be more tolerant for the weight gain during pregnancy in Japanese woman than ever, especially in overweight women.