Investigation of optimal weight gain during pregnancy for Japanese Women.

This study aims to compare the US Institute of Medicine (IOM) and Japanese guidelines proposed by the Ministry and the Japan Society for the Study of Obesity on gestational weight gain (GWG), and to explore the optimal GWG range in Japanese women. We investigated 8,152 Japanese women who had full-term singleton babies between 2010 and 2013 at a single center in Tokyo. Logistic regression models showed that GWG below the recommendation of the IOM and Japanese guidelines was similarly associated with an increased risk of light-for-date (LFD), whereas GWG above these guidelines was similarly associated with an increased risk of heavy-for-date (HFD) in pre-pregnancy body mass index categories of underweight (<18.5 kg/m2 , n = 1559), normal-weight (18.5-24.9 kg/m2 , n = 4998), overweight (25.0-29.9 kg/m2 , n = 270), and obese (30 ≤ kg/m2 , n = 60). The receiver-operating characteristic curve demonstrated that the optimal cutoffs for LFD and HFD were 9.7 and 10.4 kg, respectively in normal-weight mothers. The IOM and Japanese guidelines identified the risk of LFD or HFD equally well. The optimal GWG range in normal-weight women observed in this study was more close to Japanese guideline (i.e., 7-12 kg) compared to the IOM guideline (i.e., 11.5-16 kg).