Factors Associated With Inadequate Gestational Weight Gain: A Prospective Multicenter Cohort Study.

Inadequate gestational weight gain (GWG) is associated with birth weight and premature birth and is a primary problem in Asia, particularly in Japan. This study aimed to identify the risk factors associated with inadequate GWG, focusing on women's target GWG and advised GWG by healthcare professionals. A questionnaire for women in their second trimester inquired about their target GWG and advice regarding GWG by healthcare professionals. Of the 626 participants, 52.6% were classified in the inadequate GWG group. Inadequate GWG was associated with a prepregnancy body mass index (BMI) < 18.5 kg/m² and weight below the prepregnancy weight in the second trimester. Among the multiparas, inadequate GWG was associated with an individual target GWG below the guideline, with no advice from healthcare professionals, and with an advised GWG below the guideline. Among the primiparas, there were no significant differences in the individual targets or advised GWG. Healthcare professionals must understand the latest guidelines regarding GWG and apply them when advising women. The importance of preconception care in achieving a BMI of at least 18.5 kg/m² before pregnancy is also suggested.