Division of Neonatology, National Center for Child Health and Development, Tokyo, Japan.
Division of Health Policy, National Center for Child Health and Development, Tokyo, Japan.
J Obstet Gynaecol Res. 2024 Aug;50(8):1295-1301. doi: 10.1111/jog.15973. Epub 2024 May 19.
For women, being underweight increases their susceptibility to osteoporosis, anemia, and other conditions and affects the weight of their infants and the well-being of future generations. This study examined the association between low pre-pregnancy body mass index (BMI) and low birthweight using health insurance claims data and health checkup data, including weight measurements.
We used health insurance claims data and health checkup data (JMDC, Tokyo, Japan) of women and their newborns in Japan between 2006 and 2020. We used checkup data, which included more accurate weight measurements and blood test-based diagnoses of anemia and hyperlipidemia compared to self-reported data. Maternal pre-pregnancy BMI was compared across three groups: underweight (BMI <18.5 kg/m), normal weight (BMI 18.5-24.9 kg/m), and overweight (BMI ≥25.0 kg/m). The primary outcome was low birthweight (<2500 g), and secondary outcome was preterm childbirth. Logistic regression analyses were conducted to compare outcomes in the three groups by BMI. The underweight BMI group was considered as the reference group. A subgroup analysis was performed by maternal age.
In total, 16 363 mothers (underweight, 3418 [21%], normal weight, 11 493 [70%], and overweight, 1452 [8.9%]) were included. The risk of primary outcome (low birthweight) was significantly lower in the normal weight group than in the underweight group (4.6% vs. 5.7%; adjusted odds ratio 0.78 [95% confidence interval: 0.65-0.96]). In the subgroup analyses, no significant differences were noted in the incidences of low birthweight and preterm childbirth between maternal age groups.
Pre-pregnancy BMI was associated with an increased risk of delivering low-birthweight infant. Awareness about the importance of women's pre-pregnancy health and appropriate BMI may reduce the incidence of low birthweight.
对于女性来说，体重过轻会增加其骨质疏松、贫血和其他疾病的易感性，并影响婴儿的体重和后代的健康。本研究使用健康保险索赔数据和健康检查数据（日本东京 JMDC），包括体重测量，调查了孕前体重指数（BMI）较低与低出生体重之间的关系。
我们使用了 2006 年至 2020 年期间日本女性及其新生儿的健康保险索赔数据和健康检查数据（JMDC，东京，日本）。与自我报告数据相比，健康检查数据包含了更准确的体重测量和基于血液检查的贫血和高血脂症诊断。将母亲的孕前 BMI 分为三组：体重过轻（BMI<18.5kg/m²）、正常体重（BMI 18.5-24.9kg/m²）和超重（BMI≥25.0kg/m²）。主要结局是低出生体重（<2500g），次要结局是早产。采用 logistic 回归分析比较三组 BMI 的结局。体重过轻 BMI 组为参考组。还进行了按母亲年龄的亚组分析。
共纳入 16363 名母亲（体重过轻 3418 名[21%]，正常体重 11493 名[70%]，超重 1452 名[8.9%]）。与体重过轻组相比，正常体重组的主要结局（低出生体重）风险显著降低（4.6%比 5.7%；调整后的优势比 0.78[95%置信区间：0.65-0.96]）。在亚组分析中，不同年龄组的低出生体重和早产发生率无显著差异。
孕前 BMI 与低出生体重儿的风险增加相关。提高对女性孕前健康和适当 BMI 的认识，可能会降低低出生体重的发生率。
