Division of Neonatal and Developmental Medicine, Stanford University, Stanford, CA, USA.
Division of Epidemiology, University of California, Berkeley, CA, USA.
Am J Clin Nutr. 2020 Apr 1;111(4):845-853. doi: 10.1093/ajcn/nqaa033.
High and low prepregnancy BMI are risk factors for severe maternal morbidity (SMM), but the contribution of gestational weight gain (GWG) is not well understood.
We evaluated associations between GWG and SMM by prepregnancy BMI group.
We analyzed administrative records from 2,483,684 Californian births (2007-2012), utilizing z score charts to standardize GWG for gestational duration. We fit the z scores nonlinearly and categorized GWG as above, within, or below the Institute of Medicine (IOM) recommendations after predicting equivalent GWG at term from the z score charts. SMM was defined using a validated index. Associations were estimated using multivariable logistic regression models.
We found generally shallow U-shaped relations between GWG z score and SMM in all BMI groups, except class 3 obesity (≥40 kg/m2), for which risk was lowest with weight loss. The weight gain amount associated with the lowest risk of SMM was within the IOM recommendations for underweight and class 2 obesity, but above the IOM recommendations for normal weight, overweight, and class 1 obesity. The adjusted risk ratios (RRs) and 95% CIs for GWG below the IOM recommendations, compared with GWG within the recommendations, were the following for underweight, normal weight, overweight, class 1 obesity, class 2 obesity, and class 3 obesity: 1.13 (0.99, 1.29), 1.09 (1.04, 1.14), 1.10 (1.01, 1.19), 1.07 (0.95, 1.21), 1.03 (0.88, 1.22), and 0.89 (0.73, 1.08), respectively. For GWG above the recommendations, the corresponding RRs and 95% CIs were 0.99 (0.84, 1.15), 1.04 (0.99, 1.08), 0.98 (0.92, 1.04), 1.03 (0.95, 1.13), 1.07 (0.94, 1.23), and 1.08 (0.91, 1.30), respectively.
High and low GWG may be modestly associated with increased risk of SMM across BMI groups, except in women with class 3 obesity, for whom low weight gain and weight loss may be associated with decreased risk of SMM.
高孕前 BMI 和低孕前 BMI 是严重产妇发病率（SMM）的危险因素，但妊娠体重增加（GWG）的作用尚不清楚。
我们评估了 GWG 与不同孕前 BMI 组 SMM 之间的关联。
我们分析了来自加利福尼亚州 2483684 例出生记录（2007-2012 年），利用 z 评分图表将 GWG 标准化为妊娠持续时间。我们将 z 评分非线性拟合，并在从 z 评分图表预测足月时的等效 GWG 后，将 GWG 分类为高于、等于或低于医学研究所（IOM）建议。SMM 采用验证指数定义。使用多变量逻辑回归模型估计关联。
我们发现，除了 3 级肥胖（≥40kg/m2）外，GWG z 评分与所有 BMI 组中的 SMM 之间普遍存在浅 U 型关系，对于 3 级肥胖，体重减轻与 SMM 风险最低相关。与 IOM 建议范围内的 GWG 相比，与 SMM 风险最低相关的 GWG 增加量在低体重和 2 级肥胖范围内，但高于正常体重、超重和 1 级肥胖的 IOM 建议。与 IOM 建议范围内的 GWG 相比，GWG 低于 IOM 建议的调整风险比（RR）和 95%置信区间（CI）如下：低体重组 1.13（0.99，1.29）、正常体重组 1.09（1.04，1.14）、超重组 1.10（1.01，1.19）、1 级肥胖组 1.07（0.95，1.21）、2 级肥胖组 1.03（0.88，1.22）和 3 级肥胖组 0.89（0.73，1.08）。对于 GWG 高于建议范围，相应的 RR 和 95%CI 分别为 0.99（0.84，1.15）、1.04（0.99，1.08）、0.98（0.92，1.04）、1.03（0.95，1.13）、1.07（0.94，1.23）和 1.08（0.91，1.30）。
高 GWG 和低 GWG 可能与各 BMI 组 SMM 风险增加适度相关，除了 3 级肥胖的妇女外，对于体重增加和体重减轻与 SMM 风险降低相关的妇女，低体重增加和体重减轻可能与 SMM 风险降低相关。
