Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
U.S. Public Health Service Commissioned Corps, Atlanta, GA, USA.
Matern Child Health J. 2021 Aug;25(8):1242-1253. doi: 10.1007/s10995-021-03149-9. Epub 2021 Apr 30.
Prepregnancy body mass index (BMI) and gestational weight gain (GWG) are known determinants of maternal and child health; calculating both requires an accurate measure of prepregnancy weight. We compared self-reported prepregnancy weight to measured weights to assess reporting bias by maternal and clinical characteristics.
We conducted a retrospective cohort study among pregnant women using electronic health records (EHR) data from Kaiser Permanente Northwest, a non-profit integrated health care system in Oregon and southwest Washington State. We identified women age ≥ 18 years who were pregnant between 2000 and 2010 with self-reported prepregnancy weight, ≥ 2 measured weights between ≤ 365-days-prior-to and ≤ 42-days-after conception, and measured height in their EHR. We compared absolute and relative difference between self-reported weight and two "gold-standards": (1) weight measured closest to conception, and (2) usual weight (mean of weights measured 6-months-prior-to and ≤ 42-days-after conception). Generalized-estimating equations were used to assess predictors of misreport controlling for covariates, which were obtained from the EHR or linkage to birth certificate.
Among the 16,227 included pregnancies, close agreement (± 1 kg or ≤ 2%) between self-reported and closest-measured weight was 44% and 59%, respectively. Overall, self-reported weight averaged 1.3 kg (SD 3.8) less than measured weight. Underreporting was higher among women with elevated BMI category, late prenatal care entry, and pregnancy outcome other than live/stillbirth (p < .05). Using self-reported weight, BMI was correctly classified for 91% of pregnancies, but ranged from 70 to 98% among those with underweight or obesity, respectively. Results were similar using usual weight as gold standard. CONCLUSIONS FOR PRACTICE: Accurate measure of prepregnancy weight is essential for clinical guidance and surveillance efforts that monitor maternal health and evaluate public-health programs. Identification of characteristics associated with misreport of self-reported weight can inform understanding of bias when assessing the influence of prepregnancy BMI or GWG on health outcomes.
孕前体重指数（BMI）和孕期体重增加（GWG）是已知的母婴健康决定因素；计算这两者都需要准确测量孕前体重。我们比较了自我报告的孕前体重与测量体重，以评估母婴特征对报告偏倚的影响。
我们对俄勒冈州和华盛顿州西南部的非营利性综合医疗保健系统 Kaiser Permanente Northwest 的电子健康记录（EHR）数据进行了回顾性队列研究，纳入了年龄≥18 岁、在 2000 年至 2010 年期间怀孕且自我报告了孕前体重、在受孕前≤365 天至≤42 天期间至少测量了两次体重且在 EHR 中测量了身高的女性。我们比较了自我报告的体重与两个“金标准”之间的绝对差异和相对差异：（1）与受孕最接近的体重测量值，以及（2）常体重（受孕前 6 个月和≤42 天内的体重平均值）。使用广义估计方程来评估在控制协变量的情况下，报告错误的预测因素，这些协变量是从 EHR 中获得的，或通过与出生证明的链接获得的。
在纳入的 16227 例妊娠中，自我报告体重与最接近的测量体重之间的一致性（±1kg 或≤2%）分别为 44%和 59%。总的来说，自我报告的体重比测量体重平均低 1.3kg（SD 3.8）。BMI 类别较高、产前保健较晚和妊娠结局不是活胎/死胎的女性报告错误的可能性更高（p<.05）。使用自我报告的体重，91%的妊娠 BMI 得到正确分类，但在体重过轻或肥胖的妊娠中，分别有 70%至 98%的分类正确。使用常体重作为金标准的结果相似。
准确测量孕前体重对于指导临床和监测母婴健康以及评估公共卫生计划的工作至关重要。识别与自我报告体重报告错误相关的特征，可以在评估孕前 BMI 或 GWG 对健康结果的影响时，为理解偏倚提供信息。
