Background: The effect of maternal weights on the risk of iron deficiency anemia (IDA) during pregnancy remains unclear. The study aimed to investigate the association between maternal weight indicators and IDA during pregnancy.
Methods: We conducted a cohort study to examine the association between maternal weight indicators, including prepregnancy body mass index and the rate of gestational weight gain (GWG), and the risk of IDA among Chinese pregnant women. Data about new-onset IDA at different trimesters from a national cross-sectional survey were collected; information regarding baseline variables and rate of GWG from women participating in the survey were retrospectively collected. Tested IDA and reported IDA were documented. Multilevel logistic regression to examine the association between maternal weight indicators and the risk of IDA after adjusting for potential confounders was conducted.
Results: This study enrolled 11,782 pregnant women from 24 hospitals from September 19, 2016, to November 20, 2016. Among those, 1515 (12.9%) IDA events were diagnosed through test (test IDA); 3915 (33.3%) were identified through test and patient reporting (composite IDA). After adjusting for confounders and cluster effect of hospitals, underweight pregnant women, compared with normal women, were associated with higher risk of test IDA (adjusted odds ratio [aOR]: 1.35, 95% confidence interval [CI]: 1.17-1.57 and composite IDA (aOR: 1.35, 95% CI: 1.21-1.51); on the contrary, overweight and obese women had lower risk of test IDA (aOR: 0.68, 95% CI: 0.54-0.86 overweight; aOR: 0.30, 95% CI: 0.13-0.69 obese) and composite IDA (aOR: 0.77, 95% CI: 0.67-0.90 overweight; aOR: 0.34, 95% CI: 0.21-0.55 obese). The higher rate of GWG was associated with higher risk of IDA (test aOR: 1.86 95% CI: 1.26-2.76; composite aOR: 1.54, 95% CI: 1.16-2.03).
Conclusions: Pregnant women who are underweight before pregnancy and who have faster GWG are more likely to develop IDA. Enforced weight control during pregnancy and use of iron supplements, particularly among underweight women, may be warranted.
孕妇体重与孕期缺铁性贫血的相关性研究：基于一项队列研究的结果 摘要 背景：孕妇体重对孕期缺铁性贫血的影响仍然是不清楚的，本文旨在调查孕妇体重与孕期缺铁性贫血的相关性。 方法：我们在中国实施了一项队列研究来评估孕妇体重与孕期缺铁性贫血的相关性，孕妇体重包括孕前体重指数和孕期体重增长速度两个指标。其中，不同孕期缺铁性贫血的诊断数据来自一项全国性的横断面研究，我们同时考察了经实验室诊断的缺铁性贫血和孕妇自报的缺铁性贫血。此外，我们回顾性收集了相关基线信息（孕前体重指数）和孕期体重增长速度。我们采用多水平logistic模型来评估孕妇体重与孕期缺铁性贫血的相关性并控制潜在混杂因素的影响。 结果：从2016年9月19日到2016年11月20日，我们从中国24家医院总共纳入11,782例孕妇。其中，1515 （12.9%）例发生经实验室诊断的缺铁性贫血，3915 （33.3%）发生复合缺铁性贫血（经实验室诊断和孕妇自报任意一种情况）。在调整了混杂和医院间的聚集效应后，我们发现：孕前低体重孕妇，相比于孕前体重正常孕妇，有更高的缺铁性贫血风险（实验室诊断缺铁性贫血：aOR:1.35, 95%CI :1.17-1.57 ；复合缺铁性贫血：aOR: 1.35, 95%CI :1.21-1.51）；相反，孕前超重和肥胖的孕妇有更低的经实验室诊断的缺铁性贫血风险（超重：aOR: 0.68, 95%CI: 0.54-0.86; 肥胖：aOR 0.30, 95%CI 0.13-0.69）和复合缺铁性贫血风险（超重：aOR: 0.77, 95%CI: 0.67-0.90; 肥胖：aOR: 0.34, 95%CI:0.21-0.55）。此外，更快的孕期体重增长速度也与缺铁性贫血的风险呈正相关（实验室诊断缺铁性贫血： aOR: 1.86, 95%CI: 1.26-2.76; 复合缺铁性贫血：aOR: 1.54, 95%CI :1.16-2.03）。 结论：孕妇孕前低体重和孕期体重增长速度过快更容易发生孕期缺铁性贫血，对上述人群应加强孕期体重管理和补充铁元素。.
Keywords: Gestational Weight Gain; Iron Deficiency Anemia; Prepregnancy Body Mass Index.