Low birth weight and its associated factors

ABSTRACT Objective To calculate the frequency and evaluate the factors associated with low birth weight. Methods A retrospective study, with data from pregnant women who participated in the Programa de Atenção às Gestantes do Programa Einstein na Comunidade de Paraisópolis, between 2011 and 2014, and who returned for the postpartum evaluation of their newborns. Variables related to the pregnant woman, pregnancy, and newborn were evaluated. The outcome variable was low birth weight, defined as <2.5kg. The associations between the independent variables and low birth weight were assessed by χ2 and Mann-Whitney tests. Logistic regression models analyzed the combined effects of the independent variables on low birth weight. Results Data of 794 pregnant women and their newborns (52.1% males) were analyzed. The age of pregnant women varied from 13 to 44 years (median of 24 years), and the majority reported being married or living in cohabitation (74.7%), and having between 9 to 11 years of schooling (53.4%). The proportion of low birth weight was 7.6% (newborn mean weight of 3.2kg) and, in multivariate analysis, presence of twinning, age group of the pregnant women (showing protection for low birth weight between ages ≥18 years and <35 years), and cesarean section were associated with low birth weight. Conclusion The proportion of low birth weight was 7.6% and twining, age of the pregnant woman, and cesarean delivery were associated with the occurrence of low birth weight.

摘要
研究目的：旨在计算低出生体重的发生频率，并评估与其相关的影响因素。
研究方法：本研究为回顾性研究，数据来源于2011年至2014年间参与帕拉伊索利斯社区爱因斯坦孕妇关怀项目（Programa de Atenção às Gestantes do Programa Einstein na Comunidade de Paraisópolis）的孕妇，且所有研究对象均完成了新生儿产后随访评估。本研究评估了与孕妇、妊娠及新生儿相关的多项变量，结局变量为低出生体重，定义为新生儿体重＜2.5kg。采用χ²检验与曼-惠特尼（Mann-Whitney）检验分析自变量与低出生体重间的关联，并通过Logistic回归模型分析自变量对低出生体重的联合影响。
研究结果：本研究共纳入794名孕妇及其新生儿进行分析，其中男性新生儿占比52.1%。孕妇年龄跨度为13至44岁，中位年龄为24岁；多数孕妇为已婚或同居状态（74.7%），受教育年限多为9至11年（53.4%）。低出生体重的发生比例为7.6%，新生儿平均体重为3.2kg；多因素分析结果显示，双胎妊娠、孕妇年龄组（18~34岁年龄段可降低低出生体重发生风险）与剖宫产术均与低出生体重存在显著关联。
研究结论：本研究中低出生体重的发生比例为7.6%，双胎妊娠、孕妇年龄与剖宫产分娩均与低出生体重的发生存在相关性。