壮族地区孕妇体重增长变化轨迹潜变量增长模型分析

Trajectory of gestational weight gain in Zhuang ethnic pregnant women:an latent class growth model analysis

目的探讨母亲孕期体重增长是否存在不同模式,考察孕前体质指数(BMI)对孕妇体重轨迹变化的影响。方法广西壮族孕妇前瞻性出生队列作为研究基础,选择2015年2月—2018年4月收自平果、隆安、德保、田东等县级医院共2409人,获取研究对象基本人口学信息、产检信息,运用潜变量增长模型、Wald检验和χ^2检验进行分析。结果在不分组的模型拟合中,确定了4条不同的孕期体重增长轨迹(人数比例:A组566人,B组1047人,C组624人,D组172人),各组均在孕10周出现速率转折点,初始体重越高的孕妇,年龄越大(P<0.05)、城市居住(P<0.001)、较大孕前BMI(P<0.001)和规律运动(P=0.088)的比例越高。在按孕妇孕前BMI分组的模型拟合中,低体重组、正常组、超重组孕妇均可分别拟合多个亚型,曲线截距差异与斜率差异均有统计学意义(均P<0.001),均有初始体重越大,增速越快。结论广西壮族地区孕妇孕10周后体重增长速率加快;孕前体重越大的孕妇,孕早期体重增速越快。壮族孕妇孕期体重增加可能具有一定的民族和地方特点,在制定周体重增加率的推荐标准时应考虑拐点的不同。城市妇女、年龄越大,孕期体重增长速率越快。应加强对城市大龄超重孕妇孕期体重的监测。

Objective To explore whether there are different patterns in gestational weight gain(GWG)among pregnant women,and to investigate the effect of pre-pregnancy body mass index(BMI)on the changes in pregnant women′s weight.Methods From the participants of the prospective birth cohort of pregnant women in Guangxi Zhuang Autonomous Region(Guangxi),we selected 2409 women having maternal care services at county hospitals in four counties of Guangxi for the study from February 2015 through April 2018.Demographic information and the prenatal examination records were collected for all the women.Latent class growth mode(LCGM),Wald test,andχ^2 test were used in data analyses.Results For all the women,four different GWG trajectories during pregnancy were identified,which covered 23.50%,43.46%,25.90%,and 7.14%of the women with different pre-pregnancy weight from low to high;each of the trajectories presented a turning point of weight gain rate at 10 gestational weeks.The women at elder age were more likely to have a greater pre-pregnancy weight(P<0.05);higher proportion of high pre-pregnancy weight was observed among the women living in urban areas(P<0.001),having higher pregnancy BMI(P<0.001),and doing physical exercise regularly(P=0.088).Various GWG trajectories were established for the three groups of the women with low,normal,and high pre-pregnancy BMI using LCGM analysis and the intercepts and the slopes of the trajectories were significantly different from each other(P<0.001 for all);while,the slope was positively correlated with the intercept for all the trajectories established.Conclusion Among Zhuang pregnant women,gestational weight gain would be accelerated at 10 gestational weeks and the women with higher pre-pregnancy weight could have a faster weight gain during early pregnancy.The study results suggest a closer monitoring on body weight among the pregnant women at elder age and those with pre-pregnancy weight.