Study On The Relationship Between Gestational Weight Gain Trajectories And Pregnancy Complications Based On Latent Class Growth Model

Objective1 To investigate the trajectory of maternal weight change throughout pregnancy and the factors influencing it.2 To investigate the effect of different pre-pregnancy body mass index types on the trajectory of weight change during pregnancy.3 To investigate the trajectory of gestational weight change and the factors influencing it in pregnant women with Gestational Diabetes Mellitus or Hypertensive Disorders of Pregnancy.MethodsIn this study,women with gestational weeks≤12⁺⁶ weeks who had regular obstetric checkups at the Obstetrics Clinic of the Affiliated Hospital of Qingdao University between July 1,2021 and March 31,2022 and who were scheduled to deliver at the hospital were selected as the study population strictly according to the inclusion and exclusion criteria using a self-designed general information questionnaire and follow-up data collection form for baseline data and follow-up data（weight data）were collected every 4 weeks until the end of delivery.The weight data obtained at the follow-up visits were fitted with a Latent Class Growth Model using SAS 9.4 software,and the baseline data of the different trajectory subgroups were compared using statistical methods such as chi-square test,ANOVA and logistic regression using SPSS 26.0 to investigate the influencing factors of the different trajectory subgroups.The trajectories of gestational weight change were fitted again after grouping according to different pre-pregnancy body mass index types,and the differences between the trajectories of gestational weight change of study subjects with different pre-pregnancy body mass index types and all study subjects were compared to investigate the effects of different pre-pregnancy body mass index types on the shape and growth trend of gestational weight change trajectories.The trajectories of gestational weight change in pregnant women with Gestational Diabetes Mellitus or Hypertensive Disorders of Pregnancy were fitted according to whether they had Gestational Diabetes Mellitus or Hypertensive Disorders of Pregnancy,and the factors influencing the trajectories of different disease trajectories were investigated.ResultsA total of 1496 study subjects were included in this study,and there existed three subgroups of their trajectories of weight change during pregnancy,which accounted for42.65%,44.12%,and 7.14%,respectively,according to the low to high weight gain during pregnancy,and the initial weight of pregnant women determined the intercept of the trajectory,and the greater the initial weight,the faster the rate of weight gain,and there was only one turning point for the change in the rate of weight gain during pregnancy,which occurred at about 12 weeks of gestation.The rate of weight gain accelerates significantly after the turning point.The factors influencing the trajectories of weight change in different gestational periods were:height,number of births,pre-pregnancy body mass index,per capita monthly household income,presence of health insurance,occupation,regular menstrual cycle,previous hypertensive disorders in pregnancy,presence of polycystic ovary syndrome,and family history of diabetes in the immediate family（P<0.05）.The trajectories of gestational weight change in pre-pregnancy low weight,normal weight,overweight and obese study subjects could be fitted into 3 subgroups,2 subgroups,3 subgroups and 3 subgroups with the same shape and growth trend as the trajectories of gestational weight change in all study subjects,but with different number of subgroups,respectively.287（19.20%）study subjects had gestational diabetes mellitus,276（18.40%）had gestational hypertensive disorders,and five subgroups existed in the trajectory of gestational weight change in study subjects with Gestational Diabetes Mellitus,accounting for 26.83%,31.01%,25.09%,11.50%,and 5.57%,respectively,with statistically different general characteristics of:Height,pregnancy frequency,mode of conception,type of body mass index before pregnancy,blood type,place of residence,health insurance,menstrual cycle regularity,previous HDP,and alcohol consumption within 3 months before pregnancy（p<0.05）;four subgroups existed in the trajectory of weight change during pregnancy in study subjects with Hypertensive Disorders of Pregnancy,accounting for 31.52%,33.69%,26.09%,and 8.70%,respectively,with statistically different the general characteristics of the subjects were:height,type of pre-pregnancy body mass index,education,regularity of menstrual cycle,previous sufferings from HDP,sufferings from PCOS,and history of diabetes in the immediate family（P<0.05）.Conclusion1 There are 3 trajectory subgroups of maternal gestational weight change trajectories,with the greater the initial weight,the faster the weight gain,and after 12 weeks of gestation,the weight gain accelerates,influenced by height,occupation and other factors.2 The shape and trend of the trajectory of gestational weight change in pregnant women with different pre-pregnancy body mass index types were the same as the trajectory of gestational weight change in pregnant women.3 There were 5 and 4 trajectory subgroups of gestational weight gain change trajectories in pregnant women with Gestational Diabetes Mellitus or Hypertensive Disorders of Pregnancy,influenced by factors such as height and previous HDP.