| Objective:To investigate the trend of body composition and PhA during pregnancy among overweight/obese and non-overweight pregnant women;and to analyze the association of the increase of body composition with GWG and the rate of GWG in each trimester,and to analyze the factors of phase angle at late pregnancy and the relationship between phase angle at late pregnancy and weight gain.Methods:This study was a retrospective cohort study with objects registered in nutritional department of Peking Union Medical College Hospital and Shunyi maternal and child health care hospital from 2018 to 2019.Pre-pregnancy information including height,age,pre-pregnancy weight and BMI and parity et,al were obtained from patient reports at first visit.Body composition and PhA at the end of first trimester(8-14 weeks),second trimester(20-28 weeks)and third trimester(>35 weeks)were measured using an Inbody 770 instrument based on BIA technology.The GWG and tri-rGWG were calculated.Repeated measures ANOVA was used to analyze the trend of body composition and PhA during pregnancy in overweight and non-overweight pregnant women and the interaction effect of pre-pregnancy BMI and period.Multivariate line regression analysis was used to study the association of the increment of body composition,PhA in late pregnancy with GWG and the rate of GWG in each trimester,and to control confounders.Results:a)A total of 141 pregnant women aged from 23 to 44 years with a median prepregnancy BMI of 22.5(5.38)kg/m2 were recruited in the study,of whom 53 exceeded 24kg/m2,representing 37.6%.Average GWG was 13.92±5.15 kg,of which,15(10.6%)were underweight,53(37.6%)had appropriate weight gain,and 73(51.8%)had excessive weight gain.There were 55(39%)women who had excessive rGWG in the second trimester and the number in the third trimester was 88(62.4%).b)Both period and pre-pregnancy BMI were independent effect factors for changes in body composition during pregnancy.All body components,including BFM/PFM,FFM,TBW,ICW,ECW,protein,skeletal muscle,and minerals increase with trimester of gestation after 14 weeks of gestation.Among which,the body fat mass of the overweight/obese group and the non-overweight group in the first,second and third period of pregnancy were 27.59±5.22 kg/16.97±4.17 kg,29.61± 5.24 kg/19.91± 4.09 kg,and 32.18±5.66 kg/23.4±4.48 kg,respectively,with significant differences between different period;The fat free mass were 44.44±3.92 kg/38.63 ± 3.62 kg,47.07±4.19 kg/41.31± 4.04 kg,and 50.75± 4.25 kg/45.99± 4.31 kg,respectively.The differences in body composition between different time points were statistically significant(P<0.001).The body components were significantly higher in the overweight/obese group than the non-overweight group.The growth of body composition in non-overweight group were significantly higher than the overweight/obese group.The growth during the third trimester was higher than in second trimester.There was a significant interaction effect of period and pre-pregnancy BMI.c)GWG significantly affected BFM and FFM gain,adjusting age,pre-pregnancy BMI,parity and initial values of body composition.The rGWG during the second and third trimester significantly affected the growth of BFM and FFM,after adjustment for age,pre-pregnancy BMI,the initial value of body composition in the first trimester.d)The PhA decreased during the second trimester and increased in the third trimester,and the difference between first and second trimester was significant only observed in the overweight group.PhA were significantly higher at all times in overweight group than non-overweight group.There was a significant interaction effect of pre-pregnancy BMI and period on PhA.e)There was a significant positive correlation between PhA and ICW,protein,and skeletal muscle in the third trimester,and a significant negative correlation between phase angle and ECW/TBW.After adjustment for the initial values of pre-pregnancy BMI,age,and PhA in first trimester,the rGWG in second trimester significantly affected PhA in the third trimester.Conclusion:Pre-pregnancy overweight and excessive GWG are relatively common.The body composition in overweight group was significantly higher.The maternal BFM and FFM increase significantly during pregnancy,and the increase was higher in the third trimester than in the second trimester.Women who were not overweight had a greater increase in body composition than overweight women.GWG and rGWG during the second and third trimester can significantly affect body composition growth.Therefore,an appropriate BMI before pregnancy,as well as a proper GWG during pregnancy,are crucial.The PhA showed a decrease and then an increase during pregnancy.The PhA in third trimester is a proxy of the value of body protein and the proportion of ECW.PhA was affected by weight gain during the second trimester.The nutrition of pregnant women can be known to some extent by studying the phase angle. |
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