Plasma Ferritin Levels In Early And Middle Pregnancy And The Risk Of Fetal Growth

Objective:Our study aimed to explore the association of Plasma ferritin?PF?levels in early and middle pregnancy and the risk of fetal growth and birth outcomes.Methods:Pregnant women with single alive pregnancy were enrolled between January,2013 and December,2016,who signed the informed consent and began the whole follow-up of their own initiative ranging 8-16 gestational weeks.Firstly,the basic information about our women were obtained through a delicately designed questionnaire.Besides,blood samples were collected at 6-18 gestational weeks and then measured for PF.Several indicators of fetal intrauterine growth were acquired by the B-ultra sound test during the follow-up as well as birth weight and length during 18-26gestational weeks and 28-34 gestational weeks,respectively.PF levels were grouped according to tertiles of our population as low,middle and high PF groups.Univariate analysis was used to compare the basic characteristics,indicators of fetal growth,birth weight and length.Multivariate linear regression analysis was used to analyse the effects of Plasma ferritin levels in early and middle pregnancy on the risk of fetal growth indicators as well as birth weight and length.Mixed linear models were used to analyse the effects of PF levels on fetal weight in middle and late pregnancy and at birth longitudinally.We also used stratification analysis according to age,prepregnancy BMI,primiparity,hemoglobin levels.Logistic regression models were used to analyse the association between PF and small for gestational age babies.Results:738 women were matched for this study.Their age was 29.1±3.2 years old.Height was 160.2±5.0 cm.Prepregnancy BMI was 21.1±2.7 kg/?.There was a percentage of 81.7%for nulliparous women.The median value of PF was 69.8?g/L with the first tertile was 43.6?g/L and the third tertile was 123.7?g/L.The gestational weeks of blood collection was 12.8±1.7w.Among the 738 mother and baby pairs,male infants were 55.42%?n=409?and female infants were 44.58%?n=329?with delivery weeks of39.3±1.5 w,birth weight of 3341±430.6g and birth length of 50.1±1.5cm.PF values were grouped as Low??52.59?g/L?,middle?52.59⁹8.66?g/L?and high??98.66?g/L?PF groups.With the middle group as reference,confounding factors were adjusted by multivariate linear regression analysis and when compared to the middle group,fetals in low PF group were found to have smaller biparietal diameter??:-0.07?-0.12,-0.01?,P=0.012?and head circumference??:-0.19?-0.35,-0.03?,P=0.021?in the middle pregnancy while in late pregnancy,smaller biparietal diameter??:-0.07?-0.13,-0.01?,P=0.014?and lower birth weight??:-89.3?-159.11,-19.48?,P=0.012?were observed.Otherwise in comparison between high and middle PF groups,only smaller biparietal diameter??:-0.17?-0.34,0.00?,P=0.045?was observed in the middle pregnancy while lower estimated foetal weight??:-36.45?-68.6,-4.30?,P=0.026?and birth weight??:-118.02?-188.67,-47.38?,P=0.001?and smaller biparietal diameter??:-0.07?-0.13,-0.01?,P=0.016?,head circumference??:-0.20?-0.37,-0.03?,P=0.023?and abdominal circumference??:-0.30?-0.53,-0.08?,P=0.009?in late pregnancy were observed.Mixed linear models were used and we found that longitudinal weight gain of both the low PF??:-39.86?-72.70,-7.02?,P=0.017?and high PF groups??:-57.23?-90.71,-23.74?,P=0.001?were lower than the middle group.According to the stratification analysis results,male fetals might be more effected by low PF levels while female fetals might be more effected by high PF levels both with significant differences(P _interaction=0.048).Conclusions:Low or high PF levels for pregnant women might increase the risks of decreased fetal growth.Women with inappropriate PF levels might gave birth to lighter and shorter babies.