Analysis On Pregnancy Outcomes Of Fetal Isolated Short Femur In Second And Third Trimester

Objective:The aim of this study is to analyse the dynamic ultrasound results of the isolated short femur（ISF）fetus in the second and third trimesters and the pregnancy outcome of the maternal and children,and explore the relationship between ISF and maternal and children adverse pregnancy outcome.It is expected to provide reference evidence for perinatal management of such fetuses and pregnant women.Methods:The clinical data of puerpera with singleton pregnancy whose fetuses had been diagnosed as ISF（femur length<the 5th percentile,abdominal circumference>or=the 10th percentile）by prenatal ultrasound during the second and third trimester in Fujian Provincial Maternity and Childen’s Hospital during January 1,2017 to December 31,2019 was collected.Among the 860 fetuses with ISF in total,6 fetuses with genetic abnormalities in interventional prenatal diagnosis were excluded,and854 fetuses with ISF were regarded as the case group.According to the gestational week of ultrasound diagnosis of ISF,they were divided into 3 groups:<28 weeks,28to 33⁺⁶weeks,and 34 to 36⁺⁶weeks.Case control study was conducted to randomly select 854 cases of fetuses with regular perinatal examinations in our hospital during the same time period,normal prenatal ultrasound examination(FL>or=P₅,AC>or=P₁₀)and low risk prenatal screening as the control groups accordance with age and gestational weeks at a ratio of 1:1 to analyze the relationship of isolated short femur with maternal and child pregnancy outcome.Fisher’s exact test,the chi-square test and t test were conducted with SPSS 22.0 statistical software.Results:1.From January 2017 to December 2019,the total number of pregnant women who gave birth to singletons in the Fujian Provincial Maternity and Childen’s Hospital was 53421.A total of 860 cases of ISF fetuses were diagnosed by prenatal ultrasound,with an incidence rate of 1.61%,and the gestational weeks of diagnosis were from 21⁺³to 36⁺⁶weeks.There were 112 cases of ISF fetuses were found in the second trimester（<28 weeks）,and 748 ISF fetuses in the third trimester(28 to 36⁺⁶weeks),the incidence rates were 0.21%（112 in 53421）and 1.40%（748 in 53421）respectively.ISF mostly occurs in the third trimester.There were 95 cases of ISF fetuses underwent interventional prenatal diagnosis due to advanced age or high risk of serological screening or non-invasive DNA or significantly shortened femur.There were 6 cases（6.32%）of genetic abnormalities,including 1 case of 21-trisomy syndrome,1 case of skeletal dysplasia,and 3 cases Chromosome mosaicism and 1case of chromosome 21 double satellite.2.Excluding 6 fetuses with genetic abnormalities,there were 854 cases in the ISF case group,109 cases in the<28 weeks group,639 cases in the 28 to 33⁺⁶weeks group,and 106 cases in the 34 to 36⁺⁶weeks group.In the three groups of ultrasound follow-up,the incidence of fetal persistent short femur was 6.70%（40 in 109）,38.18%（244 in 639）,46.23%（49in 106）,respectively.The incidence of transient short femur was 63.3%（69 in 109）,61.82%（395 in 639）and 53.77%（57 in 106）respectively.In the three groups,the incidence of fetal abdominal circumference changing from AC≥P₁₀to AC<P₁₀was 17.43%（19 in 109）,9.08%（58 in 639）,and7.55%（8 in 106）respectively.The time from finding FL<P₅and AC>or=P₁₀to AC<P₁₀was（9.82±3.29）,（4.85±1.80）,（2.88±1.07）weeks respectively.3.The age of the pregnant women in the ISF case group was（30.30±4.17）years,the height was（157.95±5.20）cm,and the gestational week of delivery was（39.22±1.69）weeks.The height of the pregnant women was lower than that of the control group,and the difference was statistically significant（P<0.05）.The birth weight of ISF newborns was（3138.47±425.56）g and the length was（48.66±1.99）cm,which was lower than the control group.The incidence of premature delivery,small-for-gestational age infants,fetal distress,preeclampsia and emergency cesarean sectionwere higher than the control Group（P<0.05）.4.In the<28 weeks,28 to 33⁺⁶weeks and 34 to 36⁺⁶weeks group,the incidence of preeclampsia decreased successively,which were 6.4%（7 in 109）,2.7%（17 in639）,0.9%（1 in 106）respectively,which decreased in turn（P<0.05）.5.In the<34 weeks group,the birth weight of persistent short femur fetuses was（3052.04±393.89）g,and the length was（48.24±1.88）cm,which was lower than that of transient short femur fetuses,the incidence of smaller than gestational age infants,premature birth,and fetal distress were higher than transient short femur fetuses（P<0.05）.In the 34 to 36⁺⁶weeks group,there were no statistically significant differences between the persistent short femur and the transient short femur,fetus for pregnancy outcomes such as newborn birth weight,length,small for gestational age,premature birth,preeclampsia,and fetal distress（P>0.05）.Conclusions:1.ISF was a common clinical ultrasound"soft index".Most fetus with the isolated short femur were related to mother’s height,and had a good prognosis.2.Interventional prenatal diagnosis was recommended when the ISF fetus in the second trimesterhas one or more of the following abnormalities:1)advanced age;2)high risk of serological screening or non-invasive DNA;3)significant shortening of the fetal femur.3.ISF was related to adverse pregnancy outcomes such as small for gestational age,premature birth,preeclampsia,emergency cesarean section,and fetal distress.The earlier occurrence of fetal ISF,the incidence of preeclampsia in pregnant women was higher.The longer duration of ISF,the incidence of infants smaller than gestational age was higher.4.Attention should be paid to the perinatal management of ISF,and it was recommended to include ISF in the scope of high-risk pregnancy supervision to reduce the occurrence of adverse pregnancy outcomes.