胎儿肢骨发育异常18例产前诊断

目的 探讨胎儿肢骨发育异常的产前诊断方法.方法 选择2006年1月至2009年12月在首都医科大学附属北京妇产医院就诊,首次B超检查提示胎儿长骨长度小于相应孕周均值的2个标准差(2SD)或长骨发生成角改变,或B超检查提示胎儿合并其他畸形的孕妇18例.采用B超测量胎儿双顶径(BPD)、股骨长(FL)、腹围(AC)、头围(HC)、肱骨长(HL)、羊水指数(AFI)以及脏器结构,计算FL/AC以及长骨生长速度.软骨发育异常按如下标准:胎儿FL、HL小于相应孕周的4SD,或FL/AC＜0.16;成骨发育不全按如下标准:X线摄片显示胎儿四肢长骨短小而粗,长骨弯曲成角,有宫内骨折发生,胎儿颅骨薄或有塌陷.结果 (1)胎儿B超及X线检查:18例胎儿中,7例HC＞同孕周2SD,10例合并羊水过多,12例羊水指数＞18.0,9例合并胸腔狭小、脊柱排列结构紊乱及心脏结构异常等畸形.例1～14为软骨发育不全,其中11例胎儿FL和HL均＜同孕周4SD;2例FL＜同孕周3SD,HL＜同孕周4SD;1例FL仅＜同孕周2SD,HL＜同孕周3SD,但胎儿伴有全身水肿.这14例胎儿长骨的生长速度均明显低于正常值,其中12例FL/AC＜0.16,另2例FL/AC分别为0.19和0.20,但FL或HL均明显小于均值,且伴有其他畸形.例15、16胎儿出生后随访1年,未见明显骨骼生长障碍.例17、18为成骨发育不全.(2)胎儿的围产结局及尸体检查:18例胎儿中8例女性,10例男性.其中1例于妊娠39周出生,为低出生体质量儿,体质量＜同孕周第三百分位数(3%th),其余胎儿出生体质量均无异常.18例肢骨发育异常病例均行染色体检查,其中羊水穿刺9例,脐带穿刺7例,2例出生后留取脐带血查新生儿染色体,染色体核型均未见异常.尸体检查16例.14例为软骨发育不全或软骨发育低下.镜下所见包括骨端增大,镜下管状骨软骨细胞增生,核大、深染,毛细血管增生,呈不规则长入软骨内.骨骺软骨细胞增生,骨化延迟.2例成骨发育不全,镜下可见干骺端增宽,骨小梁组织稀少.2例活产新生儿,其中1例为低出生体质量儿,随访至1岁,其四肢和身高在正常范围之内.结论 诊断软骨发育异常胎儿,不应仅依据股骨或肱骨长度显著短缩,且应动态观察长骨增长速度,计算FL/AC等综合进行判断.成骨发育不全胎儿,需通过X线,发现宫内骨折来判断.

Prenatal diagnose of abnormalities of fetal limb bone

Objective To discuss the prenatal diagnosis of abnormalities of fetal limb bone.Methods We selected 18 cases which long bone of fetus less than 2SD of average volume of gestational weeks or long bone changed into angle or other fetus's abnormalities by first B-mode ultrasonic. All above cases was delivered at Capital Medical University of Obstetric and Gynecological Hospital during Jan. 2006 to Dec. 2009. We B-mode ultrasonic was used to measure fetus's biparietal diameter (BPD) ,femur length (FL) ,abdominal circumference(AC) ,head circumference(HC) ,humerus length (HL) ,amniotic fluid index (AFI) and structures of organ and calculated FL/AC, growth speed of long bone. The standard of achondroplasia is that FL and HL are less than 4SD of average of gestational weeks or FL/AC less than 0. 16. The standard of Osteogenesis Imperfecta is fetal long bone of fetus shows short and thick, curves into angle, fracture in uterus by X-ray, or skull shows thin or sink by X-ray. Results (1) By B-mode ultrasonic and X-ray exam of all 18 cases: 7 cases shows that HC ＞2SD, 10 cases shows too much amniotic fluid, 12 cases shows AFI ＞ 18.0, 9 cases shows abnormalities of narrow cavitas thoracis, disordered vertebral column, or unusual architecture of heart. For cases 1 to 14 are achondroplasia, among which,11 cases are FL＜4SD and HL＜4SD, 2 cases are FL ＜3SD and HL ＜4SD, 1 case is not only FL ＜2SD and HL ＜3SD but also hydroncus all over the body of fetus. The growth velocity of long bone of fetus in all the 14 cases is more slowly than the normal rate. For all the above 14 cases, 12 cases FL/AC ＜0. 16, 1 case FL/AC =0. 19, 1 case FL/AC =0. 20. The length of femur or humerus is shorter than the normal rate and have other abnormalities the above last two cases. For case 15 and 16, they don't show any abnormalities of bone growth though one year's follow up studying. For case 17 and 18, they are osteogenesis imperfecta. (2) The result of fetal perinatal period fate and autopsy: there are 8 female and 10 male in all the 18 cases. One case is labored after 39 weeks pregnancy, and it is low birth weight infant, weight ＜3%th. All the other cases are normally birth weight infant. All the 18 cases of abnormalities of fetal limb bone are examined by chromosomes check, among which, 9 cases are amniocentesis, 7 cases are cordocentesis,2 cases are checked chromosomes by fetus cord blood, all the caryotype are normal. In the 16 autopsy cases,14 cases are achondroplasia or hypochondroplasis. It can be seen amplifying extremities, hyperplasia chondrocytes of tubiform born, karyomegaly, anachromasis, hyperplasia capillaries though microscope and grow up into cartilage irregularly. Also can be seen hyperplasia chondrocytes of epiphyses, delaying osteosis.2 cases are osteogenesis imperfecta. It can be seen broadening of metaphyses, exility of bone trabeculae. For the other two cases which the fetus is alive, we do the follow up studying to their one year old one of them is low birth weight new born, their limb and height are all normal. Conclusions To diagnose fetal Achondroplasia, it is not only based on the significantly shorter of femur or humerus length but also based on the dynamics observing the long bone growth velocity and calculating FL/AC. For osteogenesis imperfecta fetus, it should be diagnosed by fractures in uterus though X-ray.