Kranz C, Hitschold T
Frauenklinik, Perinatalzentrum, Brustzentrum am Klinikum Worms.
Z Geburtshilfe Neonatol. 2011 Apr;215(2):69-76. doi: 10.1055/s-0031-1273716. Epub 2011 May 3.
Birth weight is an important confounder to foetal morbidity and mortality. There is controversy about the necessity of ultrasound examinations immediately before delivery. As only few studies on unselected populations have been published, some recommendations exist in the context with shoulder dystocia, water delivery and breech delivery.
Within 1 year we examined 1,127 consecutive pregnant women with 1,151 foetuses on the basis of a routine ultrasound examination.
A total of 92% of all women were examined by ultrasound. Nearly 80% of these examinations took place within 72 h prior to delivery. The accuracy of foetal weight estimate (±10% variance) was 72% and did not gain due to the grade of the examiner's experience. There was no difference between routine and complicated conditions such as oligohydramnios, obesity, contractions. Also week of gestation had no influence. Macrosomic foetuses were underestimated in more than 50%. In 85% of pregnancies there was at least one risk factor and rate of Cesarean sections was due to this fact. Overall there were 8.5% macrosomic foetuses and 15.1% were SGA. 16.5% of the women were obese with BMI >30.
Foetal weight estimation by means of ultrasound is easy and fast and does not need a high level of experience. There is no negative influence on accuracy of weight estimate by examination conditions and week of gestation. Ultrasound examinations also give information about foetal position, placental localisation and amount of amniotic fluid. Together with maternal risk factors, the prospective planning and leading of birth requires ultrasound biometry prior to delivery.
出生体重是胎儿发病和死亡的一个重要混杂因素。分娩前立即进行超声检查的必要性存在争议。由于仅有少数关于未选择人群的研究发表，因此在肩难产、水中分娩和臀位分娩方面存在一些建议。
在1年时间内，我们基于常规超声检查对1127名连续孕妇及其1151名胎儿进行了检查。
共有92%的孕妇接受了超声检查。其中近80%的检查在分娩前72小时内进行。胎儿体重估计的准确性（±10%差异）为72%，且并未因检查者的经验水平而提高。在羊水过少、肥胖、宫缩等常规和复杂情况下，准确性并无差异。孕周也没有影响。超过50%的巨大胎儿被低估。在85%的妊娠中至少存在一个风险因素，剖宫产率也因此受到影响。总体而言，巨大胎儿的比例为8.5%，小于胎龄儿的比例为15.1%。16.5%的女性肥胖，BMI>30。
通过超声估计胎儿体重简便快捷，且不需要高水平的经验。检查条件和孕周对体重估计的准确性没有负面影响。超声检查还能提供胎儿位置、胎盘定位和羊水量等信息。结合母亲的风险因素，分娩的前瞻性规划和指导需要在分娩前进行超声生物测量。
