[Impact and limitations of ultrasound examination immediately before delivery--a prospective evaluation with 1127 pregnant women].

OBJECTIVE

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.

PATIENTS AND METHODS

Within 1 year we examined 1,127 consecutive pregnant women with 1,151 foetuses on the basis of a routine ultrasound examination.

RESULTS

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.

CONCLUSION

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.