[Ultrasound screening in pregnancy: evidence and maternity care reality].
Since 1980 maternity care in Germany has included ultrasound screening. The aim of this review is (1) to assess the benefit of ultrasound screening on the basis of randomised, controlled trials in accordance with the criteria of evidence-based medicine, (2) to examine current screening practice and the quality of German maternity care in everyday clinical practice, and (3) to indicate priorities for further screening developments. We reviewed Cochrane reviews, health technology assessment reports and relevant individual studies. The three essential effects that may be achieved by ultrasound screening include: (1) earlier detection of multiple pregnancies, (2) better dating of pregnancy and reduction in induced labour by 40%, and (3) more frequent and earlier detection of foetal malformations including the option for an abortion. Yet, early detection does not increase the rate of successful pregnancies. The effects mentioned are only incompletely achieved with standard maternity care in Germany. For example, there is no evidence for an essential reduction of the frequency with which labour is induced. Detection rates in routine preventive care are markedly lower than described for trial conditions. Only multiple pregnancies can be identified more or less completely; detecting other target diagnoses remains unsatisfactory: placenta praevia 57% (without signs of bleeding 14%), postmaturity 46%, malformations 30-40% and intrauterine growth retardation 30%. Also, high rates of false positive findings can be observed that might lead to follow-up examinations and unnecessary treatment procedures. Quality of maternity screening is low and is not subjected to substantial quality assurance. We suggest the following priority measures: (1) to improve the quality of screening by modifying the previous three-step concept with the aim of promoting accessibility of highly qualified examiners for all pregnant women, (2) to strengthen quality assurance, (3) to assist the pregnant woman with her informed decision by offering independent and non-directional counselling concerning the advantages and disadvantages of screening and (4) to focus maternity care on effective interventions according to the criteria of evidence-based medicine.