Assessment of obstetric ultrasonography for the control of normal pregnancies in primary care

Aymerich M, Almazan C, Jovell AJ
Record ID 31998008952
Catalan, English, Spanish
Authors' objectives:

To study, by means of a systematic review of the scientific evidence, the innocuity and effectiveness of routine compared to selective ultrasonography and to review a selection of the clinical practice guidelines and protocols designed to control pregnancies for the whole population of pregnant women, and to describe the possible implications of ultrasonography adoption in primary care, by means of both an economic and health services provision points of view.

Authors' results and conclusions: Compared to selective, routine ultrasonography is harmless and, regarding its effectiveness, it does not improve perinatal mortality, but it does provide a better measurement of gestational age, and it also detects multiple pregnancies and unsuspected congenital malformations earlier. The diagnostic accuracy in the detection of congenital malformations in the 'general' population of pregnant women has only been analysed in specialized obstetrics centres. The value of the resulting specificity of each of this four studies is high (99.9%), while the range of the sensitivity values is quite broad in the different studies, from 20% to 96%. According to a meta-analysis of diagnostic tests, the diagnostic accuracy of each of the different ultrasonographic markers for the prenatal detection of the Down syndrome - nuchal fold, length of femur or the combination of both, has global sensitivity values ranging from 32% (length of femur at second trimester of pregnancy) to 65% (nuchal fold at first trimester), and global specificity values ranging from 92% (length of femur at second trimester) and 99% (nuchal fold at second trimester). The review of the clinical practice guidelines and protocols regarding the clinical applicability of ultrasonography showed that, while some of them recommended carrying out three ultrasound tests during the pregnancy, others doubt this strategy for the ultrasonographic control of the pregnancy, since they consider that there is not enough scientific evidence showing the benefit of ultrasonography in decreasing perinatal mortality and morbidity. Thus, the number of ultrasonographies and its indication is not determined by scientific criteria.
Authors' recommendations: The introduction of ultrasonography for the control of normal pregnancies in primary care should be carried out in experimental study conditions, to generate the necessary scientific evidence to assess the effectiveness and diagnostic accuracy of obstetric ultrasonography at this level of health care. Although routine ultrasonography has shown to be harmless, the safety of this screening technology regarding the existence of false positives and false negatives should be taken into consideration. A false negative result might lead to a lack of medical care to a fetus actually in need of it. On the other hand, a false positive result might produce, besides the unwanted psychologic pressure upon the parents, exposure to the consequences of the invasiveness the prenatal diagnostic confirmation test, as well as an additional cost. The adoption of ultrasonography in primary care cannot be recommended. The adoption of this technology should be based on assessment criteria of effectiveness, safety, and diagnostic precision, and guaranteeing its health care quality - these criteria are still to be determined - and also taking into account the scientific evidence, the professional's accreditation the minimum volume of tests; the number of ultrasonographies economically affordable; the equity criteria; the priority of selective ultrasonography, and organizational criteria.
Authors' methods: Systematic review
Project Status: Completed
Year Published: 1997
English language abstract: An English language summary is available
Publication Type: Not Assigned
Country: Spain
MeSH Terms
  • Down Syndrome
  • Mass Screening
  • Prenatal Diagnosis
  • Ultrasonography
Organisation Name: Agencia de Qualitat i Avaluacio Sanitries de Catalunya
Contact Address: Antoni Parada, CAHTA, Roc Boronat, 81-95 (2nd floor), 08005 Barcelona, Spain, Tel. +34 935 513 928, Fax: +34 935 517 510
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Copyright: Catalan Agency for Health Technology Assessment and Research
This is a bibliographic record of a published health technology assessment from a member of INAHTA or other HTA producer. No evaluation of the quality of this assessment has been made for the HTA database.