Safety of ultrasonography in pregnancy: WHO systematic review of the literature and meta-analysis.

Objective: In the context of the planned International Society of Ultrasound in Obstetrics and Gynecology-World Health Organization multicenter study for the development of fetal growth standards for international application, we conducted a systematic review and meta-analysis to evaluate the safety of human exposure to ultrasonography in pregnancy.
Methods: A systematic search of electronic databases, reference lists and unpublished literature was conducted for trials and observational studies that assessed short- and long-term effects of exposure to ultrasonography, involving women and their fetuses exposed to ultrasonography, using B-mode or Doppler sonography during any period of pregnancy, for any number of times. The outcome measures were: (1) adverse maternal outcome; (2) adverse perinatal outcome; (3) abnormal childhood growth and neurological development; (4) non-right handedness; (5) childhood malignancy; and (6) intellectual performance and mental disease.
Results: The electronic search identified 6716 citations, and 19 were identified from secondary sources. A total of 61 publications reporting data from 41 different studies were included: 16 controlled trials, 13 cohort and 12 case-control studies. Ultrasonography in pregnancy was not associated with adverse maternal or perinatal outcome, impaired physical or neurological development, increased risk for malignancy in childhood, subnormal intellectual performance or mental diseases. According to the available clinical trials, there was a weak association between exposure to ultrasonography and non-right handedness in boys (odds ratio 1.26; 95% CI, 1.03-1.54).
Conclusion: According to the available evidence, exposure to diagnostic ultrasonography during pregnancy appears to be safe.