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Evidence summaries

Ultrasound for Fetal Assessment in Early Pregnancy

Ultrasound in early pregnancy appears to be effective for early detection of multiple pregnancies and for improved gestational dating. Level of evidence: "B"

Comment: The quality of evidence is downgraded by study quality (lack of blinding and some other shortcomings).

A Cochrane review [Abstract] 2 included 13 studies with a total of 85 265 subjects. First trimester routine ultrasound reduced short-term maternal anxiety (RR 0.80, 95% CI 0.65 to 0.99; 1 trial, n=634) compared with selective ultrasound, Second trimester scans reduced induction of labour for post-maturity (RR 0.48, 95% CI 0.31 to 0.73; 6 trials, n=24 174), improved detection of multiple pregnancy (RR 0.05, 95% CI 0.02 to 0.16; 5 trials, n=274), increased detection of major fetal abnormality before 24 weeks (RR 3.45, 95% CI 1.67 to 7.12; 2 trials, n=387) and increased the number of women terminating pregnancy for major anomaly (RR 2.36, 95% CI 1.13 to 4.93; 4 trials, n=26 893).

A Cochrane review [Abstract] 1 included 11 studies with a total of 37 505 subjects. Routine (revealed) vs selective (concealed) ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks' gestation (RR 0.07, 95% CI 0.03 to 0.17; 7 trials, n=295). Routine scan is associated with a reduction in inductions of labour for post-term pregnancy (RR 0.59, 95% CI 0.42 to 0.83; 8 trials, n= 25516). Routine scans do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies. Long-term follow up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children's physical or cognitive development.

    References

    • Whitworth M, Bricker L, Mullan C. Ultrasound for fetal assessment in early pregnancy. Cochrane Database Syst Rev 2015;(7):CD007058. [PubMed]
    • Kaelin Agten A, Xia J, Servante JA et al. Routine ultrasound for fetal assessment before 24 weeks' gestation. Cochrane Database Syst Rev 2021;(8):CD014698. [PubMed]

Primary/Secondary Keywords