The 11–13+6 weeks scan

10 The 11–13+6 weeks scan Invasive diagnosis Amniocentesis There is only one randomized trial which compared the risks of amniocentesis to controls. In this study, 4,606 low-risk, healthy women, 25–34 years old, at 14–20 weeks of gestation, were randomly allocated to amniocentesis or ultrasound examination alone (Tabor et al 1986). ................
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