From "Efficient Prenatal Care: Fewer Visits, Fewer Sonograms." Effective Clinical Practice, May/June1999.
Table 2. Outcomes for No Ultrasound vs. Routine Ultrasonography*
|*ARI = absolute risk increase (e.g., use fewer visits) to benefit one person; NNT (Benefits) = number needed to treat to benefit one person; NNT (Harm) = number needed to treat to harm one person; RRI = relative risk increase (from fewer prenatal visits). Note that for the outcomes presented here, the 95% CI includes the possibility of harm or benefit and thus passes through infinity.|