Routine obstetric ultrasound examinations in South Africa: cost and effect on perinatal outcome--a prospective randomised controlled trial.
OBJECTIVE: To compare routine midtrimester with selective obstetric ultrasonography concerning the Health Service cost and the effect on perinatal outcome. DESIGN: A randomised controlled trial. SETTING: Urban area served by Tygerberg Hospital, a tertiary referral centre in South Africa. PARTICIPANTS: Pregnant patients without risk factors for congenital anomalies referred for ultrasonography between 18 and 24 weeks of gestation. INTERVENTION: Between 18 and 24 weeks, a level one ultrasound examination was performed on study patients only. Except for the routine scan, both groups received the same antenatal care and could be referred later for additional scans as judged by their clinicians. MAIN OUTCOME MEASURES: Overall adverse perinatal outcome and use of antenatal and neonatal services. RESULTS: The groups did not differ significantly in their use of antenatal and neonatal services except for a greater number of ultrasound scans in the study group. More suspected postdate pregnancies occurred in control patients, as well as more amniocenteses for confirmation of lung maturity. More babies of low birthweight were born in the study group. The incidence of overall or major adverse perinatal outcome was comparable. Routine ultrasonography was accompanied by a considerable increase in costs. CONCLUSION: Selective use of obstetric ultrasonography did not increase the use of antenatal and neonatal services. Not routinely performing ultrasonography has led to considerable Health Service savings without increasing the risk for adverse perinatal outcome. It saved 75% of selected patients a referral to an ultrasound unit. Specific problems related to inaccurate gestational age determination need to be addressed.