ANTENATAL SCREENING FOR CARRIERS OF CYSTIC-FIBROSIS - RANDOMIZED TRIAL OF STEPWISE V COUPLE SCREENING

Objective-To perform a rigorous comparative evaluation of stepwise and couple approaches to antenatal carrier screening for cystic fibrosis. Design-Pragmatic randomised trial. Setting-Hospital antenatal clinic serving a regional population. Subjects-2002 women (couples) attending for booking antenatal visit at less than 17 weeks' gestation with no family history of cystic fibrosis. Interventions-Offering counselling and carrier testing for cystic fibrosis, either to women in the first instance (stepwise) or to couples (couple screening). Main outcome mea sures-Uptake rates; anxiety; knowledge of cystic fibrosis and carrier status (both partners); attitudes to health, pregnancy, the baby, and screening (both partners); and uptake of carrier testing by relatives. Results-Uptake of screening was the same for both approaches (90%). A fter delivery most women remembered test results and their meaning, bu t 53/253 (21%) of those with negative results of couple testing had fo rgotten that repeat testing would be advisable if they had a pregnancy with a new partner. With stepwise screening women identified as carri ers had high levels of anxiety when results were received (mean anxiet y score 52.3). This dissipated with a reassuring partner's result (car riers' mean anxiety score 36.1) to levels similar to those receiving n egative results from couple screening. Of those receiving negative res ults, women who had stepwise screening were significantly less anxious than those who had couple screening (mean score with result 32.1 v 35 .4, 95% confidence interval for difference -4.7 to -2.1). Conclusions- Couple screening allows carriers to avoid transient high levels of anx iety, but is associated with more anxiety and false reassurance among most screenees who will test negative. Stepwise screening gives carrie rs and their relatives genetic information and is, in our opinion, the better method.