Utility of Non-Invasive Prenatal Test (NIPT) as a Screening Tool for Fetal Aneuploidy in a Family Medicine Setting in Saudi Arabia.

BACKGROUND

Chromosome aneuploidy is the most common type of fetal chromosome disorder. This study aims to determine the utility of Non-Invasive Prenatal Test (NIPT) in detecting chromosomal aneuploidy among high-risk Saudi pregnant women.

METHODS

This retrospective cohort study examined the charts of all pregnant women who attended the antenatal clinics of the Ministry of National Guard-Health Affairs, King Abdulaziz Medical City, Riyadh, Saudi Arabia, from January 2012 to July 2022, and underwent NIPT testing. Data were collected on obstetric history, NIPT testing, confirmatory invasive testing (amniocentesis/chorionic villus sampling, "CVS"), and pregnancy outcomes.

RESULTS

Of all the studied pregnant women (n=958), 46 women had positive NIPT (40 trisomy 21, 4 trisomy 18, and 2 trisomy 13), giving an incidence of 4.8% (95% CI 3.6-6.3%), and a positive predictive value of 100%. Pregnant women >40 years of age showed an 8-fold increased risk of any aneuploidy compared to younger women <30 years of age (OR=8.07, 95% CI 2.35-27.73). Those with fetal ultrasound (US) results of more than 30 weeks of gestation had a 2-fold increased risk compared to those with results of less than 20 weeks of gestation (OR = 2.15, 95% CI 0.93-4.98), and those with abnormal US fetal anatomy had an 88-fold increased risk compared to those with normal US (OR=88.33, 95% CI 36.10-216.16). Both advanced maternal age (OR = 1.14, p < 0.001) and abnormal ultrasound fetal anatomy (OR = 92.45, p < 0.001) were significant predictors of chromosomal aneuploidy. None of the counseled women opted for pregnancy termination.

CONCLUSION

The study's finding is a powerful clinical message that strengthens confidence in positive NIPT results at similar referral centers and provides a strong local evidence base for counseling high-risk Saudi women about the implications of positive NIPT results. It provides confirmation that local risk factors align with global patterns.