Materials and Methods: In this retrospective study, we examined the difference between natural and assisted-reproductive technology (ART) pregnancies in 2252 mothers from January 2011 to October 2019. In both groups, the first trimester screening parameters including NT, free beta-human chorionic gonadotropin (β-hCG), and PAPP-A were measured.

Results: According to the results of the present study, BMI was higher in the group that became pregnant by IVF compared to the normal pregnancy group (P < 0.001). Additionally, in patients using IVF, the history of maternal disease was less frequent compared to the other group (P = 0.003). Most cases of twin fetuses, dichorionic twin pregnancy, and fetal abnormality were seen in the IVF group. Although the β-hCG and free PAPP-A levels were high in the IVF group, no significant difference was observed. The group with spontaneous pregnancy had a higher penetration rate of nuchal translucency <95th percentile compared to the IVF group (P < 0.001). The results of comparing the first trimester test showed that in the IVF group, 81.3% of patients were at low risk and 6.6% were at high risk, while in the normal pregnancy group, 78.9% of patients were at low risk and 7.0% of them were at low risk, indicating that the difference was not significant.

Conclusions: Overall, although the risk of aneuploidy in IVF pregnancies was not higher compared to normal pregnancies, in IVF pregnancies, NI is associated with a high risk of fetal abnormalities. Therefore, NT sonography can help to diagnose fetal anomalies especially aneuploidy