From screening chromosomal anomalies to early diagnosis of fetal malformations

The aim of this review is to understand why and how to improve the detection rate of the fetal anomalies in the first trimester.

The role of the first trimester is evolving from aneuploid and basic anatomical screening to a necessary tool to identifying early fetal malformations. In the past 20 years, several studies were conducted to assess the detection rate of anomalies in the first trimester, and despite the improvement in the diagnoses of spina bifida and cleft lip, many anomalies detectable in the first trimester are still being diagnosed in the second trimester scan. Analyzing the factors that improve the detection rate can show the reason why, even in recent years, only 50% of the anomalies are diagnosed in the first trimester.

Thanks to the improvement in the ultrasound technology, the fetus can be thoroughly studied even in early gestation and it is, therefore, indispensable to increase the detection rate of the anomalies diagnosable from the first trimester. The sonographer's utmost attention should be applied to all pregnancies, not only in high-risk patients, and new protocols based on the mid trimester scan are needed to spread the concept of first trimester anatomical scan.