First trimester fetal heart evaluation: A pictorial essay

Abstract

Classically fetal heart evaluation is mandatory in the second trimester of pregnancy. Recent data suggest that the diagnosis of congenital heart disease is feasible in the first trimester (FT) of pregnancy, especially for trained examiners. In this pictorial essay we aim to illustrate in detail the particularity of the FT heart evaluation: the specific ultrasound techniques including practical tips for the basic and extended first trimester fetal heart evaluation protocol. The diagnosis is possible by the use of a variety of ultrasound techniques (B mode, CFM, Bidirectional Doppler, STIC, TUI) using the transabdominal/transvaginal probes. An abnormal FT heart scan requires second trimester reassessment. Unfortunately, not all cardiac disease can be potentially diagnosed in the first trimester. Based on their own experience the authors recommend that heart examination in the FT should be attempted in all fetuses, even in low risk pregnancies, using at least the basic Doppler examination protocol.