Detailed fetal anatomy assessment in the first trimester at 11, 12 and 13 weeks of gestation

Abstract

Evaluation of most part of the fetal anatomical structures is feasible with high accuracy in the first trimester. Visualization of the majority of the targeted fetal organs improves from 11 to 13 weeks.

Early Detection of Structural Anomalies in a Primary Care Setting in the Netherlands

“…In line with previous studies [16,17], this study indicates that training and education play a major role in the successful completion of a detailed US examination and that the optimal time for a first-trimester scan is 12-13 weeks [18,19], when most fetal organs are sufficiently developed [14,20,21], their visualization can be complete in 86% of cases [22], the majority of spontaneous losses have already occurred (from 81 at 11 weeks to 13 at 13 weeks) [23], and only 3% may still occur thereafter [24]. In a previous prospective study by our group, we showed that when sonographers are instructed to perform a survey of fetal anatomy at the early scan, the detection rate can increase to 45% [4].…”

‘Bat‐like’ choroid plexus and other sonographic features in trisomy 22 at the first trimester of pregnancy

“…5 Moreover, once a fetal abnormality has been diagnosed, the couple can opt for invasive genetic testing or ask for pregnancy termination. 1,6 Although a single case report cannot establish a casual association between 'bat-like' choroid plexus cysts and trisomy 22, our findings if confirmed by others would add this configuration of the choroid plexuses to the list of the sonographic markers for fetal chromosome anomalies.…”

“…During every first trimester scan, at our unit, the operator tries to analyze fetal morphology following a systematic visualization of anatomy using a transabdominal 2D probe (AB2‐7D), a 3D‐4D probe (RAB4‐8‐D), and a transvaginal one reaching 18.000 mHz (RIC6‐12‐D).…”

Early anatomy ultrasound in women at increased risk of fetal anomalies

“…These limitations can be circumvented by screening the fetus slightly later in pregnancy and by incorporating the use of high frequency transvaginal ultrasound, which improves visualization of fetal organs in early pregnancy . It is therefore not surprising that, when both of these approaches were combined in our study, anomaly detection rates were higher than those traditionally reported in the first trimester.…”

“…At this gestational age, most anatomical structures are fully formed and the fetus is sufficiently large to be comprehensively examined with conventional transabdominal ultrasound equipment . The use of higher frequency transvaginal ultrasound probes and improvements in software, however, allow for better visualization of anatomic detail at earlier gestational ages . This, in combination with the widespread implementation of first trimester screening programs for aneuploidy has led to an increase in ultrasound screening of the fetal anatomy as early as 11–14 weeks gestation.…”