Objectives: A recent randomized controlled trial of first-trimester anatomy ultrasound in obese women found some advantages to using this technique in this population, but some aspects of feasibility were not clear, such as whether first-trimester ultrasound can be brought outside of a research setting. The learning curve for first-trimester anatomy has been described in the general population, but a learning curve has not been described for this technique in obese patients. This study sought to describe a learning curve for first-trimester anatomy ultrasounds in obese patients with an operator familiar with the basics of first-trimester imaging. Design: This was a secondary analysis of the EASE-O pilot randomized controlled trial (NCT04639973), which recruited 128 women with a BMI ≥35 kg/m2 and randomized them into two groups based on the timing of the first evaluation of fetal anatomy, to compare the completion rate of first- and second-trimester anatomy ultrasound. Participants: Pregnant women with a BMI ≥35 kg/m2 participated in the study. Setting: Between January 2021 and February 2022, the study was conducted at maternal-fetal medicine clinics in Houston, TX, USA. Methods: This secondary analysis evaluated data on the completion rate of first-trimester scans from the parent trial. Scans were grouped into bin sizes of 3, and prop_model for R version 4.2.0 for Windows was used to generate a learning curve across the first 60 scans. Results: The parent study included 60 scans performed by one imager who had previously only done first-trimester scans in lean patients for limited anatomy. The probability of a complete scan increased over 60 scans from 0.38 to 0.69; 29 scans were required to reach the final probability, after which only marginal improvement followed. Limitations: The major limitation is the inclusion of only one operator for this curve. Conclusions: For an ultrasound operator with basic familiarity in first-trimester imaging, approximately 30 scans are needed to acquire a completion rate of 70% for detailed first-trimester anatomy in women with BMI ≥35 kg/m2. This can be used in education and training programs focused on imaging in the first trimester.

1.
International Society of Ultrasound in Obstetrics and Gynecology
,
Bilardo
CM
,
Chaoui
R
,
Hyett
JA
,
Kagan
KO
,
Karim
JN
, et al
.
ISUOG Practice Guidelines (updated): Performance of 11–14‐week ultrasound scan
.
Ultrasound Obstet Gynecol
.
2023
;
61
(
1
):
127
43
. .
2.
Buskmiller
C
,
Fishel Bartal
M
,
Bonilla
M
,
Denham
C
,
Nguyen
R
,
Sibai
B
, et al
.
First trimester anatomy ultrasound for patients with obesity: a randomized controlled trial
.
Am J Obstet Gynecol
.
2023
;
5
(
11
):
101143
. Epub ahead of print.
3.
Taipale
P
,
Ammälä
M
,
Salonen
R
,
Hiilesmaa
V
.
Learning curve in ultrasonographic screening for selected fetal structural anomalies in early pregnancy
.
Obstet Gynecol
.
2003
;
101
(
2
):
273
8
.
4.
Bardi
F
,
Bakker
M
,
Elvan-Taşpınar
A
,
Kenkhuis
MJA
,
Fridrichs
J
,
Bakker
MK
, et al
.
Organ-specific learning curves of sonographers performing first-trimester anatomical screening and impact of score-based evaluation on ultrasound image quality
.
PLoS One
.
2023
;
18
(
2
):
e0279770
.
5.
Abu-Rustum
RS
,
Ziade
MF
,
Abu-Rustum
SE
.
Learning curve and factors influencing the feasibility of performing fetal echocardiography at the time of the first-trimester scan
.
J Ultrasound Med
.
2011
;
30
(
5
):
695
700
.
6.
AIUM practice parameter for the performance of detailed diagnostic obstetric ultrasound examinations between 12 Weeks 0 Days and 13 Weeks 6 days
.
J Ultrasound Med
.
2021
;
40
(
5
):
E1
E16
.
7.
Sripilaipong
S
,
Panburana
P
,
Wattanayingcharoenchai
R
,
Tangshewinsirikul
C
.
Feasibility and learning curve of performing first trimester fetal anatomy screening among operators with varying experience using the protocol of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)
.
J Matern Fetal Neonatal Med
.
2022
;
35
(
25
):
8691
7
.
8.
Harper
LM
,
Wood
SL
,
Jenkins
SM
,
Owen
J
,
Biggio
JR
.
The performance of first-trimester anatomy scan: a decision analysis
.
Am J Perinatol
.
2016
;
33
(
10
):
957
65
.
You do not currently have access to this content.