Am J Perinatol 2024; 41(06): 771-777
DOI: 10.1055/s-0042-1749138
Original Article

Impact of a Potential 20-Week Abortion Ban on Likelihood of Completing Required Views in Second-Trimester Fetal Anatomy Ultrasound

Andrea Henkel*
1   Division of Family Planning Services and Research, Department of Obstetrics and Gynecology, Stanford University, Stanford, California
Isabel Beshar*
1   Division of Family Planning Services and Research, Department of Obstetrics and Gynecology, Stanford University, Stanford, California
Erica P. Cahill
1   Division of Family Planning Services and Research, Department of Obstetrics and Gynecology, Stanford University, Stanford, California
Yair J. Blumenfeld
2   Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, Stanford University, Stanford, California
Jane Chueh
2   Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, Stanford University, Stanford, California
Kate A. Shaw
1   Division of Family Planning Services and Research, Department of Obstetrics and Gynecology, Stanford University, Stanford, California
› Author Affiliations
Funding This research was supported through the Stanford School of Medicine MedScholars Fund.


Objective The aim of this study was to quantify the likelihood of assessing all mandated fetal views during the second-trimester anatomy ultrasound prior to the proposed federal 20-week abortion ban.

Study Design Retrospective cohort study of a random sample of 1,983 patients undergoing anatomy ultrasound in 2017 at a tertiary referral center. The difference in proportion of incomplete anatomic surveys prior compared with after 20-week gestation was analyzed using X 2 and adjusted logistic regression; difference in mean days elapsed from anomaly diagnosis to termination tested using t-tests and survival analysis.

Results Incomplete views were more likely with initial ultrasound before 20 weeks (adjusted relative risk: 1.70; 95% confidence interval: 1.50–1.94); 43.5% versus 26.1% were incomplete before and after 20 weeks, respectively. Fetal structural anomalies were identified in 6.4% (n = 127/1,983) scans, with 38.0% (n = 49) identified at follow-up after initial scan was incomplete. 22.8% (n = 29) with an anomaly terminated.

Conclusion A complete assessment of fetal views during an anatomy ultrasound prior to 20-week gestation is often not technically feasible. Legislation limiting abortion to this gestational age would greatly impact patient's ability to make informed choices about their pregnancies.

Key Points

  • It is often not technically possible to complete anatomy ultrasound prior to 20-week gestation.

  • Often, anomalies are missed during early, incomplete anatomy ultrasounds.

  • After the diagnosis of a structural anomaly, one in five chose to terminate the pregnancy.


Presented at the National Abortion Federation (NAF) Annual Conference in Chicago, Illinois (May 2019) and the American College of Obstetricians and Gynecologists (ACOG) Annual Clinical Meeting in Nashville, Tennessee (May 2019).

* These authors contributed equally to this work.

Publication History

Received: 14 October 2020

Accepted: 18 February 2022

Article published online:
16 May 2022

© 2022. Thieme. All rights reserved.

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