Ultrasound Imaging of Obese Pregnant Women

As the rate of obesity continues to increase worldwide (last reported by the CDC as 42.4% as of 2017–2018), it has become even more evident that there is a great need to improve fetal cardiac visualization in obese pregnant women. Less than 50% of morbidly obese women have successful fetal 4-chamber and outflow tract visualization, compared to almost 90% of nonobese women.

Obese women are also significantly more likely than normal-weight women to have children with a congenital heart disease, with an even higher risk in morbidly obese women, who give birth to children who have higher odds of having atrial septal defects, hypoplastic left heart syndrome, aortic stenosis, pulmonic stenosis, and tetralogy of Fallot.

And when obese pregnant women have reduced rates of complete anatomic surveys, lower detection rates, and increased risk of fetal anomalies due to less than perfect anatomy visualization, how do we improve the fetal cardiac visualization?

A team of researchers from Eastern Virginia Medical School looked into whether ultrasound (US) imaging in early gestation could help.

Amara Majeed, MD; Alfred Abuhamad, MD; Letty Romary, MD; and Elena Sinkovskaya, MD, PhD, performed a study in which all study participants (obese pregnant women) with a gestational age of 13 weeks to 15 weeks 6 days, underwent an US exam using a transvaginal or transabdominal approach and color Doppler US for fetal cardiac screening, which they defined as complete when all components of the 4-chamber, right ventricular outflow tract, left ventricular outflow tract, and 3-vessel views were clearly visualized. The participants also underwent a traditional transabdominal examination at 20 to 22 weeks, and if that exam was incomplete, underwent another 2 to 4 weeks later.

What they found was that the addition of early-gestation US to the 20- to 22-week US exam of obese pregnant women substantially improved the visualization of fetal cardiac anatomy. And for the women with a BMI of greater than 40 kg/m2, the cardiac screening completion rate was even higher (significantly so) for the early-gestation exam plus a traditional exam (90%) than for the traditional exam plus the second traditional exam (72.7%).

Adding an ultrasound exam at a gestation age of 13 weeks to 15 weeks 6 days substantially improved the visualization of fetal cardiac anatomy, particularly for the women with a BMI of greater than 40 kg/m2. Having complete or more complete anatomy screening can enable an earlier, accurate diagnosis.

To read more about this study, download the Journal of Ultrasound in Medicine article, “Can Ultrasound in Early Gestation Improve Visualization of Fetal Cardiac Structures in Obese Pregnant Women?”. Members of the American Institute of Ultrasound in Medicine can access it for free. Join today!

If you have any questions about the study, please ask in the comments; the authors of the article will be happy to respond.

See a Need; Fill a Need

The Increasing Demand for the Detailed Fetal Echocardiogram & Specialization of the Fetal Cardiac Sonographer

With congenital heart defects (CHDs) continuing to lead the pack of anomalies resulting in infant mortality (1) the need for detailed cardiac screening of the developing fetal heart remains a pertinent and valuable tool for obstetrical providers and their patients.

Fetal echocardiography was derived for the purpose of improving antenatal detection rates of fetal cardiac defects. Identification of these in utero can initiate referrals to perinatology, genetic counseling, and pediatric cardiologists where parents can gain further insight about the suspected anomaly, as well as consult about any recommendations and/or expected outcomes. Timely diagnosis can provide the opportunity for a planned delivery at a tertiary center that is properly equipped to provide any necessary support and/or intervention the afflicted newborn may require.

While the basic evaluation of the heart remains part of the fetal anatomical survey (2), obtaining even the standard cardiac views continues to be a challenge in many cases, as adequate views are dependent on many factors including fetal position, maternal body habitus, and sonographer experience.

In order to provide you a visual of why imaging a fetal heart can pose such a challenge for sonographers, keep in mind that the fetal heart is roughly the size of a quarter (3) at 20 weeks of gestational age, which happens to be the timeframe of when most detailed anatomical surveys are attempted. Even more impressive is the fact that the pulmonary veins, whose anomalous drainage can be fatal if undetected prior to delivery, are comparable in size to Jefferson’s nose on the nickel. It has been my experience, if you ask any sonographer performing obstetrical exams which organ is the most difficult to assess on the anatomical survey, the fetal heart likely sits somewhere near the top of their list.

However, the demand for fetal echocardiography is expanding as the understanding of congenital heart disease continues to identify specific populations that have an increased risk of having a fetus with a CHD. (4) This lengthy list of indications for the fetal echocardiogram has historically been divided up into 2 main categories: maternal risk factors and fetal risk factors. As the number of indications for the exam continues to grow larger, so does the need to have highly trained and competent OB sonographers who go on to become certified in fetal echocardiography.

I must also point out that it is a necessity for all sonographers performing anatomical surveys to sharpen their skills at obtaining fetal cardiac images as even with the established indications, congenital heart defects continue to be the most missed anomaly on the prenatal screening sonogram. (5) This is a great example of why continuing education in the sub-specialty of fetal echo, as well as standardized protocols and training, is so important for all of us. Increasing prenatal detection rates of CHDs is a community effort that we can all contribute towards.

The challenge of deepening one’s understanding of fetal cardiac anatomy/physiology, and becoming more proficient at obtaining the detailed fetal echo views, remains an intimidating next-step for many OB sonographers. However, I personally invite those sonographers to face this challenge head-on, understanding that with experience and time, you’ll feel more confident and capable of completing a detailed fetal heart study with every fetal echo you perform.

Fetal echocardiography is a prime example of how something can be both extremely challenging and yet incredibly fulfilling at the same time. Detection of even the smallest cardiac defect in utero can later prove to have made a significant impact on the neonatal management of the newborn and positively impact infant mortality rates in the cases of more severe cardiac lesions. You may ultimately become a key factor in ensuring that your patients get the postnatal care that they require and deserve.


(1) Maulik D, Nanda N, Vilchez G. A brief history of fetal echocardiography and its impact on the management of congenital heart disease. Echocardiography 2017; 34:1760–1767.

(2) Pellerito J, Bromley BS, et al. AIUM-ACR-ACOG-SMFM-SRU Practice parameters for the performance of standard diagnostic obstetric ultrasound examinations. J Ultrasound Med 2018; 9999:1–12.

(3) Drose JA. Scanning: indications and technique. Fetal Echocardiography. Philadelphia, PA: Saunders; 1998:15–16.

(4) Wesley L, Anton T, et al. AIUM Practice parameter for the performance of fetal echocardiography. J Ultrasound Med 2020; 39:E5–E16.

(5) Abuhamad A, Chaoui R. Guidelines for the sonographic screening and Echocardiogram of the fetal heart. A Practical Guide to Echocardiography: Normal and Abnormal Hearts. 3rd ed. Wolters Kluwer; 2015:13.

Jaime Taylor-Fujikawa, BS, RDMS, RDCS, is a perinatal sonographer/fetal echocardiographer at The Center for Genetics and Maternal Fetal Medicine in Springfield, Oregon. She is a graduate of The Seattle University Diagnostic Ultrasound Program, class of 2005. She is a wife and mother to two boys.

Interested in learning more about Obstetric Ultrasound? Check out the following posts from the Scan: