Understanding How Your Baby's Heart Develops in the Womb

When you’re expecting, nothing matters more than hearing that tiny heartbeat. And because many congenital heart defects start early on, knowing how the heart forms and how fetal echocardiogram works can offer insight and a path toward timely care.

During pregnancy, one of the most important milestones is the development of your baby’s heart, the organ that will sustain them for a lifetime. The heart begins forming just weeks after conception, and it continues to grow and change throughout pregnancy, making this process both fascinating and delicate.

Understanding how the fetal heart develops can help expectant parents feel more connected to their baby’s growth. But it’s normal to have questions, especially if any concerns, like congenital heart disease, arise.

Devyani Chowdhury, MD, MHA, and our team at Cardiology Care for Children are here for you. We provide fetal echocardiograms in Lancaster, Mifflinburg, and Strasburg, Pennsylvania, and Topeka, Indiana, and we’re ready to help answer your questions.

How your unborn baby’s heart develops

Around week 3-4 after fertilization, cells begin forming two tubes that fuse into a primitive heart tube. This tube then begins looping and partitioning into future chambers — atria and ventricles — as well as forming septa (walls) and valves to direct blood flow properly. Even at this early stage, your baby’s heart is already pumping blood.

Over the next several weeks, the structure of your baby’s heart grows increasingly complex. The outflow tracts form, which lead to the pulmonary artery and aorta. The mitral and tricuspid valves develop, along with shunts that are critical for fetal circulation.

By the end of your first trimester, most of the major structural elements of your baby’s heart are in place. However, growth, maturation, and changes in blood flow continue throughout your pregnancy.

Because this process is so intricate, there are many ways things might not form exactly as expected — and these are congenital heart defects (CHD). CHDs may involve holes between chambers (septal defects), abnormal valves, abnormal connections of vessels, or other structural issues.

And when heart development doesn’t go as expected, early detection matters. Identifying CHDs as early as possible dramatically improves outcomes, because many congenital defects can be monitored, treated, or surgically corrected with better results earlier than later.

The role of fetal echocardiogram in CHDs

Fetal echocardiography is a specialized ultrasound we perform during pregnancy to evaluate your baby’s heart’s structure and function in the womb. It gives detailed information about the chambers, valves, major vessels, and blood flow, and we may recommend it if you have:

A family history of congenital heart disease
Maternal conditions that increase risk of CHDs, like certain illnesses or infections
Abnormal findings on a regular prenatal ultrasound, like unusual heart rhythm or suspected structural issue

With fetal echocardiogram, Dr. Chowdhury can identify issues early, often within the mid-to-late second trimester. This allows for planning, like deciding if you might need to deliver at a specialized center and preparing for interventions soon after birth if needed.

Dr. Chowdhury and our team work closely with obstetricians and ultrasound specialists to interpret fetal echo findings. Once a congenital heart condition is identified (or suspected), we work with you to develop a full care plan, which may include:

Continued monitoring with more frequent ultrasounds
Planning for delivery in a hospital with pediatric cardiac care available
Post-birth evaluation and imaging, possibly surgery or catheter-based treatments depending on the defect

These coordinated efforts ensure that both mom and baby are as safe as possible and that treatment begins promptly if needed. With early insight from tools like fetal echocardiogram, congenital heart disease care becomes not just about reacting, but about planning, collaborating, and optimizing outcomes.

Understanding how your baby’s heart develops in the womb can help you feel more informed and empowered, and we’re here to help answer all your questions. Learn more about your options and book a consultation at Cardiology Care for Children today.