The biology behind fetal lung growth

Educational, not medical advice. If you have an urgent concern, call your physician or 911.

Module 2 — Understanding FETO · Episode 8

Lungs grow by being stretched

Before birth, the lungs are filled with fluid, not air, and they grow in part by being gently stretched. The fluid the lungs produce, and the breathing-like motions a fetus makes, create mechanical forces that tell lung cells to divide, mature, and build the tiny air sacs where breathing will later happen.

Why this explains FETO

This is the principle FETO uses. By holding lung fluid in, the balloon increases that stretch signal and pushes the lungs to grow. In other words, FETO is not adding anything biological; it is amplifying a natural growth cue.

What the lab studies

Our research asks how lung cells actually sense that stretch and turn it into growth. A central player is a stretch-sensitive protein called PIEZO1, which helps convert physical force into the internal signals (involving calcium and a regulator called YAP) that guide how lung cells develop. Understanding this pathway could help explain why FETO helps some babies more than others, and could point toward future therapies that work with the same biology.

Back to Module 2 · Related: the research module