At seven months of pregnancy (about 28 weeks), a fetus measures roughly 14 to 15 inches long from head to heel and weighs around 2.2 pounds (1,000 grams). That’s about the size of a large eggplant. While still small, a seven-month fetus has developed enough that survival outside the womb is possible, though the final weeks of pregnancy remain critical for brain and lung maturation.
Size and Weight at 28 Weeks
The 14- to 15-inch length of a seven-month fetus represents crown-to-heel measurement, meaning from the top of the head all the way to the bottom of the feet. Earlier in pregnancy, fetuses are measured crown to rump (head to bottom) because the legs are curled tightly, but by the third trimester the full length is used. At 2.2 pounds, the baby still has significant growing to do. Most of the weight gain happens in the final two to three months, when a fetus typically triples in size before birth.
Weight can vary quite a bit from one pregnancy to the next. Factors like genetics, placental health, and maternal nutrition all influence how large or small a fetus is at any given point. Your provider tracks growth through ultrasound measurements and fundal height, which is the distance from your pubic bone to the top of the uterus. At 28 weeks, that measurement should be close to 28 centimeters, give or take about 2 centimeters.
What a Seven-Month Fetus Looks Like
By this stage, the fetus looks much more like a newborn than the earlier, translucent figure of the second trimester. The skin is still thin and somewhat wrinkled, but fat is starting to accumulate underneath, gradually smoothing things out. A fine layer of soft hair called lanugo still covers parts of the body. This hair develops between 16 and 20 weeks and serves a specific purpose: it holds a waxy coating called vernix against the skin, which protects the fetus from the amniotic fluid that would otherwise irritate delicate skin. Lanugo typically falls off during the last eight weeks of pregnancy, so a seven-month fetus still has most of it.
The eyelids, which were fused shut earlier in development, can now open and close. Fingernails and toenails have formed. The body proportions are closer to what you’d see at birth, though the head is still relatively large compared to the rest of the body.
Brain Development at Seven Months
The third trimester is a period of rapid brain growth, and at seven months that acceleration is well underway. The cerebral cortex, the outer layer of the brain responsible for voluntary movement, memory, and awareness, becomes significantly more active during this time. The brain’s surface, which was relatively smooth earlier, begins folding into the grooves and ridges that characterize a mature brain, dramatically increasing the available surface area for neural connections.
One of the most striking signs of brain maturity at this stage is habituation. This means the fetus can recognize a repeated stimulus, like a loud noise, and stop reacting to it once the brain determines it’s not a threat. That’s a basic but real form of learning. Fetuses at this stage also begin responding to light filtering through the uterine wall and can distinguish familiar sounds. Research on newborns suggests that by late pregnancy, babies have already started forming preferences for their mother’s voice and the rhythmic patterns of her speech.
Lung Maturity and Breathing Readiness
Lungs are one of the last organs to fully mature, and at seven months they’re still a work in progress. The cells responsible for producing surfactant, a slippery substance that keeps the tiny air sacs in the lungs from collapsing, have been developing since around 20 to 24 weeks. But surfactant levels at 28 weeks are still low compared to what’s needed for easy, independent breathing. The amount of surfactant in the lungs increases steadily from this point through the end of pregnancy, with clinical lung maturity (meaning the lungs can function reliably without medical support) generally not present until around 36 weeks.
This is the main reason babies born at seven months need intensive medical care. Their lungs can exchange oxygen, but often not efficiently enough without help. Surfactant therapy given after birth can compensate for what the lungs haven’t yet produced on their own.
Survival if Born at Seven Months
A baby born at 28 weeks has an 80 to 90 percent survival rate with modern neonatal care. That’s a dramatic improvement over even a few decades ago, and it reflects advances in respiratory support, temperature regulation, and feeding techniques for premature infants. Still, babies born this early typically spend weeks to months in the NICU and face higher risks of complications related to breathing, feeding, vision, and neurological development compared to full-term babies.
Each additional week in the womb at this stage meaningfully improves outcomes. By 31 weeks, when the fetus has grown to about the size of a coconut, the lungs and brain are notably more developed. By 36 weeks, most babies can breathe independently and regulate their own body temperature.
What You Might Be Feeling
With the fetus now over a foot long and actively moving, kicks and rolls are hard to miss at seven months. Many women notice patterns in fetal movement, with the baby tending to be more active at certain times of day (often at night, when you’re lying still). The uterus has expanded well above the belly button, and the growing weight of the baby can put pressure on the lower back, bladder, and ribs. Braxton Hicks contractions, the irregular tightening sensations across the abdomen, become more common during the third trimester as the uterus prepares for delivery.
Your provider will likely begin scheduling more frequent prenatal visits around this time, shifting from monthly to every two weeks. Fetal movement counts, sometimes called “kick counts,” may be recommended as a simple way to monitor the baby’s well-being between appointments. Most providers suggest tracking how long it takes to feel 10 movements. Healthy fetuses at this stage typically reach that number within one to two hours during an active period.