At 29 weeks pregnant, your baby measures about 15.2 inches (38.6 cm) from crown to rump and weighs roughly 2.5 pounds (1,153 grams). That’s about the size of a butternut squash. You’re now well into the third trimester, and your baby is gaining weight faster than at any previous point in the pregnancy.
Weight, Length, and How They’re Measured
The 15.2-inch measurement is crown to rump, meaning from the top of the head to the bottom of the buttocks, not including the legs. If your baby were stretched out fully from head to toe, the total length would be closer to 16 to 17 inches. At 2.5 pounds, the baby has roughly tripled in weight since week 20 and will nearly triple again before delivery.
These are averages. Individual babies vary based on genetics, nutrition, and placental function. Your provider tracks growth through ultrasound estimates and fundal height, which is the distance from your pubic bone to the top of your uterus. At 29 weeks, that measurement should be close to 29 centimeters, give or take about 2 centimeters.
Why Your Baby Is Getting Heavier So Fast
The rapid weight gain happening right now is largely driven by fat. Visible fat deposits begin forming around week 26, and the rate of fat accumulation follows an accelerating curve from this point through delivery. At birth, a full-term baby’s body is roughly 16 percent fat by weight. Most of that, about 80 percent, sits just under the skin as subcutaneous fat.
This fat layer serves two critical purposes. First, it acts as insulation, helping your baby regulate body temperature after birth. Newborns lose heat quickly, and the subcutaneous fat they build during the third trimester is their primary defense. Second, it serves as an energy reserve during the first days of life before breastfeeding or formula feeding is fully established. At 29 weeks, your baby is still in the early phase of this buildup, which is one reason premature babies born at this stage often need help staying warm.
What Your Baby Can Do Right Now
By 29 weeks, your baby’s eyelids have been open for about three weeks. The connection between the eyes and the brain’s visual processing areas establishes itself around week 26, roughly the same time the eyelids separate. Your baby can now detect light that passes through the uterine wall. Research using light projected through the abdomen has shown that fetuses at this stage will actually turn their heads toward patterns that resemble faces, suggesting a surprisingly early visual preference.
Eye movements themselves have been visible on ultrasound since around 15 weeks, but now those movements are more coordinated and purposeful. Your baby is also practicing breathing by inhaling and exhaling amniotic fluid, building the muscle strength and neural pathways needed for breathing air at birth. The brain is developing rapidly, with its surface beginning to form the characteristic folds that increase surface area for neural connections.
Fetal Movement at 29 Weeks
You’re likely feeling strong, distinct kicks, rolls, and flutters by now. As the baby grows and space in the uterus gets tighter, the character of movements may shift from dramatic somersaults to more focused jabs and stretches. This is normal and expected.
The standard guideline for tracking movement is to count 10 kicks, flutters, swishes, or rolls within a two-hour window. Ten movements in one hour is typical, but taking up to two hours is still considered fine. The best time to count is when your baby tends to be most active, often after a meal or in the evening when you’re lying down. If you consistently don’t reach 10 movements in two hours, that’s worth reporting to your provider. The pattern matters more than any single session. A baby who is usually very active and suddenly becomes quiet deserves attention, even if the count technically meets the threshold.
How Your Body Is Changing
Your uterus now extends well above your belly button, pushing organs upward and outward. This can cause heartburn as your stomach gets compressed, shortness of breath as your diaphragm has less room to expand, and more frequent trips to the bathroom as your bladder bears increasing pressure from above. Some women notice their ribs aching as the uterus presses against the lower rib cage.
Weight gain for you at this stage typically runs about a pound per week, though this varies. Swelling in the feet and ankles is common due to increased blood volume and pressure on the veins returning blood from your lower body. Sleeping comfortably becomes harder as side-lying positions become essentially the only option. Many women find a pillow between the knees or under the belly helps.
What 29 Weeks Means for Viability
Babies born at 29 weeks are considered very premature but have strong survival rates, generally above 90 percent in hospitals with neonatal intensive care units. The main challenges for a baby born this early are lung immaturity, difficulty maintaining body temperature (because of that still-developing fat layer), and feeding. Most 29-week preemies spend several weeks in the NICU, typically until close to their original due date, gaining weight and building the stamina to breathe, eat, and regulate temperature independently.
Every additional week in the womb at this stage meaningfully reduces the likelihood and severity of complications. Between weeks 29 and 34, the lungs undergo significant maturation, and the fat stores that support temperature regulation continue their rapid buildup.