The 7th month of pregnancy covers roughly weeks 25 through 28, marking the beginning of the third trimester. This is when your baby undergoes rapid brain development, gains significant weight, and reaches a major viability milestone. For you, the physical demands ramp up noticeably as your body supports a baby that now weighs about 2¼ pounds. Here’s what’s happening on both sides.
How Big Your Baby Is Now
By the end of month seven (around 28 weeks), your baby measures about 10 inches from the top of the head to the tailbone and weighs roughly 2¼ pounds (1,000 grams). That’s about the size of a large eggplant. Growth accelerates from here, with your baby gaining about half a pound per week through the rest of the third trimester as fat layers build up under the skin. This fat serves two purposes: it helps regulate body temperature after birth and gives your baby that fuller, less wrinkly appearance.
Lung Development and Surfactant
The lungs are one of the last organs to fully mature, and month seven is a critical window. Specialized cells in the lungs begin producing surfactant, a slippery substance that keeps the tiny air sacs from collapsing when a newborn takes a breath. These cells differentiate between weeks 24 and 34, so at 28 weeks your baby’s lungs are actively building this system but aren’t finished yet. That’s why babies born at this stage typically need breathing support in a neonatal intensive care unit, even though their survival odds are strong.
Brain and Sensory Milestones
The 7th month is a breakthrough period for your baby’s brain and senses. The brain’s surface, previously smooth, starts developing the characteristic folds and grooves that allow for more complex neural connections. Your baby is now cycling between sleep and wake states, and early patterns of REM sleep (the kind associated with dreaming) begin to emerge.
Hearing sharpens dramatically during this stretch. While initial responses to sound begin around 23 weeks, by 28 to 30 weeks all fetuses show consistent reactions to noise. Your baby can detect changes in pitch and responds first to low-frequency sounds (deep voices, bass tones) before picking up higher-pitched sounds closer to 29 to 31 weeks. Research shows that sounds heard regularly during the third trimester can influence sleep and heart rate patterns after birth, which is why your baby may already be learning the rhythm of your voice.
The eyes, which were fused shut until recently, can now open and close. Your baby can perceive changes in light filtering through the uterine wall, though vision remains the least developed sense at this stage.
What Survival Looks Like at 28 Weeks
One of the most reassuring facts about reaching 28 weeks: if your baby were born now, the survival rate is approximately 94%. That number comes with caveats. Among survivors assessed at two years of age, about 49% had no or only mild developmental issues, while 29% had moderate impairment and 21% had severe impairment. Roughly 8% developed cerebral palsy, and a smaller percentage needed hearing aids or vision support. These outcomes improve with each additional week in the womb, which is why every day of the third trimester counts.
Physical Changes You’ll Notice
Your uterus now sits well above your belly button, and at 28 weeks the top of it (measured from your pubic bone) should be roughly 26 to 30 centimeters. Your provider will start measuring this distance, called fundal height, at each visit. The number in centimeters generally matches your week of pregnancy, plus or minus two. Measuring significantly larger or smaller doesn’t always signal a problem. It could mean your due date is slightly off, you’re carrying in a certain position, or you have strong abdominal muscles. But it can also flag growth issues, so an ultrasound usually follows if the measurement seems off.
Swelling in your feet, ankles, and hands becomes more common as your blood volume increases and your growing uterus puts pressure on veins that return blood from your lower body. Mild swelling is normal. Sudden or severe swelling, especially in your face or hands, is worth reporting to your provider promptly.
You may also start feeling Braxton Hicks contractions: irregular tightenings across your belly that come and go unpredictably. They tend to be triggered by dehydration, physical activity, a full bladder, or even sex. The key difference from real labor contractions is that Braxton Hicks don’t follow a pattern, don’t get progressively stronger, and typically stop when you change positions or take a walk. Real labor contractions come at regular intervals, last 30 to 90 seconds each, and intensify over time to the point where talking or walking becomes difficult.
Other common symptoms this month include shortness of breath (your uterus is pressing upward against your diaphragm), heartburn, back pain, trouble sleeping, and more frequent trips to the bathroom as the baby presses on your bladder.
Screenings and Tests This Month
The glucose challenge test for gestational diabetes is typically scheduled between weeks 24 and 28, so it often falls right in the 7th month. You’ll drink a sugary solution, then have your blood drawn an hour later. If your blood sugar comes back at 140 or higher, you’ll return for a longer fasting glucose test to confirm or rule out gestational diabetes.
If your blood type is Rh-negative (meaning your red blood cells lack a specific protein), you’ll receive an injection between weeks 26 and 28. This prevents your immune system from producing antibodies against your baby’s blood cells in case they’re Rh-positive. Without this treatment, those antibodies could cause serious complications in this pregnancy or future ones.
Your provider will likely also check your iron levels, blood pressure, and urine at each visit. Prenatal appointments typically shift from monthly to every two weeks around this point.
Kick Counting Starts Now
Around 28 weeks, many providers recommend you begin tracking your baby’s movements daily. The most common method is simple: pick a time when your baby is usually active (often after a meal), sit or lie down, and count how long it takes to feel 10 distinct movements. Most babies reach 10 within 30 minutes to two hours. What matters most isn’t hitting a specific number but getting familiar with your baby’s normal pattern. A noticeable change in that pattern, like taking much longer than usual to feel movement or a sudden decrease in activity, is worth a call to your provider.
Nutrition in the Third Trimester
Your calorie needs increase to about 2,400 per day during the third trimester, roughly 200 more than the second trimester and 600 more than the first. But the quality of those calories matters more than the quantity. Iron is especially important now because your baby is building its own blood supply, and your expanded blood volume means you need more too. Low iron is one of the most common issues in the third trimester and can leave you exhausted beyond what’s normal for pregnancy.
Calcium supports your baby’s rapidly hardening bones, and omega-3 fatty acids (found in fish, walnuts, and flaxseed) play a role in brain development during this period of rapid neural growth. If you’re eating a varied diet with plenty of protein, whole grains, fruits, and vegetables, you’re likely covering most of your bases, though your provider may recommend specific supplements based on your bloodwork.