At 25 weeks pregnant, you’re nearing the end of your second trimester with about 15 weeks to go. Your baby is roughly the size of an acorn squash, weighing close to 1.5 pounds and measuring around 13 inches from head to heel. This is a week of significant sensory and respiratory development for your baby, and a time when your own body is adapting to a noticeably larger uterus.
Your Baby’s Lungs Are Preparing to Breathe
One of the biggest milestones happening right now is inside your baby’s lungs. Around week 24 to 25, specialized cells in the lungs begin producing surfactant, a slippery substance that will eventually keep the tiny air sacs from collapsing each time your baby exhales. Without surfactant, breathing outside the womb isn’t possible. Production starts small at this stage and ramps up significantly over the coming weeks, which is one reason why every additional week of pregnancy matters for lung maturity.
The lungs are still structurally immature. Blood vessels are branching throughout the lung tissue, and the air sacs themselves are just beginning to form. Full lung readiness won’t arrive until closer to 36 or 37 weeks, but the groundwork being laid now is critical.
Hearing and Brain Development
Around week 25 or 26, babies in the womb begin responding to voices and noise. Your baby’s inner ear is now developed enough to detect sound vibrations, and the nerve pathways connecting the ear to the brain are becoming functional. You might notice your baby startle or kick in response to a loud sound, a door slamming, or music. Talking and reading aloud at this stage isn’t just sentimental: your baby is genuinely processing the rhythm and tone of your voice.
The brain is growing rapidly, with the cerebral cortex developing more complex folds and layers. Nerve cells are forming connections at an accelerating pace, which supports increasingly coordinated movements. You may notice your baby’s kicks and rolls feel more deliberate than the flutters of earlier weeks.
What You’re Feeling Right Now
Your uterus is now roughly the size of a soccer ball, and your fundal height (the distance from your pubic bone to the top of the uterus) should measure close to 25 centimeters, give or take 2 centimeters. Your provider may start measuring this at prenatal visits as a quick check on your baby’s growth.
Common symptoms at 25 weeks include:
- Leg cramps: Especially at night, often striking the calves. Stretching before bed and staying hydrated can help.
- Hemorrhoids: Increased blood volume and pressure from your growing uterus make these more likely. Eating fiber-rich foods and drinking plenty of water can reduce straining.
- Skin changes: You may notice brown or darkened patches on your face, sometimes called the “mask of pregnancy.” Hormonal shifts can also make your skin oilier or more prone to breakouts. These changes typically fade after delivery.
Heartburn, shortness of breath, and swelling in your feet and ankles are also common as your uterus pushes upward against your diaphragm and adds pressure to the veins in your lower body.
Pelvic Pain and How to Manage It
Some women start feeling a sharp or aching pain at the front of the pelvis around this time. This is often symphysis pubis dysfunction, caused by the hormone relaxin loosening the joint at the front of your pelvis a bit too much. It can feel like a dull ache, a sudden shooting pain, or a grinding sensation when you walk, roll over in bed, or get out of a car.
If this sounds familiar, a few adjustments can make a real difference. Sleep on your side with a pillow between your knees and lower legs. Wear supportive shoes with good cushioning. Avoid sitting in one position for long stretches, and when you get out of a car, squeeze your knees together before swinging your legs out. A pregnancy support belt can help stabilize your pelvis during the day. Swimming is a good exercise option because it takes weight off the joint without sacrificing movement. Pelvic floor exercises and physical therapy can also improve stability and reduce pain.
Tracking Your Baby’s Movement
By 25 weeks, you’re likely feeling regular movement throughout the day. Formal kick counting becomes more important starting around week 28, but getting familiar with your baby’s patterns now is useful. You’ll start to notice your baby has active and quiet periods, often on a schedule that doesn’t match yours (many babies are most active when you lie down at night).
When you do start formal counting in a few weeks, the method is straightforward. Pick a time when your baby is typically active, lie on your left side or sit with your feet up, and count kicks, rolls, swishes, or flutters. You’re looking for 10 movements within two hours. Most babies hit that number much faster. The goal isn’t to count constantly but to learn what’s normal for your baby so you’ll notice if something changes.
Sleep Positions in the Second Half of Pregnancy
You’ve probably heard that sleeping on your left side is best during pregnancy. The reasoning is that your growing uterus can press on major blood vessels when you lie flat on your back, potentially reducing blood flow to you and your baby. Research suggests that sleeping position during early and mid-pregnancy (up to about 30 weeks) doesn’t significantly affect the risk of complications. But as your uterus gets heavier through the third trimester, side sleeping becomes more important.
At 25 weeks, you’re in a transition zone. If you can comfortably sleep on your side, it’s a good habit to build now. A pillow between your knees, behind your back, or a full-body pregnancy pillow can keep you from rolling onto your back overnight. If you wake up on your back, don’t panic. Just shift to your side and settle back in.
What’s Happening at Prenatal Visits
If you haven’t already, your provider will likely order your glucose screening test sometime between now and week 28. This involves drinking a sugary solution and having your blood drawn an hour later to check how your body processes sugar. It screens for gestational diabetes, which affects roughly 6 to 9 percent of pregnancies. The test itself is quick, though some women find the drink unpleasant.
Your blood pressure, weight, and urine will be checked at each visit. Fundal height measurements become routine. These simple checks, combined with your report on how the baby is moving, give your provider a clear picture of how things are progressing without any invasive procedures.