At 25 weeks pregnant, you are in your sixth month of pregnancy. You’re also in the second trimester, which spans weeks 14 through 28. That puts you in the final stretch before the third trimester begins.
Why Weeks and Months Don’t Line Up Neatly
Pregnancy math is confusing because calendar months aren’t exactly four weeks long. Most months have 30 or 31 days, which means they contain about 4.3 weeks rather than a clean four. Over nine months, that difference adds up. So when your app says 25 weeks, you can’t just divide by four and get a precise month. The simplest breakdown: weeks 25 through 28 make up the back half of month six, and once you pass week 28, you enter both month seven and the third trimester.
What’s Happening With Your Baby at 25 Weeks
Your baby is roughly the size of an eggplant and weighs around 1.5 pounds. This is a period of rapid growth, especially in the lungs and brain.
The lungs are in what’s called the canalicular stage of development, which runs from about weeks 22 to 25. During this phase, the airways are branching out and blood vessels are forming around them, building the architecture your baby will eventually need to breathe air. However, the cells that produce surfactant, the slippery substance that keeps air sacs from collapsing after birth, aren’t active yet at this stage. That’s one reason babies born this early need significant respiratory support.
Your baby can hear sounds now, responds to light, and is developing more coordinated movements. You’re likely feeling kicks and rolls regularly, and your provider may ask you to start paying attention to those movement patterns.
If a Baby Is Born at 25 Weeks
Twenty-five weeks is considered viable but extremely premature. A large study published in Pediatrics, covering nearly 23,000 infants born between 2020 and 2022 at hospitals with advanced neonatal units, found that 82% of babies born at 25 weeks survived to hospital discharge. That’s a significant number, but survival often comes with challenges. Only about 43% survived without severe complications.
Babies born this early typically spend around 110 days (roughly 3.5 months) in the NICU. At discharge, nearly 45% still needed supplemental oxygen, and a smaller percentage went home with feeding tubes or other support. These numbers reflect the reality that while modern medicine gives 25-week babies a strong chance of survival, their lungs, brains, and digestive systems still have weeks of critical development ahead.
Common Symptoms You Might Feel
At 25 weeks, your uterus has grown well above your belly button. Your provider measures the distance from your pubic bone to the top of your uterus (called fundal height) at each visit, and at this stage that measurement should be close to 25 centimeters, give or take 2 centimeters. This measurement helps track whether your baby is growing on schedule.
Many women at this point notice increased back pain as their center of gravity shifts, heartburn from the uterus pressing upward against the stomach, and swelling in the feet and ankles. Braxton Hicks contractions, those irregular tightening sensations across your belly, often become noticeable around this time. Leg cramps, especially at night, are also common. Round ligament pain, a sharp pulling sensation on the sides of your lower belly, can flare up when you change positions quickly.
Medical Screenings Around Week 25
This is a key window for the glucose challenge test, which screens for gestational diabetes. The test is typically done between weeks 24 and 28, so your provider will likely schedule it soon if they haven’t already. The process is straightforward: you drink a sugary liquid containing 50 grams of sugar, wait one hour without eating or drinking anything besides water, and then have your blood drawn. If your blood sugar comes back higher than expected, you’ll be asked to do a longer, more detailed version of the test to confirm whether gestational diabetes is present.
Your provider may also run blood tests around this time to check your iron levels and blood count, since anemia becomes more common as your blood volume increases during pregnancy. At each visit, your blood pressure and weight are checked, and you’ll hear your baby’s heartbeat with a handheld Doppler device. This is also a good time to ask about any vaccinations recommended during pregnancy and to bring up concerns about sleep, mood, or anything else on your mind.
What to Pay Attention To
Now that you’re feeling regular movement, getting familiar with your baby’s patterns matters. You don’t need to count kicks obsessively, but notice what’s normal for your baby. A sudden decrease in movement is worth calling your provider about.
Watch for signs of preterm labor: regular contractions (not the random Braxton Hicks kind), pelvic pressure that feels different from usual, lower back pain that doesn’t go away, or any fluid leaking from your vagina. Swelling is normal at this stage, but sudden, severe swelling in your face or hands, along with a bad headache or vision changes, could signal a blood pressure problem that needs immediate attention.