At six months pregnant (roughly weeks 24 through 27), you’re wrapping up the second trimester and approaching the home stretch. Your baby weighs about 1 to 2¼ pounds by the end of this month, measures around 13 to 14 inches long, and is developing the lung tissue needed to eventually breathe air. Meanwhile, your body is shifting in noticeable ways, from a growing belly that may now draw comments from strangers to new aches that come with carrying more weight up front. Here’s what’s actually happening, week by week and symptom by symptom.
What Your Baby Is Doing Right Now
The sixth month is a busy period for your baby’s lungs, brain, and senses. Around week 23, the lungs begin producing surfactant, a slippery substance that will eventually allow the tiny air sacs to inflate and deflate without sticking together. Your baby can’t breathe air yet, but this is the critical groundwork for that ability. By week 27, the baby weighs roughly 2¼ pounds (about 1 kilogram) and is approximately 13¾ inches long from head to heel.
Your baby’s eyes are active now too. Rapid eye movements start around week 23, and by week 25, most sleep time is spent in REM sleep, the phase associated with dreaming. The skin is still thin, wrinkled, and somewhat translucent, with a pinkish-red tint from blood vessels visible beneath it. A layer of fine, downy hair called lanugo covers the body, helping hold a waxy coating on the skin that protects it from the surrounding amniotic fluid.
You’re likely feeling regular movement by now: rolls, kicks, jabs, and hiccups. These movements may follow a pattern you’re starting to recognize, with active periods and quiet stretches. Formal kick counting is typically recommended starting at week 28, but getting familiar with your baby’s rhythms now is helpful. The general benchmark is 10 movements (kicks, rolls, or flutters) within two hours.
How Your Body Is Changing
Your uterus is now well above your belly button. After week 24, the distance from your pubic bone to the top of your uterus (measured in centimeters) roughly matches the number of weeks you are pregnant, give or take about 3 centimeters. So at 27 weeks, that measurement would be around 27 centimeters. Your provider will start checking this at appointments as a quick gauge of whether the baby is growing on track.
Weight gain during the second and third trimesters averages about 1 pound per week for people who started pregnancy at a normal weight or who were underweight. If you started pregnancy overweight, the expected rate is closer to half a pound per week. These are averages, not rigid targets. Some weeks you’ll gain more, others less.
As your belly grows, your center of gravity shifts forward. Lower back pain becomes more common, and you may notice your posture changing to compensate. Round ligament pain, that sharp or pulling sensation on the sides of your lower abdomen, can flare up when you stand quickly or change positions. Swelling in your feet and ankles often picks up this month too, especially at the end of the day or in warm weather.
Braxton Hicks Contractions
Many people start noticing Braxton Hicks contractions around this time. These are practice contractions: your uterus tightening and then relaxing. They tend to show up when you’re especially active, dehydrated, have a full bladder, or after sex. They feel more like uncomfortable pressure than actual pain, usually in the front of your abdomen or one isolated area.
The key differences between Braxton Hicks and real labor contractions are predictability and progression. Braxton Hicks are irregular, don’t get closer together over time, and often stop entirely if you change position, drink water, or rest. They may last anywhere from less than 30 seconds to about 2 minutes. True labor contractions, by contrast, come at regular intervals, get progressively stronger and longer, start in the mid-back and wrap around to the front, and don’t go away when you move. If contractions become regular or increasingly painful before 37 weeks, that warrants a call to your provider.
The Glucose Screening Test
Between weeks 24 and 28, you’ll be screened for gestational diabetes. This is one of the defining appointments of the sixth month. The most common version is the glucose challenge test: you drink a very sweet liquid containing a measured amount of sugar, then have your blood drawn one hour later. You don’t need to fast beforehand.
If your blood sugar comes back at 140 mg/dL or higher, that doesn’t mean you have gestational diabetes. It means you’ll need to come back for a longer, more precise follow-up test that requires fasting. Gestational diabetes is manageable when caught, which is why this screening is routine rather than optional. If you have risk factors (family history of diabetes, a higher BMI, or gestational diabetes in a previous pregnancy), your provider may have already tested you earlier.
Sleep Gets Harder
Sleeping comfortably becomes a real challenge around the sixth month. There’s a specific reason you’ve probably been told to avoid lying flat on your back: once the uterus is large enough (generally after 20 weeks), it can press down on the large vein that returns blood from your lower body to your heart. This compression can lower your blood pressure and reduce blood flow to the baby. It typically happens in the supine position because gravity pushes the uterus back against your spine, where that vein runs.
The fix is straightforward. Sleeping on your side, particularly your left side, shifts the uterus off the vein and restores normal circulation. A pillow between your knees and another behind your back can help you stay on your side through the night. If you wake up on your back, don’t panic. Simply roll over. Your body will often wake you up with dizziness or discomfort before any real problem develops.
Nutritional Priorities This Month
Your baby’s skeleton is hardening and blood volume is expanding, which means your need for both calcium and iron is high. The recommended calcium intake during pregnancy is about 1,200 milligrams per day. That’s roughly the equivalent of four servings of dairy, though leafy greens, fortified foods, and supplements can fill gaps. Iron needs also increase significantly as your body produces more blood to support the placenta and baby. Iron from food (red meat, beans, fortified cereals, spinach) is absorbed better when paired with vitamin C from sources like citrus or bell peppers.
If you’re dealing with heartburn or constipation, both are common this month. The growing uterus pushes against your stomach and slows digestion. Smaller, more frequent meals and staying well hydrated can help with both. Iron supplements, if you’re taking them, can worsen constipation, so mention it to your provider if it becomes a problem.
Warning Signs to Know
Preeclampsia can develop in the late second trimester, though it’s more common in the third. The hallmark signs are high blood pressure and protein in the urine, which your provider checks at every appointment. Symptoms you’d notice yourself include a severe headache that won’t go away, vision changes like blurriness or seeing spots, swelling in your face and hands (not just the normal foot swelling), and pain in your upper right abdomen. Nausea and vomiting that appear for the first time in mid-pregnancy, rather than lingering morning sickness, can also be a signal.
A related condition called HELLP syndrome can cause easy bruising, abdominal pain, nausea, and extreme fatigue. Both conditions require prompt medical attention because they can escalate quickly. Knowing these symptoms matters more than worrying about them. Most pregnancies at six months are progressing exactly as they should, and routine prenatal visits are specifically designed to catch these issues early.