GUIDE
Your baby can open and close their eyes, sleeps and wakes at regular intervals, and the third trimester begins at the end of this week.
At the size of a head of lettuce, your baby weighs about 2 pounds and is practicing the skills they will need after birth.
Be prepared from day one
Your baby is about the size of a head of lettuce — approximately 14.5 inches long and weighing around 2 pounds. This is the last week of the second trimester, and your baby is putting the finishing touches on several important developmental milestones.
Your baby can now open and close their eyes regularly and has well-established sleep-wake cycles. During active periods, your baby may kick, punch, roll, hiccup, and even suck their thumb. During sleep periods, they are relatively still. Many parents notice a pattern to these cycles — babies are often most active in the evening or when you are resting and your movements are not lulling them to sleep.
The brain is growing rapidly, with the surface beginning to develop the characteristic folds and grooves (called sulci and gyri) that dramatically increase its surface area. This folding allows more brain cells to pack into the skull and is associated with increasing cognitive complexity. The brain is now controlling more sophisticated functions, including regulating body temperature and directing rhythmic breathing movements.
Your baby's lungs are continuing to mature but are still not ready for independent breathing. Surfactant production is increasing steadily, and the network of tiny blood vessels in the lungs is expanding. If your baby were born now, they would likely need respiratory support — but survival rates at 27 weeks are high, around 90%, with access to neonatal intensive care.
Since last week, the eyes continue to develop, and the fat layer beneath the skin is getting thicker, helping to smooth out wrinkles and regulate temperature.
Welcome to the transition zone between second and third trimesters. Your body has done incredible work to get here, and you can probably feel every bit of it.
Shortness of breath is a near-universal complaint at 27 weeks. Your uterus is pushing your diaphragm upward by about 1.5 inches, which reduces your lung capacity. At the same time, progesterone makes you breathe more deeply, which can paradoxically make you feel like you are not getting enough air. This will improve slightly later in pregnancy when the baby drops lower into your pelvis.
Braxton Hicks contractions are likely becoming more frequent and noticeable. They should still be irregular, painless (or mildly uncomfortable), and resolve with rest or hydration. As you enter the third trimester, it becomes increasingly important to know the difference between Braxton Hicks and true preterm labor contractions — regular, painful contractions that get closer together and do not stop with position changes.
Sleep may feel like a distant memory. Between the physical discomfort, frequent urination, leg cramps, heartburn, and your baby's nocturnal dance sessions, uninterrupted sleep is rare. Do your best to prioritize rest — even if it comes in fragments. Napping during the day, if possible, is not lazy; it is necessary.
Swelling in your feet, ankles, and hands continues. Back pain and pelvic pressure are also likely increasing as your baby gains weight and your joints continue to loosen in preparation for birth.
Every pregnancy is different. The transition to the third trimester is a good time to have an honest conversation with your provider about how you are feeling — physically and emotionally.
As you prepare to cross into the third trimester, this week is about planning, paying attention, and giving yourself grace.
If you plan to deliver at a hospital or birth center, schedule a tour now. Knowing the route, where to park, where to check in, and what the rooms look like will make the day feel less overwhelming. Ask about their policies on visitors, labor support, and skin-to-skin contact.
A birth plan is a living document — start the conversation with your provider now about your preferences for pain management, labor positions, who will be in the room, and your wishes for the immediate postpartum period. Your provider can help you understand what is realistic and what alternatives are available.
As you cross into the third trimester, consider what still needs to happen: finishing the nursery, washing baby clothes, installing the car seat, packing a hospital bag. Make a list and tackle it bit by bit while you still have relatively good energy and mobility.
You should be very familiar with your baby's active and quiet times by now. While formal kick counting is typically recommended starting at 28 weeks, start paying close attention to any significant changes in your baby's normal activity pattern. A sudden decrease in movement should always be reported to your provider.
When in doubt, call your provider. As you approach the third trimester, any potential signs of preterm labor or preeclampsia should be evaluated promptly.
Week 28 marks the official start of the third trimester — the home stretch. Your baby will be the size of an eggplant, may begin turning head-down, and kick counts are recommended from this point forward. You may also have more frequent prenatal appointments.
If the glucose screening test has not been done yet, it should happen in the next couple of weeks. And if weight gain is on your mind, the third trimester is when you will gain the most — about a pound per week is typical.
This guide is for informational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider with any questions about your pregnancy.
