28 Weeks Pregnant: Welcome to the Third Trimester
Medically reviewed by
Maureen Kelly, RN — 20+ years in L&D, postpartum, NICU, and women’s health.
Reviewed against ACOG, AAP, and Mayo Clinic guidance. Meet Maureen →
Medical Disclaimer: This article is for informational purposes only. Always consult your healthcare provider.
Welcome to the third trimester! At 28 weeks, your baby is about the size of an eggplant—roughly 15 inches long and weighing about 2.2 pounds. This final stretch brings rapid growth, more frequent prenatal visits, and exciting preparation for your baby’s arrival. Your baby’s brain is developing complex thought patterns, and they may even be dreaming during REM sleep.
Baby Development at 28 Weeks
Your baby measures about 15 inches and weighs approximately 2.2 pounds. The brain is developing rapidly, with billions of neurons forming. Your baby now has REM sleep cycles, which may mean they’re dreaming. Eyes can blink and are sensitive to light.
Fat continues to accumulate under the skin, helping regulate temperature after birth. The lungs are maturing but not yet fully developed. Your baby’s immune system is strengthening with antibodies from you. For a complete overview, see our third trimester guide.
Your Body This Week
Prenatal visits increase to every 2 weeks from now until week 36. Your provider will monitor blood pressure, weight, fundal height, and baby’s position. You may receive the RhoGAM shot if Rh-negative and the Tdap vaccine (whooping cough protection for your baby).
Your belly is large and continuing to grow. You may experience shortness of breath, difficulty sleeping, and increased back pain. Braxton Hicks contractions may be more frequent.
Common Symptoms at 28 Weeks
Shortness of breath: Your uterus presses against your diaphragm. This improves when the baby “drops” near delivery.
Sciatica: Pressure on the sciatic nerve can cause shooting pain down your leg. Stretching and warm compresses help.
Frequent urination returns: The baby’s head is putting pressure on your bladder again.
Braxton Hicks contractions: More frequent practice contractions. Contact your provider if they become regular or painful.
What to Do This Week
Begin kick counts. Track your baby’s movements daily. You should feel at least 10 movements within 2 hours. See our baby movement guide.
Start planning your hospital bag.
Draft your birth plan.
Discuss the Tdap vaccine with your provider. It protects your newborn from whooping cough.
Continue safe exercise. See our guide.
Nutrition Spotlight: Third-Trimester Energy
You need about 450 extra calories daily in the third trimester. Focus on protein (for baby’s rapid growth), complex carbohydrates (for sustained energy), and healthy fats (for brain development). Continue adequate calcium, iron, and DHA. Visit our nutrition guide.
When to Call Your Doctor
- Vaginal bleeding or fluid leaking
- Regular contractions (more than 4-6 per hour before 37 weeks)
- Severe headaches or vision changes
- Sudden severe swelling
- Fewer than 10 movements in 2 hours
- Signs of preterm labor
See our when to call your doctor guide.
Frequently Asked Questions
How do I do kick counts?
Choose a time when your baby is usually active. Lie on your side and count movements. You should feel at least 10 in 2 hours. If you don’t, contact your provider.
What is the Tdap vaccine?
A vaccine given around 27-36 weeks that protects your newborn from whooping cough. Your antibodies pass to the baby, providing protection in their first months of life.
Is it normal to feel anxious about labor?
Very normal. Childbirth classes, talking with experienced parents, and discussing your birth plan with your provider can all help reduce anxiety.
Get weekly pregnancy updates
Key takeaways for the third trimester
- Prenatal visits move to every 2 weeks at week 28, then weekly from week 36.
- Group B strep (GBS) screening is performed between weeks 36 and 37.
- Kick counts become important — track 10 movements within 2 hours during baby’s active period.
- Heartburn, swelling, back pain, frequent urination, and sleep disruption are all common and intensify in the third trimester.
- “Lightening” (baby drops into the pelvis) often happens 2–4 weeks before labor in first pregnancies; sometimes only at the start of labor in subsequent pregnancies.
When to call your provider
Call your OB-GYN, midwife, or labor and delivery unit right away if you experience:
- Heavy vaginal bleeding (more than light spotting)
- Severe abdominal or pelvic pain
- A severe headache that doesn’t respond to acetaminophen
- Sudden facial, hand, or leg swelling
- Vision changes (spots, blurring, light sensitivity)
- Decreased fetal movement after 28 weeks (fewer than 10 movements in 2 hours during baby’s active period)
- Signs of preterm labor: regular contractions, pelvic pressure, low back pain, fluid leaking
- Fever over 100.4°F (38°C)
When in doubt, call. Your provider would always rather hear from you about a non-issue than miss something important.
Frequently asked questions about week 28
How big is the baby at 28 weeks pregnant?
At 28 weeks, your baby is roughly the size of an eggplant (~14.8 inches, 2.2 lb). Size estimates vary from baby to baby and are based on standardized growth charts (ACOG, NICHD).
What symptoms are common at 28 weeks pregnant?
Common third-trimester symptoms include heartburn, swelling in feet and ankles, low back pain, frequent urination, Braxton Hicks contractions, sleep disruption, and a heightened sense of fatigue. The body is preparing for labor.
What prenatal appointments happen around 28 weeks?
Visits move to every 2 weeks at week 28. Tdap vaccination is recommended between weeks 27 and 36.
When should I worry at 28 weeks pregnant?
Fewer than 10 fetal movements in a 2-hour period (during baby’s active time), regular contractions, vaginal bleeding, leaking fluid (possible ruptured membranes), severe headache, sudden swelling, vision changes, or any symptom that just feels wrong warrants immediate evaluation.
Is what I’m feeling at 28 weeks normal?
Most of the symptoms experienced at 28 weeks are part of typical pregnancy and reflect your body’s adjustments. If anything feels alarming, severe, or unusual for you, contact your provider — trust your instincts.
Sources
- American College of Obstetricians and Gynecologists (ACOG). Your Pregnancy and Childbirth: Month to Month (current edition). acog.org
- American Academy of Pediatrics. Caring for Your Baby and Young Child (current edition).
- Mayo Clinic. Pregnancy week by week. mayoclinic.org
- National Institute of Child Health and Human Development (NICHD). Pregnancy and Pregnancy Loss research and guidance.