39 Weeks Pregnant

Baby's Development This Week

In week 39, your baby is putting on weight quickly and fine-tuning their lung and brain function. They are becoming more responsive to light and sound from the outside world as they prepare for the big transition to life outside.

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  The baby is officially full term!
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  The brain has 30 billion neurons.
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  The chest wall is developed enough for effective breathing.
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  Reflexes are coordinated — baby can grasp, suck, blink, and turn the head.
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  The fetus fills the entire uterus.
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  About 50.7cm — the size of a watermelon.

Your Symptoms at Week 39

As you progress through week 39, you may feel more physical strain as your baby grows. Back pain and difficulty finding a comfortable sleeping position are common. Keep your feet up when you can and take pride in how far you've come in this incredible process.

Week 39 Checklist

• ✓Attend weekly prenatal visit (essential)
• ✓Keep your phone charged and hospital bag by the door (essential)
• ✓Rest and sleep as much as possible (essential)
• ✓Review the 5-1-1 rule with your partner (essential)
• ✓Make sure the car seat is installed correctly (essential)

Nutrition in the Third Trimester

By the third trimester, your baby’s growth is at its fastest, and it’s common for appetite, digestion, and comfortable meal sizes to shift again as the growing uterus puts more pressure on the stomach. Many people find smaller, more frequent meals more comfortable than large ones during this stage, and heartburn becomes more common as a result of this physical pressure.

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  Continue your prenatal vitamin through the end of pregnancy — some providers also recommend starting or adjusting iron supplementation in the third trimester depending on bloodwork.
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  Smaller, more frequent meals can ease the heartburn and fullness that often become more pronounced as the uterus takes up more abdominal space.
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  Stay well hydrated — fluid needs remain elevated, and dehydration can contribute to Braxton Hicks contractions.
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  Continue prioritizing protein, iron, and calcium, which remain important for your baby’s rapid growth in the final weeks.
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  Some people find preparing and freezing meals ahead of delivery useful, since appetite and energy for cooking can fluctuate in these final weeks.
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  Continue avoiding alcohol, raw/undercooked proteins, unpasteurized dairy, and high-mercury fish through the end of pregnancy.

Staying Active in the Third Trimester

Exercise in the third trimester often needs to be scaled back in intensity as the belly grows larger and balance becomes more of a factor, but staying appropriately active (if cleared by your provider) can still help with sleep, mood, and physical comfort in these final weeks. Walking and prenatal-specific stretching or yoga are commonly well-tolerated options. Pay attention to your body’s signals more than usual here — this is a stage where providers generally recommend erring toward caution and lower intensity rather than pushing to maintain a pre-pregnancy pace.

For Partners: Supporting the Third Trimester

The final stretch of pregnancy often brings physical discomfort, disrupted sleep, and anticipation (or anxiety) about labor — partners can help by taking on more of the physical tasks around the house, being flexible and present as due-date logistics come together, and learning what to expect during labor so they can be a more active, informed support during delivery. This is also a good time to finalize practical plans together: the route to the hospital or birth center, who to call, and what the first hours after birth might look like.

Frequently Asked Questions