Now that you're 33 weeks along, you're approaching the middle of the third trimester.

By now, your baby has reached the length he'll measure at birth, but he's still busy putting on about half a pound a week.

You might notice this rapid growth in the form of sharper kicks (oof) and shortness of breath, thanks to crowding around your lungs.

Your Baby at Week 33

At a Glance

Soft spot
Soft spot
The plates of bone in your baby’s skull are still fairly pliable, which makes it easier for him to squeeze down the birth canal.
Thirsty baby
Thirsty baby
Your baby drinks up to a pint of amniotic fluid a day! This helps prepare your baby’s gastrointestinal system for prime time.
Packing on the pounds
Packing on the pounds
Your baby is gaining weight at a fast clip now, putting on about half a pound a week. He'll come close to doubling his weight by the time he's born.

33 weeks pregnant is how many months?

If you're 33 weeks pregnant, you're in month 8 of your pregnancy. Only 1 month left to go! Still have questions? Here's some more information on how weeks, months and trimesters are broken down in pregnancy.

How big is my baby at 33 weeks?

This week your baby may be anywhere between 16 and 17 or more inches in length and could grow up to another full inch this week — especially if he's been on the shorter side.

He weighs more than 4¼ pounds and is still gaining weight at a rate of about half a pound a week. Weight gain can range from a third more to a full doubling before the big debut.

Baby's kicks may feel sharper

With that much baby inside your uterus, your amniotic fluid level has maxed out at 33 weeks pregnant, making it likely you have more baby than fluid now. That's one reason why some of his pokes and kicks feel pretty sharp these days.

Baby differentiates day from night

If your uterus had eyes, here's what you'd see: your fetus acting more and more like a baby, with his eyes closing during sleep and opening while awake.

And because those uterine walls are becoming thinner, more light penetrates the womb, helping your baby differentiate between day and night. Now if only baby can remember that difference on the outside!

Fetal immune system is developing

Good news! Your baby has reached an important milestone about now: He's got his own immune system. Antibodies are being passed from you to your little one as he continues to develop his fetal immune system, which will come in handy once he's outside the womb and fending off all sorts of germs.

Your Body at Week 33

33 Weeks Pregnant

Insomnia

With the hormonal changes, midnight bathroom runs, leg cramps, heartburn and your basketball-sized belly, it's no wonder sleep is elusive. Third trimester insomnia strikes about 3 in 4 pregnant women — who may also be coping with anxiety about the upcoming birth and a mind that races all night long thinking about their to-do-before-the-baby-comes list.

At 33 weeks pregnant, your body needs rest, so remember that worrying about it won't help and neither will staring at the clock watching the minutes tick by.

Instead, do your best to get comfy — before bed and when you get in it. Try a warm bath and perhaps a warm cup of milk before turning in, plus avoid exercising, screen time, eating or drinking too close to bedtime. You can also try asking your partner for a massage. You deserve it!

If sleep still eludes you, read a book or listen to soothing music until drowsiness sets in. And look on the bright side: Pregnancy insomnia is great training for those sleepless nights to come!

Omega-3 fatty acids

Studies suggest that infants born to mothers whose diets contain plenty of omega-3 fatty acids (DHA) found mostly in fish oils have an edge in terms of early development.

So if you eat your wild salmon, will your kid go to Harvard? Maybe, maybe not. But DHA is critical to brain and vision development — and almost all of a baby's accumulation of DHA occurs during the last trimester. DHA may also help prevent preterm labor and protect against postpartum depression.

But haven't you heard that fish is unsafe for pregnant women? Actually, the Food and Drug Administration (FDA) recommends eating 8 to 12 ounces (or about two to three average meals) a week of a variety of well-cooked fish and shellfish that are low in mercury, such as shrimp, tilapia, flounder, salmon (wild is best), pollack and catfish. Steer clear of swordfish, shark and bigeye tuna, which are more likely to contain higher levels of mercury.

Hate fish? Other DHA sources include algae-derived supplements, though check your health food store and ask your practitioner before buying a bottle, and DHA-enriched eggs, available in most supermarkets. Or try these tasty omega-3-rich and pregnancy-friendly meal ideas.

Pregnancy Symptoms Week 33

Strong fetal movement
Strong fetal movement
Varicose veins
Varicose veins
Round ligament pain
Round ligament pain
Nail changes
Nail changes
Shortness of breath
Shortness of breath
Clumsiness
Clumsiness
Pregnancy brain
Pregnancy brain
Braxton Hicks contractions
Braxton Hicks contractions

Tips for You This Week

Look into breastfeeding

About 83 percent of women try breastfeeding after giving birth, according to the Centers for Disease Control and Prevention (CDC). Will you be one of them?

If so, now’s a great time to talk to your practitioner about it, watch some instructional videos, read up on it, or even take a breastfeeding class if you're able to.

Thinking about room-sharing?

Find out your hospital’s policy on rooming-in — sharing a room with your baby 24/7 after you give birth. 

Though it's completely your choice, it can be a good experience for you and your baby if you want to give it a try. But it’s okay if you decide not to room-share too!

Narrow down your list of names

Choosing a name for your baby is one of the biggest early decisions you’ll make as a parent. Will you select a popular name or a more unique one? Will you go with a traditional boy or girl’s name or a gender-neutral one

Think about how the name will sound with your child’s last name (or names), and what the initials will spell. And consider the shortened form of your top selections — your child may pick up a nickname whether you like it or not!

Switch to light weights

Yes, weight training increases muscle tone — and even prevents bone loss — but during pregnancy it's important to lighten up.

Lifting heavy weights increases pressure in your body, which causes you to hold your breath and could compromise blood flow to the uterus. Plus, loosened ligaments could lead to injury.

Your best bet: Switch to light weights and do more reps — or just wait on weights until after delivery.

Write a letter to your little one

You've got so many hopes and dreams about your baby, and each one is worth remembering and sharing. Record them before you forget by writing a letter — or a series of letters — to your baby.

Feel a little funny writing to a fetus? Just speak from the heart. Talk about what this pregnancy means to you and how it's changing your body and your world. Recount the foods you craved, the way you finally chose your baby’s name and what colors you picked for the nursery.

Share your reaction when you first found out you were pregnant, when you felt those first kicks and when you found out your baby's sex (if you have). Imagine what you'll do together in the future. Do you see yourself pushing a swing in the park or tossing a football on the front lawn? Or imagine what your baby's future might be like.

Your letter to your baby is certain to become one of your most treasured possessions — and eventually, your child's.

Prevent an upset stomach

If your body has trouble digesting lactose (a type of sugar), you may find that drinking milk can lead to cramps, gas, bloating and diarrhea.

Sure, you could buy lactose-free milk or pop a lactase capsule before downing a glass of the stuff, but there are other ways to crank up your calcium consumption and avoid an upset stomach.

One solution: Get active with active yogurt cultures: They harbor good bacteria that break down lactose. Or, eat naturally aged hard cheeses like cheddar, Parmesan and Swiss, which lose more than half their lactose during processing. Just make sure they’re pasteurized — and most cheeses in the U.S. are — since unpasteurized ones can be contaminated with listeria, a harmful bacterium.

You can also cut back on the amount of milk you drink. It’s possible that your stomach can handle smaller servings, like a half a cup at one sitting or a thin slice of mozzarella.

Lastly, since lactose is easier to digest when mixed with other foods, particularly high-fiber ones, take your milk with whole grain cereal, or melt that cheese on a slice of whole wheat bread.

Sleep on your side

It’s been a little while since you’ve been able to sleep on your back — or your belly, for that matter — but now that you're officially a side sleeper, consider rolling onto your left side at night (though either side works).

Why? Some experts say that the left side is the ideal sleeping position for both you and your baby, since it allows for maximum blood flow and nutrients to the placenta. It may also help ease the swelling in your feet, ankles and hands.

If you do roll onto your back during the night or just can’t get comfortable on your side, tilt your hips to one side and place a pillow under one side of your bottom for support.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.

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  2. WhatToExpect.com, Breastfeeding: Basics and Tips for Nursing Your Baby, January 2022.
  3. WhatToExpect.com, Sleeping Positions During Pregnancy, December 2022.
  4. WhatToExpect.com, Diarrhea During Pregnancy, July 2021.
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  6. Centers for Disease Control and Prevention, Breastfeeding Report Card, 2018.
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  14. National Institutes of Health, National Library of Medicine, Amniotic Fluid, November 2022.
  15. National Institutes of Health, National Library of Medicine, Calcium in Diet, January 2023.
  16. National Institutes of Health, National Library of Medicine, Selective and Persistent Effect of Foetal Sex on Cognition in Pregnant Women, May 2005.
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  18. National Institutes of Health, NIH Osteoporosis and Related Bone Diseases National Resource Center, Pregnancy, Breastfeeding, and Bone Health, May 2023.
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  22. U.S. Department of Agriculture, National Agricultural Library, Aquaculture and Aquaponics.
  23. WhatToExpect.com, How Many Weeks, Months and Trimesters in a Pregnancy?, May 2022.
  24. WhatToExpect.com, How Much Weight Should You Gain During Pregnancy?, July 2022.
  25. WhatToExpect.com, Are Pregnancy Mood Swings Normal?, October 2023.
  26. WhatToExpect.com, Insomnia During Pregnancy, November 2022.
  27. WhatToExpect.com, Omega-3 Foods and Fish Oil During Pregnancy, November 2021.
  28. WhatToExpect.com, Postpartum Depression (PPD), April 2021.
  29. WhatToExpect.com, Eating Fish During Pregnancy: What Varieties Are Safe?, June 2022.
  30. WhatToExpect.com, A Mom's Guide to a Hospital Birth, July 2023.
  31. WhatToExpect.com, Top 1,000 Baby Boy Names in the U.S., May 2023.
  32. WhatToExpect.com, Top 1,000 Baby Girl Names in the U.S., May 2023.
  33. WhatToExpect.com, Unisex Baby Names, November 2021.
  34. WhatToExpect.com, Is It Safe to Lift Weights While Pregnant?, November 2021.

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