The Third Trimester: Your Complete Guide

Team Peanut11 months ago8 min read

Woah now, mama! You’re almost there. The most exciting finishing line of your life is coming up quickly. Soon you’ll be meeting your baby. The third trimester is a time for packing on the pounds (for baby, anyway), and resting – and nesting – for you. So let’s get ready for that baby!

Third trimester

Here’s our guide to what to expect during the third trimester of pregnancy.

When does the third trimester start?

The third trimester starts at week 28 of your pregnancy and lasts, well, as long as it takes to get that baby outta there!

You’ll be classed as “full term”, meaning your baby is ready to be earthside, at 39 weeks. If your little one isn’t showing signs of arrival, and there are no health issues for either of you, you might reach 42 weeks pregnant before medical intervention (like induction or cesarean birth).

It’s actually pretty rare for babies to be born on their due date so although you may have that magical date set in your mind, your baby might have other plans. So try to keep cool, be prepared, and enjoy these last months of pregnancy.

How do you feel in the third trimester?

The third trimester can play host to a range of emotions, from fear of your impending birth experience and motherhood to excitement for the amazing journey you’re on.

Whatever you’re feeling, remembering these three things can help you to deal with common third-trimester symptoms:

  • Listening to your body. As your baby grows, the physical demands on your body get bigger too, so know your limits.
  • Trusting your instinct. If something doesn’t feel or look right, always get checked out by a healthcare professional.
  • Resting as much as possible. To reduce physical and mental stress in this last trimester.

Common third-trimester symptoms

Physically, the third trimester can be a culmination of all the symptoms of trimesters passed, and then some! You may have fatigue and heartburn to deal with again, like in the first trimester, and some second trimester symptoms like leg cramps, round ligament pain, and Braxton Hicks contractions too.

Some new symptoms to be aware of for these last months of pregnancy are:

Crazy dreams

Dreamt you gave birth to a pony or was that just me?! Yep, all that real-life anxiety/excitement you’re feeling is working its way into your dreams, and they’re super vivid, too. Not great if you’re struggling to sleep anyway, but makes for fun conversations over breakfast.


Say hello to your new friend, “baby brain”! Are you feeling foggy, forgetting everything, losing things, dropping stuff, not able to make a plan? Research has proven that “baby brain” is a very real thing, not just an old wives’ tale, so try not to get too frustrated with yourself. You’ll be back to your old self again soon!

Leaky boobs

As your due date gets closer, you may find that your nipples start producing a thick, yellowish substance. This is called colostrum and it’s a super-concentrated form of breastmilk that’s full of nutrition for your newborn’s tiny tummy.

Lightning crotch

Lightning crotch is a sharp, shocking pain down below. Kinda like your nether regions are being struck by lightning. Sounds fun, right?! It’s more likely to happen later on in the third trimester when your baby is positioned very low down and is a bit tight on space.

Increased discharge

Similar to the first trimester, it can be normal around now to see a bit more of that milky white discharge (leukorrhea). If it’s mucousy or streaked with blood, it could be your mucus plug, which sounds gross but it plays an important role in keeping your baby safe in utero.

Losing your mucus plug can be an early sign of labor (ahh, it’s happening!), so keep an eye on it and speak to your midwife.

What to look out for in the third trimester

It’s understandable to be on high alert at this final stage of pregnancy, looking out for signs of labor.

While discomfort is quite normal (sorry about that!), if you have any severe lower abdominal pain, vaginal bleeding, vomiting, pain when you pee, or fever in the third trimester, don’t wait for your next antenatal appointment - speak to your doctor or midwife as soon as you can.

What is your baby doing in the third trimester?

For your baby, the third trimester is about those finishing touches and a whole heap of growing. Throughout months 7, 8, and 9 (and maybe 10!) of your pregnancy, your baby may grow up to 15cm in length and more than triple their weight.

Yikes! No wonder you’ve got that pregnancy waddle going on these days!

Here’s what your baby’s getting up to in there.

Weeks 28-32

Your baby grows to the size of a squash (about 41cm)
Your baby will be transforming their cartilage skeleton into bone, so make sure you’re still taking a pregnancy vitamin and eating plenty of calcium-rich foods. Their skull will remain softer, to make vaginal delivery easier – phew! And they’ll have distinct periods of sleep and activity, so it’ll probably be easier to track their movements, too.

Weeks 33-37

Your baby grows to the size of a romaine lettuce (about 49cm)
Baby’s skin will turn opaque as it thickens and their fat reserves will increase, getting ready for those cute chubby-cheeked newborn photos! Most babies will turn themselves into a head-down position in these weeks (sometimes earlier) to get ready for birth.

If your baby stays head up, this is called “breech”, and your doctor may talk to you about trying to turn the baby before labor begins.

Weeks 38-42

Your baby grows to the size of a watermelon (about 53cm)
Around now, the furry coating of hair and waxy vernix that has been keeping your baby warm will start shedding, but don’t be surprised if a little remains when they’re born, especially if you give birth before your due date. Your baby’s lungs have matured, they’re able to suck their thumb, and cry, so that’s it. It’s just a waiting game now, mama. Your baby is ready to meet you!

What to do in the third trimester

You’ve probably still got plenty of time before your baby makes an appearance, but there’s no harm in being prepared. Here are some good ideas for what to do in your third trimester:

  • Pack your hospital bag to include your warm blankets and outfits for the baby, as well as anything to help make your hospital stay more comfortable. Think pyjamas, plenty of stretchy underwear, and maternity pads for post-birth.
  • Do your kick counts from about 28 weeks onwards. At the same time every day when your baby is most active (usually in the evening), put your feet up and time how long it takes to feel 10 distinct kicks. Make a note, and if anything feels different, speak to your midwife or doctor.
  • Attend antenatal classes and a hospital tour to find out more about your birth options, and learn some basic parenting skills. A hospital tour can help you to visualize your birth experience and might make you feel more prepared when it all kicks off! You don’t want to be getting lost mid-contraction!
  • Think about a birth plan. Pain relief, or au naturel? Music, or silence? Put some thought into how you would ideally like your birth to be, but try not to put too much pressure on it either. Remember, things might have to change during your labor to ensure a safe delivery.
  • Final blood tests and screenings like an iron level check and Group B Strep test might be offered in the third trimester.
  • Continue to avoid strenuous exercise, alcohol, smoking, and excessive caffeine intake. Just waiting a few more months until after your baby is born to have a glass of wine and snack on those forbidden pregnancy foods will help keep your baby healthy.
  • Prepare your baby essentials like installing your car seat for safe transport, and setting up a cot for them to sleep in when you get home.
  • Stock up the freezer with healthy and nutritious snacks and meals to keep you going through the crazy first days of parenthood. Your postpartum self will seriously thank you for it!

And that’s it! Whether you feel like it right now, or not, you are doing an amazing job, mama! Just keep going – and resting – for a few more weeks, then it’ll be time to meet your baby.