What Happens in the ‘4th Trimester’ (and Is It a Real Thing)?

Just when you thought you'd reached the finish line of pregnancy, you discover there’s one more "trimester" to get through.

We’re talking about the so-called "4^th trimester" — that hazy period where you’re recovering from pregnancy and delivery while simultaneously learning how to be a mom as your baby adjusts to life outside the womb. 

Here’s a look at what you and your little one may be going through during the 4th trimester, how to feel your best and when life will start to look a little more normal again.

What is the 4^th trimester?

The fourth trimester (more commonly written as the "4^th trimester") describes the postpartum period starting from your baby's birthday until he turns 3 months old.

The term is believed to have been coined by Dr. Harvey Karp, a pediatrician who theorized that human babies are born about three months too early.

After those nine months of pregnancy have passed, the thinking goes, fetuses' brains are so big that babies may not fit through the birth canal if they stuck around in the womb much longer. Even so, they’re still not quite mature enough to leave their cozy, cushy space — and it takes about 12 weeks for them to adjust to life on the outside.

That accounts for the major change your little one goes through in a relatively short time — from sleepy, sometimes fussy, scrunched-up newborn to (hopefully) calmer, happier, more alert 3-month-old baby. By 12 weeks, your little one can likely hold his head up to some degree and is becoming more interested in and aware of the world around him. The 4^th trimester is a period of significant physical, mental and emotional development for your baby.

But it’s a time of change for new moms too. As your body readjusts to no longer being pregnant, you’re learning how to care for a new baby — and navigating the major life changes that come along with it.

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What is happening during the 4^th trimester?

Both you and your baby will go through major transformations in those first three months after birth, and it can sometimes feel pretty overwhelming.

Understanding this time period and what you can expect can help you be more prepared, recover faster and be good to yourself in the process. Here's what happens during the 4th trimester:

Postpartum changes moms experience during the 4^th trimester

Especially in the early weeks after your baby arrives, your body is recovering from giving birth. Your hormones are in flux, your organs are shifting back to their former positions and your breast milk is coming in.

At the same time, you’re experiencing normal postpartum bleeding and dealing with the discomfort of a healing perineal area and/or a C-section scar. 

While many women are considered to have physically recovered from birth after six weeks, that doesn’t mean your body will feel or look just like it did before you got pregnant.

After all, it took you nine months to grow your baby. You can expect it to take at least that long for your body to go back to “normal.” And if you’re breastfeeding, you might not feel completely back to your old self (or at least, something like it) until you’ve weaned.

Feeling like your body isn’t your own can be challenging in and of itself. On top of that, you’re dealing with the fatigue that comes with caring for a newborn and the normal emotional ups and downs that accompany settling into life with your new baby.

Things also might not look exactly how you pictured they would while you were pregnant, and you might be missing aspects of your pre-mom life. It can be a lot to take in all at once! Just remember that you're not alone in whatever you may be feeling.

Baby’s development during the 4^th trimester

While you’re experiencing a lot of new things during those first three months, everything is new for your little one. And after nine months in a warm, watery womb, adapting to life on the outside can be a little challenging, to say the least.

In those early days, it might seem like your newborn hasn’t quite gotten the memo that he's entered the real world. He’s still often curled up in the fetal position, his movements are jerky, and he can easily become overstimulated and fussy.

He also may seem to be mixing up day and night, demand to be fed round-the-clock and snooze at random intervals. At this point, all he really wants to do is eat, sleep, go through diapers and be held!

But he won’t stay like this for too long. As your baby grows (as much as a couple of pounds in weight and 1 ½ inches in length by the third or fourth month), he’ll go through other big physical changes too. His arms, legs, hands and feet will start to unfurl, and as baby's muscles develop, those little movements will become more deliberate.

Your baby will also gradually gain control of that big, heavy head and start to lift it higher and higher. By 3 months, your little one will likely be looking around while leaning on his forearms during tummy time — and not long after that, may even begin to push up.

As baby's vision improves and the capacity for interaction grows, that little personality will start to take shape too. Over the course of the 4^th trimester, your sweetie will go from newborn who gazes through cloudy eyes at you to a more bubbly infant who delights in playing, imitating some of your movements and facial expressions, and even smiling.  

And if those sleepless nights and seemingly non-stop feedings have you dreaming about getting in even a few hours of uninterrupted shut-eye, take heart. By the end of the 4^th trimester, your baby will be on the way to a fairly predictable eating routine and something akin to a more consistent sleep schedule.

Tips for coping with some of the biggest 4^th trimester challenges

These foggy, whirlwind days won’t last forever. But in the meantime, here are some strategies to help you make it through.  

Ask for help.

Don’t feel like you have to do everything yourself. Let your partner or a close friend or relative help take care of the baby. 

Even if you’re breastfeeding, they can take your little bundle at other times so you can sleep, as well as handle diaper and bathtime if you're comfortable delegating those baby care duties.

When someone comes to visit, give them something to do instead of feeling like you need to play host. Ask for them to bring groceries or a meal, do a load of laundry, empty the dishwasher or just hold the baby so you can take a shower.

Know that it’s normal to not feel normal.

Intense mood swings and periods of weepiness are so normal after having a baby that they even have their own name: the baby blues. Pair that with the sleep deprivation, and you’ve got the potential for a serious storm of emotions.

Don’t beat yourself up for feeling this way, or for worrying that you aren’t doing enough. If you’ve managed to get some rest, eat something and care for your baby, you’ve ticked off all the important to-do's.

That said, while feeling more emotional during the weeks right after birth is common, feeling chronically sad, depressed or overly anxious, or having thoughts of harming yourself or your baby can be signs of postpartum depression (PPD) or postpartum anxiety (PPA).

That doesn’t mean you’re losing your mind, are a bad mom or have done anything wrong — postpartum mental health issues like PPD are never your fault. But they are treatable, so if you think you may be suffering from PPD or another condition, reach out to your doctor for help.

Take care of yourself.

Covering the basics will go a long way towards helping you feel strong and energized.

Try to eat healthy foods like fruits, veggies, lean proteins and whole grains, and limit the sugary snacks. Drink plenty of water. Get out of the house when you can, even if it’s just taking the baby for a walk around the block.

When your little bean sleeps, resist the urge to get things done around the house and try to get some shut-eye yourself.

If you aren’t getting the rest you need to function, ask your partner, family and/or friends for more support. Or if you're ready, try finding a babysitter you trust. Maybe someone can come over once or twice a week for a little while so you can nap. Ask your partner to take over a nighttime or early-morning feeding if you've introduced bottles.  

Find a group for new moms. 

Even with a supportive partner, family members and friends, you still might feel like you’re going through it all alone sometimes. Talking with other moms gives you a chance to share your feelings with women who understand exactly how you feel because they’re in the thick of it too.

But where do you start when you're trying to make new mom friends? Ask your pediatrician or OB/GYN to recommend support groups, find out about local parent Facebook groups, or check bulletin boards at the grocery store, library or community center in your area. If and when your little one starts day care, that's a good way to meet other parents with little ones the same age too.

You can also just strike up a conversation with another mom when you see one out in the wild, like in your neighborhood or at a nearby playground. Chances are, she’s as eager to talk as you.  

Go to your postpartum appointments.

The American College of Obstetricians and Gynecologists (ACOG) recommends that new moms have their first postpartum checkup with their OB/GYNs or midwives within three weeks of giving birth and receive ongoing care as needed, plus schedule a comprehensive exam within 12 weeks of delivery.

These visits are an opportunity to talk about your concerns or challenges — both physical and emotional — and find ways to help you feel your best. 

When does the 4^th trimester end?

The 4th trimester ends around three months postpartum. Does that mean that you’ll look and feel exactly like you did before you got pregnant — and that caring for your baby will be a breeze 24/7? 

Probably not. Adjusting to life with a new baby, whether it's your first, second, third or something else, is a gradual transition that will likely continue throughout that first year and beyond. And though your 3-month-old baby is vastly different than his newborn self, it goes without saying that he’s got a whole lot of growing and developing still to come!

Plus things never quite "go back to the way they were" before you gave birth — parenthood changes you! — but you can look forward to feeling more like your old self in time. By 12 weeks after baby's arrival, you can expect to feel much more physically and emotionally comfortable than you did initially. Your baby will likely be more fun and interactive, and at least bit less fussy (fingers crossed) too.