Mother hamsters do it. Mama cats do it. Expectant birds do it. And if you’re like many human moms-to-be — and some dads too! — you’re doing it as well: preparing your "nest" for your soon-to-arrive baby.

The nesting instinct during pregnancy can be just as powerful in humans as it is for our animal friends. It’s nature's way of getting you ready to nurture a child. 

What is nesting during pregnancy?

The definition of nesting, or the nesting instinct, is the burst of energy women often get in the last few weeks of pregnancy that inspires them to clean and organize the house in preparation for baby's arrival.

It’s productive too — driving many human moms-to-be to sweep out the garage, pair up all the stray socks that have wandered into the laundry room Bermuda Triangle, defrost the refrigerator and brighten the bathroom grout lines with a toothbrush.

But don't be upset if the nesting urge doesn't strike you at all. That's perfectly normal, too, and says nothing about the kind of mom or dad you'll be.

When does nesting start during pregnancy?

Nesting typically starts toward the end of the third trimester, around week 38 or 39 of pregnancy or a few weeks before your due date.

The increased adrenaline coursing through your system around this point in your pregnancy probably contributes to this final frenzy, but the emotional factors are just as strong. If the nesting instinct hits your nest right as you're preparing for childbirth, make the most of it now — before life becomes too hectic and finding a moment to shower will be challenging enough.

Safe things to do during nesting 

Stay sensible as the nesting instinct strikes. Don’t climb, overreach or lift anything too heavy. And avoid risky business such as standing on a ladder so you can scrub the bathroom ceiling. Skip harsh, toxic cleaners and still open windows and wear gloves when using mild ones.

Also be sure to take frequent breaks and snack often. You don't want to overdo it so close to labor and delivery — and let's face it, you'll need to save up some of that extra energy!

Here are a bunch of last-minute details that you can check off your list while you're in the throes of the nesting phase:

Restock your fridge

Out with the old, in with the new! As you prepare for birth, throw away any outdated items and shop for fresh ones.

Stock up on key essentials you’ll want to have on hand once the baby has arrived — milk, yogurt, cheese, prewashed salad greens, fruit and even a roasted chicken or two, which are perfect for meals, snacks and salads. And if baby doesn’t come this week, you can always restock again next week.

Pad your pantry

Stock up on staples like there’s no tomorrow. There will be a tomorrow, of course, but you won’t be able to spend it at the grocery store once baby’s around.

Easy does it when you’re a new mom, so line your shelves with every healthy convenience you can think of, from soups, which can stand in for lunch, to nuts, that perfect nutritious nibbler, particularly when teamed with dried fruit.

Other goods to get as you prepare for birth: whole grain crackers and cereal, canned beans, fruits and vegetables, pasta, brown rice and sauces.

Cook in quantity

If your nesting instinct is accompanied by the joy of cooking, indulge while you can. Cooking will almost certainly take a back seat once baby’s on board.

Make extra servings of your favorite frost-friendly foods — lasagna, mini-meatloaves, pancakes, bran muffins — and store in single-meal containers in the freezer. Mark them clearly so you won’t defrost a turkey burger when you’re in the market for banana bread.

You’ll be especially grateful to come face-to-freezer with homemade meals and snacks after surviving on hospital food or birthing center meals — and when pushing a button on the microwave is about as much effort as you can put into food prep.

Load your laundry

Feel like throwing in the towel? Go ahead — and while you're at it, toss in the duvet cover, pillow shams, throw rugs, guest bedroom sheets and anything else that doesn’t get washed regularly.

Once baby arrives, your washer and dryer will have to work hard enough just to keep up with the spit-up stains.

Deep clean

You know the spring cleaning that you’re always putting off until next spring? Whatever the season, now’s the time to tackle it while your nesting instinct is nice and strong.

Wipe down the windowsills and blinds (you may discover that they’re not gray after all!). Vacuum behind the sofa and under the sofa cushions — chances are you’ll make a quick buck or two while you’re at it, plus find the remote control you misplaced three months ago. Finally, get around to dusting the picture frames before that baby photo explosion makes the dusting more daunting.

Be sensible, though, in your quest for clean. Don’t push yourself if you’re pooped — push someone else, instead — and stay away from ladders or other precarious perches.

Outfit your baby

Still have some holes in the layette that your baby shower didn’t fill? Don’t overbuy while you prepare for birth, but make sure you’re well-stocked on those newborn essentials, including T-shirts, onesies, sweaters and booties. 

Outfit yourself

If you intend to breastfeed, buy nursing bras, nursing pads and nursing (or easy-to-open) shirts. And stock up on soft, breathable, oversized underwear you don’t like.

Why? You’ll need them extra big and comfy the first few weeks after the birth, and they might become stained with blood and discharge that may not wash away. Know you may have to throw them in the garbage about six weeks after your baby is born.

Be prepared

Babies need more than the clothes on their backs. They also need the diapers — and diaper rash ointment — on their backsides, along with a host of other crucial consumables.

Stock up also on baby soap, cotton pads, a rectal digital thermometer, rubbing alcohol, a nasal syringe, nail clippers, bottles, nipples and more. And for you, pick up plenty of super-absorbent maxi pads, Tucks medicated pads and ice packs — not the kinds of things you want to run out of in the middle of the night.

Get a jump start on birth announcements 

This way, they'll be ready to go as soon as you know the final baby stats. If you're mailing cards, address the envelopes now so they’re ready to be stuffed. Or compile a list of people to email — you can use it later to digitally send your birth announcement to the whole crew.