We’re in deep. Baby #2. Week #6.

I’m of the belief that the real shaping of your child’s personality, intelligence, and behavior – the “hard part” – really doesn’t begin until about six months. You can let them watch “Scarface” naked at 2 a.m. while listening to gangster rap without doing any permanent damage. The “fourth trimester” is the time in a baby’s life from birth to three months and it is all about physical endurance – yours and theirs. So don’t stress about their minds and emotions quite yet. You have enough to do keeping your precious meatloaf happy and alive and taking care of something equally as important: You.

Dr. Harvey Karp has a wonderful video called “The Happiest Baby on the Block,” in which he demonstrates a weird-looking but very effective method of calming a cranky newborn, which basically involves wrapping him up tightly and jiggling him on his side while saying, “Shhhh!!!” loudly in his ear. It works. Most of the time. For me, however, the more important takeaway from the video is the “why” behind the technique, and the concept of the fourth trimester.

Most animals do not experience this unique aspect of human life, because they are born much more physically advanced than humans. Take for example a horse, who is up and running on day one, because the ability to walk and run is important for its survival. The human brain, on the other hand, is our most important tool for survival, and we therefore have proportionally big heads. If newborn humans were to be born as physically advanced as a newborn horse, human mothers would be birthing 20-pound babies. The size that human babies come out is the absolute maximum it can be, or their heads would not fit through the exit. So, due to their oversized heads, human babies come out “early,” and are therefore not really ready to be out in the world yet. They should still be in the womb – hence the “fourth trimester.”

There’s a reason they look like aliens. They don’t belong here.

You can read lots of articles detailing techniques to utilize during the first three months in an attempt to recreate the familiar womb environment for your baby. But this article isn’t about the baby. It’s about you. Let’s talk about you.

Bottom line, you have one job for the first 90 days of parenthood: Keep baby alive. That may sound overly simple, complex, or dramatic depending on your perspective, but nevertheless, it’s true. You really don’t need to overthink her physical, mental, or emotional well-being during this time. That will come later when she’s four and throws her string beans across the room because she didn’t get invited to the 13-year-old neighbor’s birthday party.

The good news here is that the baby is on your side in this task. He’s a meatloaf, but a meatloaf with an inclination to stick around, so it’s not like you’ll be fighting an uphill battle of survival with an unwilling meatloaf. He really only needs two things in order to survive: food and sleep. And he has built in mechanisms to ensure he gets these things: A loud alarm will sound from the baby when food is needed, and the automatic power-down function will engage when sleep is required. So, your job is simple, but not easy. Keeping yourself rested, fed, and sane while doing it is a different challenge entirely. I’ll share some things we’ve done, bought, and learned that have allowed us to remain relatively functional through one and a half fourth trimesters. Functional enough for me to write this article anyway.

Buy baby buy

I’m still astounded when I look around the house and in the car at all the stuff that a newborn baby “requires.” At one point, however, I realized the two things he truly requires – milk and sleep – you can’t buy at Buy Buy Baby. All this stuff wasn’t really for him. It was for us. Getting the right stuff is essential to your surviving the fourth trimester.

1 | Changing table

These are built tall so you can change your baby’s diaper without bending down, and after a few hundred changes, you (and your back) will understand why this is important. Changing tables also have storage drawers that fit pretty much all the baby’s clothes, blankets, etc., as well as a ready supply if diapers, wipes, and changing paraphernalia. It’s all in one place, so you don’t have to think about it, or look for it. Baby doesn’t care where you change him, or often even if you change him at all. The changing table is for you.

2 | Stroller

So you don’t have to carry the baby and all her stuff around. The stroller is a baby, baby supplies, purse, and grocery holder all in one. Don’t leave home without it.

3 | Swaddle

Funny thing about newborns: They can’t control their parts. It’s all new to them. Their heads flop around like tennis balls on noodles. They smack themselves in the face and cry. Their own farts scare them. They are small living versions of those inflatable display beings outside used car dealers. Swaddles are like little baby straitjackets that stop them from swatting or disturbing themselves inadvertently. The thing is, the tightness of the swaddle recreates the familiar cramped quarters of the womb, so they dig it. They sleep better, so you sleep better. I imagine that throughout history millions of babies have slept badly in their fourth trimester, and have not only survived, but thrived. But trust me, do yourself a favor – swaddle. And sleep.

Note: Get a swaddle with Velcro or a zipper. They are easier to operate in a foggy 3 a.m daze than the ones the hospital nurses make from cloth and magic, and babies can’t do their Houdini-esque escapes from them.

4 | Bassinet

We use ours exclusively at night. When baby goes into bassinet and lights go out, it’s night, and night means sleep. Both kids seemed to “get it.” Baby #2, who only sleeps for two hour stretches during the day, is going down for five hours at night, and baby #1 was going for six hours a night at three weeks! And the longer baby sleeps, the longer you sleep.

We also bought a wooden rocker thing for $50 to put the bassinet on. It elevates it, which is nice, and you can rock the baby in it until she falls asleep.

Note: There are mixed schools of thought as to whether newborns need to be woken to eat or not. Follow your doctor’s advice. A friend’s 70-something-year-old pediatrician did say that he has yet to hear of a case in which a baby slept itself into starvation. We let our newborn sleep crazy long at night and she was off the growth charts until she was six.

5 | Bottles

We bought new “recommended” bottles that only served to make baby mad and took baby forever to empty. We now use six-year-old bottles that baby drain happily in minutes, like his big sister did. Happily fed babies are much easier to deal with than grumpy, hungry ones. Get a bottle that makes baby happy. For your sake.

6 | Monitors

We’ve developed a schedule/routine in that after what we determine is baby’s “last” feeding for the day, he goes “to bed.” Sometimes depending on how feedings shake out, that is at 10 p.m., and we join him, but sometimes it’s 8 p.m. and we have two hours of “free time” before joining him – all due to the presence of a baby monitor.

7 | Seats

In the daytime hours of the fourth trimester and beyond, there are basically two places baby will be: in your arms, or in some kind of seat. This may sound obvious or trivial to non-parents who have never had to find a safe place to put a human for 12 to 14 hours a day, for 12 months. There are so many varieties, and babies have different tastes in seating, none of which you will know until after you have bought the seat.

My advice is to buy a few and experiment. Our first one loved her high-tech swing that played lullabies and emitted a sparkly display of stars. The new one hates it, and prefers the old spat-up-on brown and pink cloth stationary rocky chair. It’s worth the effort, because if you don’t find a seat that baby likes, you will become his favorite seat. Babies often seem happiest the more completely they can incapacitate you, so get them used to sitting somewhere besides in your arms as early and often as possible, so you can do fun stuff. Like pee. And bathe. And eat.

My biggest piece of advice for surviving the fourth trimester: Get stuff. It helps. A lot. Trust me. Yes, having and using all this stuff for only three to six months seems crazy. Do it. If guilt is an issue, pass it on when you are done with it. This is not the time to be cheap or luddite or earthy or brave or paleo-minimalist. Buy stuff. Your survival depends on it.

If cost is an issue be smart about how you acquire stuff. We saved a lot of our daughter’s things in the attic for six years till we had our son, and he certainly doesn’t mind the pink boppies and burp cloths. We’ve had so many clothes given to us from families who have outgrown them, we’ve barely bought any. When we were told that our old car seat had “expired,” we erred on the side of safety and sprang for a new one, but when we were told that our old $700 stroller had similarly “expired,” I called bullshit and stuck with the old one.

The fourth trimester can be tough, so be prepared, and remember that in this time your meatloaf will smile at you for the first time, and all the sleepless nights, spit up, and seat drama will be worth it.