The fourth trimester: the very term sounds counterintuitive. "Tri" means three. A tricycle has three wheels. King Triton's trident has three prongs. A school year is divided into three trimesters. You're pregnant for nine months (give or take), and that gestation period is conveniently divided into three, three-month trimesters. So what's this about a fourth? I'm not keeping that baby in there any longer than I have to! Well, no. The fourth trimester refers to your baby's first three months of life outside the womb. Turns out, there are many reasons you should absolutely call it the fourth trimester.
It's strange. There's so much information about pregnancy out there on the internet and online forums and books and soon-to-be mom groups. If you're anything like me, you were reading about what was happening in your body, checking your "what size fruit is baby" chart, and referring to your pregnancy app every week. However, there's not a ton of information on the fourth trimester. In fact, I only knew the "fourth trimester" was a thing after reading The Happiest Baby on the Block, by Dr. Harvey Karp. Dr. Karp's "5 S's" of soothing and colic philosophy are based on the idea that the fourth trimester isn't only real, but that newborns need a fourth trimester.
It might sound silly, but I found that thinking of the months that followed my baby's birth to be part of an "extended pregnancy" helped me better understand my daughter and meet her needs more effectively. It also helped me forgive myself and my still-healing body, as well as my squalling baby, to know that what we were going through was completely and physiologically normal.
Human Babies Are Born Too Soon
What's the thing that makes us humans so darn special? Our big old brains! The problem is: women's birth canals? Not so big. Thanks to evolution, a few things happened to make sure babies didn't get stuck in the birth canal (and moms didn't die in the process).
First, a newborn's compressible brain accommodates only the most basic skills and reflexes. It's small and basic so it can fit, although another theory is that because humans are such social animals, we need more of a blank slate to soak up all our needed cultural information. Second, human mothers expel their babies from their bodies early in order to improve survival rates.
In essence, the first three months of life are the "missing" fourth trimester.
Your Baby Craves Womb-Like Conditions
There's a reason your crying baby is immediately calmed by the sound of the vacuum cleaner. White noise machines, a running washing machine, the car; they all mimic the shooshing sound of a uterine environment. Which, incidentally, is why we shush crying babies.
Humans have been swaddling babies for thousands of years. Why does it work? It's cuddly and cozy, just like your womb. Basically, your baby still wants to be in your body. These techniques make them feel like they are.
Your Baby Wants To Be Held And Carried. Constantly.
Have you noticed that a newborn baby is very reluctant to be put down? Well, think about it. They've been carried around for 40 weeks (give or take), and by all rights, they should get more time. They like to be rocked, swung, held, and carried in a sling because those actions mirror the swinging sensation they felt in utero.
Newborns Are Immature
I'm not talking about immature as in thinking butts are funny. That comes later. I mean they're physically underdeveloped. Have you ever seen another newborn mammal? I watched a giraffe being born. That thing was 5'7" and immediately stood up. Our babies are terrifyingly small, helpless, and floppy. But we'd never get them out vaginally if they weren't.
Your Body Is Recovering From Trauma
Everyone knows that pregnancy can be the pits. It absolutely wreaks havoc on your body. There's nausea, backache, heart burn, round ligament pain, swelling, fatigue, and hemorrhoids, to name a few. Everyone knows labor and delivery are no picnic.
However, postpartum recovery doesn't get as much press. Calling it the fourth trimester acknowledges what your postpartum body is going through, from cramps to soreness to bleeding.
Babies Are Vulnerable
Because babies are evicted before they're really "ready," they come out utterly defenseless. Infants need a lot of protection. We don't generally have to protect them from predators (although I hear grizzly bears are making a comeback among the elementary set), but we do have to keep them safe from inclement weather, disease, infection, falls, etc. It's a long time before they're independent, but those initial three months deserve a designation.
It Honors The Work You're Doing
During the three months following your baby's debut, you will get very little (if any) sleep, feed them every three hours (at least), and hold and soothe them endlessly. You will do all this while recuperating from a birth, and for many moms, from major surgery. Many of you will soon return to work.
There's never another time like this during your child's life. So me? I'm going to call 'em like I see 'em. The fourth trimester? Yeah, it's a thing. Definitely a thing.