The first three months after babies are born are often referred to as “the fourth trimester.” It’s because human newborns are so much more dependent on their parents and vulnerable than other newborn mammals. While some mammals can practically walk at birth, I remember reading that human babies intuitively know only how to suck, swallow and breathe. They even have problems breathing consistently sometimes. I believe this has something to do with evolution and since we walk upright, we have evolved to a gestation period of around 40 weeks so that we can safely birth our babies’ big heads and big brains. So, the infant human baby is still developing during that fourth trimester in a way that is similar to how other mammals develop while still in the womb.
In learning about the fourth trimester, I remember feeling relieved that parents shouldn’t expect babies under three months to be on a schedule or to sleep through the night. We need only feed them on demand and let them be infants.
Adelaide turned nine months on April 28. Tim pointed out that she has now had equal amounts of time growing both inside and outside of me. “Nine months in, nine months out” as my friend Jennifer put it.
At her nine-month appointment on Tuesday, Adelaide weighed in at 19 lbs 11 oz (50th percentile) and 28 1/2 inches tall (75th percentile). She’s leveled off a bit on the weight chart, but our pediatrician said that was normal at nine months. Adelaide still has no teeth. My friend Brooke’s son is a month younger than Adelaide and he’s had six teeth for weeks. No teeth and six teeth are both totally normal.
We also talked to the pediatrician about food. Although Adelaide has loved all the solids we’ve given her, we’ve been slow to introduce them. Knowing she’s getting all her necessary nutrients from my breastmilk, we’ve just been experimenting with solids at night and on the weekends. And we haven’t even been doing that consistently every night. But that’s all starting to change. Our pediatrician suggested that we start sending food to daycare and giving Adelaide three “meals” a day. While she doesn’t really “need” solids as a form of nutrients right now, she will start to need nutrients from solids at around a year old. She’ll be twelve months with just a blink of an eye, so we’re going to step-up her solids intake. We’ve also started letting her play with a sippie cup and drinking from a straw is next.
We have a real crawler on our hands now (no more just hacking it with an army crawl). She has pulled herself up to standing in her crib (just once that we’ve seen – but hey, she can do it). She likes to clap and is happy and social, smiling at strangers and letting everyone hold her. People ask us all the time if she is always that smiley (answer: yes, usually), and when we pick her up from daycare they always say she just smiled and laughed all day.
Someone recently told me that it’s around nine months when babies really start to develop personality. Nine months in, nine months out. Six months post the “fourth trimester.” And so much to look forward to.