40 Week Ultrasound: Key Facts

In all likelihood, you’re not going to be having a 40-week ultrasound while you're actually giving birth.

So, this one goes out to the mamas whose little ones are so comfy in there they’ve decided to stick around in that uterus a little longer.

First things first, if you’re past your due date, it doesn’t mean that anything is wrong with your baby.

They may just be on the last chapter of a book they can’t put it down. Who knows?

So, rather than worrying, get back to that super-excited feeling when you were counting the days (280 to be exact) from your last period in order to get a due date estimate.

Remember when it felt oh-so-far away? Well, wait no longer, mama!

You’re 40 weeks pregnant. Baby is on their way, even if they’re dawdling a bit. They’re actually (almost) here!

While everyone’s situation is different, here’s what could be in store for you.

In this article: 📝

What happens if you reach 40 weeks pregnant?

At 40 weeks pregnant, your healthcare practitioner will do a biophysical profile.

Quite simply, they’re checking to see if your baby’s doing okay in there, how badly they want out, and if their exit strategy will run smoothly.

Once they have that intel, they’ll guide you as to the next steps.

There are usually two main components to the 40-week pregnancy appointment: 1) an ultrasound and 2) what’s called a non-stress test.

What should I expect at my 40-week ultrasound?

Because you’re full term at this point, your doctor is checking to see that your baby is in good shape in there.

The ultrasound will monitor the status of the amniotic fluid to check that your baby is getting the nourishment they need.

They’ll look to see how strong those muscles are and how breathing is going.

They’ll also do some measuring. At this point, your baby is about 7.6 lbs—and that, if you must know, is about four-fifths as heavy as a cat.

And if you’re asking, how accurate is ultrasound weight at 40 weeks? The answer is the most accurate reading you will get during your pregnancy. Nice.

40-week ultrasound pictures

There are two types you can opt for:

• 40 week 3D ultrasound: Think photograph.
• 40 week 4D ultrasound: Think video—and perhaps the last moving picture of your little one while they’re still on the inside.

(It's likely a bit too late for a 5D ultrasound at 40 weeks, since baby's not got a whole lot of room in there.)

What is a non-stress test in pregnancy

Your baby is about to go on a pretty wild adventure.

The non-stress test (NST), also referred to as the contraction test, assesses how they’re doing and how they’ll manage the crazy journey ahead of them.

Essentially, it looks to see how your baby’s heart accelerates and decelerates with movement and, in turn, how well they’ll respond to contractions.

If you’re worried about this test, don’t be. The NST is:

• Painless
• Non-invasive (they’ll just hook your belly up to some monitors)
• Relatively quick (about half an hour)
  Hot tip: Pee beforehand. It’ll make the whole experience a lot better for you. As 30 minutes with a pregnancy bladder can be, well, we don’t have to tell you.

You may have a series of NSTs if your baby is taking their time to arrive.

In some cases, the doctor will order these before you’ve come to term.

40 weeks pregnant: how to bring on labor?

If you’ve hit 40 weeks pregnant and you’re like, “C’mon! I’ve had enough now,” there are some steps to take to coax your baby out of their happy place.

Your doc might want to induce labor medically if they’re concerned about anything.

If they’re not concerned, chances are they’ll wait until your little one is good and ready to make their appearance on the world stage.

A relaxed walk can be a great way to encourage labor. Another? Have sex.

We’re not kidding.

Not only can it stimulate contractions, but it can also be a crazily awesome bonding experience for you and your partner. Why not?

Okay. It’s almost time. Deep breaths. You’ve got this.