Your baby measures 2.9 in (7.4 cm) from crown to rump and weighs 0.81 oz (23 g).

Sebastian Kaulitzki / Adobe Stock

Pregnancy Facts - Week 13

Aww yaaas! It's the last week of the first trimester. Like making it to the first fort in Oregon Trail, you've managed to avoided dysentery, fixed your wagon's broken axle and shot a few squirrels for dinner.

On second thought, it's nothing like Oregon Trail. You are however now a third of the way through pregnancy.


What's happening in week 13 of pregnancy

Morning sickness, tiredness and other negative pregnancy traits should subside now that your placenta has taken control of the hormone production form your own body.


Your increased energy will let you lead the life you left behind 3 months ago, except for your wardrobe. While it may not be visibly apparent to others just yet, you can probably feel it with the snugness of your pants and shirts. Your uterus has been growing in anticipation of the baby's growth, and at this point has reached a point where your body can no longer contain it without the formation of a baby bump begin.


Sleeping comfortably while pregnant


Sleeping on your side is highly recommended by doctors as it is the optimal position for blood flow from the placenta to the baby. If you're typically a back sleeper or a front sleeper, switching to your side may be uncomfortable at first. You may even find yourself waking up to find yourself in your preferred sleeping position.

A lot of moms-to-be have found sleeping with a body pillow, like a Snoogle, to be ultra comfy, a good way to regulate heat and to keep their body propped on its side through the night.

Determining your baby's sex

By now, you've probably had your first ultrasound. You've heard your baby's heartbeat and you've seen your baby on screen. It's really real! You've probably had a chance to see your baby's little face too. At week 13, it's too early to tell the sex of the baby from the ultrasound. Male baby parts are still too small to see regardless of dad's genetics. You'll know (if you choose to know) at your next ultrasound.


There are ways to identify the sex of the baby now if you must know now. Through a non-invasive blood test, where blood is drawn from mom, the sex of a baby can be determined with accuracy of about 95% for males and 99% for females. The old invasive way of doing it was amniocentesis, which takes an amniotic fluid sample from the amnitoic sac that the baby is floating in. There is an increased risks of miscarriage using this method, so it has been largely replaced by the blood test.

How big is your baby in week 13 of pregnancy

This week, your baby is 2.9 inches (7.4 centimeters) big and weighs only 0.81 ounces (23 grams).

Your baby's development in week 13 of pregnancy

Remember those ovaries your female baby started developing back in week 11? Well they're now full of eggs. Lots of them. About 7 million, right now. That's all that will ever be created. By the time she's born, this number will drop to 1 million, but that's more than enough to last her through her child bearing years. One of those eggs in there could one day be your grandchild. Your grandchild is already in your baby, in you, right now. Mind. Blown.


Remember those not ovaries your male baby were developing back in week 11? Nothing's changed. Still no ovaries developing.

What has changed regardless of your baby's sex is torso size. It's now grown to the point where it makes up only 2/3 of your baby's overall length. Not so baby T-Rex looking anymore now, huh?

Now back to Oregon Trail.


Come on, Nicole. Get your shit together.

My baby 2.9 in (7.4 cm) from crown to rump and weighs 0.81 oz (23 g)