How Big Is My Baby in Pregnancy By Week?

Watching your baby grow through pregnancy is a fun way to pass the long nine months. Though sometimes it's really hard to translate all the inches, centimeters, crown to rump lengths etc. So here is a handy chart of common things to help you understand just how big your baby is now during your pregnancy.

Week 4: Mustard Seed

A single mustard seed with a needle

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At only four weeks past your last period, your baby is as big as a mustard seed. A pregnancy test would be positive starting this week of pregnancy. And if you had an ultrasound towards the end of the week you could see a gestational sac.

Week 5: Pomegranate Seed

Pomegranate seeds in spoon

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While a pomegranate seed doesn't seem to be very large, compared to week 4, your baby has grown a lot! The big news this week is that your baby's heart will begin to beat, but even with the most sensitive ultrasound, a transvaginal ultrasound, you typically can't see the heartbeat​ yet, but you can see a yolk sac.

Week 6: Black Eyed Pea

Black-eye beans

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This week the placenta really starts forming, but won't take full control of the pregnancy until the end of the first trimester. In bigger news, you can see arm and leg buds beginning

Week 7: Cranberry

Bowl of cranberries surrounded by cranberries on wooden table, elevated view

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It's hard to believe that something the size of a single cranberry can make you feel so tired or sick. Is your face breaking out too? Ultrasound will show your baby's heart beating this week and the newest development is rudimentary hands.

Week 8: Raspberry

fresh raspberries

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Your baby is moving on his or her own, but it's still too early for you to feel it in most cases. Soon you're even going to be able to count the finger and toe rays that your baby is busy growing this week. How are you feeling?

Week 9: Brussels Sprout

Christmas sprout

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Your baby now has testes or ovaries, depending on if the baby is a girl or a boy. While it will still be weeks before you could tell, it's nice to know there is something going on in there. Still lots of wiggling and moving. Your baby weighs a whole gram

Week 10: Pecan

Pecan nuts background

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Your baby's tail is gone! And the upper lip has formed. Other than that baby has been gaining weight and now weighs as much as four paper clips, that's four grams. That's about the size of a pecan.

Week 11: Date

High Angle View Of Dates In Bowl

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Your baby has a really big head, constituting about half his or her body size. This might look odd if you see it on ultrasound, but it will change as your baby grows. Though even at birth the head will be a large proportion of the baby's body. In other news, your baby has fingernails.

Week 12: Clementine

Two clementines in hand

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Your baby is as big as a clementine, also known as Cuties. Using a doppler, your doctor or midwife should be able to hear your cutie's heartbeat​ around this time. It's a great feeling, no? Your baby's brain is also finalizing structures that are present at birth, but there's a lot still to be done.

Week 13: Asian Pear

Asian Pears

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Your baby and the placenta weigh about an ounce each. So while your baby may be about the size of an Asian pear, but weight wise, it's a different feel. All 20 baby teeth have formed. But more importantly, you're in the second trimester!

Week 14: Apricot

Bowl of apricots on wood, partial view

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Did you know that your baby can practice breathing in the amniotic fluid? It's pretty amazing. He or she is busy moving around, but it's still a bit early to feel your baby. At about five inches long, your baby is about as big as this apricot.​

Week 15: Apple

Apple in hands on a wooden table

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So your baby is about as big as an apple, does that mean that you're nearly in maternity clothes? Interestingly enough, your baby's hair pattern is forming. All those scalp swirls and cowlicks...

Week 16: Starfruit

Star Fruit - Carambola (Averrhoa Carambola), Bali, Indonesia

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The starfruit is about the size of your baby this week, and starry-eyed might explain how you feel about finding out the sex of your baby. A few lucky parents will be able to tell this soon, but many will have to wait.

Week 17: Rutabaga

Swede

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Your baby now weighs more than the placenta. At birth, the baby will be seven times the weight of the average placenta. While no new structures have formed your baby can his or her thumb.​

Week 18: Artichoke

Studio shot of artichokes on table

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Your baby now has fingerprints developing which are unique to your baby, even if he or she is a twin. The bones are also continuing to harden or ossify. How are you feeling?

Week 19: Mango

Full Frame Shot Of Mangoes

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Your baby's permanent teeth are forming behind those baby teeth and their body is covered in a fine hair called lanugo. It probably feels like you have a large mango in your belly right now. Your baby weighs about as much as 227 paper clips or 8 ounces.

Week 20: Carrot

Harvested carrots lying in soil

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If you have a special ultrasound this week, you might find out that your baby is about as long as a carrot. You might also have the opportunity to find out if you're having a girl or a boy. Will you find out or be surprised?​

Week 24: Celery

Celery

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Your baby doesn't really stretch out much, which is hard to tell by the amount of movement that you're probably feeling. But if he or she were to stretch out, that would be about the length of the celery stalk. Think about that on the next trip down the grocery aisle.

Week 28: Cauliflower

Overhead view of cauliflower on wooden table

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Your curled up baby can flash his or her new eyelashes at you now. And at week 28, the baby is starting to curl up tightly and turn head down, the typical position for babies during birth. Imagine a big head of cauliflower all nestled deep in your pelvis.

Week 32: Pumpkin

Pumpkins in box

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If you feel like your baby is a small pumpkin in your belly, you'd be right! That heaviness you feel is fairly normal, and despite the feeling of heaviness, your baby isn't going to fall out. Pelvic tilts can be helpful at relieving that discomfort of late pregnancy.

Week 36: Pineapple

Pineapple

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Your baby is about as big as the body of a pineapple, all curled up now and getting ready for birth. While there aren't any new structures forming at this time, your baby's brain will see dramatic growth from now until around week 40. This growth helps them breathe and regulate their temperature after birth. So, this time is important.

Weeks 40+: Watermelon

Pregnant woman and her partner holding a watermelon

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Just remember, that babies, like watermelons, come in lots of shapes and sizes. The genetic makeup of you and your partner can have a lot to do with how big or small your baby is at birth. Though there aren't any good ways to tell how big your baby is before birth, not even ultrasound.​

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Article Sources
  • Heppard, M and Garite, T. Acute Obstetrics. Mosby Year Book. 1992.