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13 weeks pregnant is a true milestone for many pregnant moms. Miscarriage risk is going down, and the first trimester is coming to an end. Already one-third of the pregnancy is done. Wow!

You have probably also started to put on some weight, and there is more to come.

This article will cover your baby’s development, how big your baby is, what month you are actually in, pregnancy symptoms, and what’s happening with your belly and body, Mom.

Week 12 | Week 14

13 weeks pregnantPin

What to Expect When 13 Weeks Pregnant

How Many Months is 13 Weeks Pregnant?

Your baby’s fetal age is now 11 weeks, and you are going through the last week of the first trimester.

Now you are 1/3 through your pregnancy.

This is the last week of being 2 months pregnant. Beginning of next week, you will have completed 3 pregnancy months, and hence you are then 3 months pregnant (entering the fourth month of pregnancy). It goes quite fast, don’t you think? :-)

Your Baby’s Development

What Does My Baby Look Like when 13 Weeks Pregnant?

what does my baby look like when 13 weeks pregnantPin

As you can see in the picture above, a 13 weeks fetus looks very human. Look at how developed the toes and fingers are!

The head is still out of proportion – way too big compared to a newborn baby. At this point, the head is about half of the baby’s crown to rump length. When born, the head will be about a third of this length.

Here is a wonderful, detailed video of an ultrasound scan in week 13.

fetal ultrasound of 12 weeks baby boy moving (3D)

How Big is My Baby in Week 13?

baby fruit size pregnancy week 13 lemonPin
Your baby is now almost 3 inches in length (7.6 cm) and weighs about 0.81 of an ounce (25 grams).

It is comparable to a lemon in length but looks almost like a miniature version of a newborn baby.

You’ll find a handy (and cute!) chart for baby size by pregnancy week here, with more detailed measures and fruit comparisons.

Fetal Development When 13 Weeks Pregnant

Here’s what your baby is up to this week:

  • Fine hairs are growing on your baby’s body, and even eyebrows are growing.
  • The intestines are now moving further into the body while the pancreas is producing insulin that is necessary for regulating sugar levels in the body later on in life.
  • The placenta that is entirely functional now supplies the baby with oxygen, vitamins, minerals, fats, and proteins. Removed carbon dioxide and waste materials are filtered through the placental tissues.
  • The placenta is still quite large in size compared to your baby and allows everything that the mother experiences to be for the baby as well. At least the good parts. The placenta is very effective in protecting the baby from immune attacks and some harmful substances (but not all, like alcohol, for example.)
  • Few congenital birth defects develop after the 3rd month of pregnancy. For example, spina bifida and cleft palate both develop as early as the fifth or sixth week of pregnancy.

Mom’s Body when 13 Weeks Pregnant

Your Belly and Uterus Size in Week 13

13 weeks pregnant bellyPin

Just like last week, your uterus is about the size of a grapefruit.

During this week or the next, the uterus will be big enough to reach above your pelvic bone. This means that if you lay down on your back and relax, you might actually be able to feel the top of the uterus by pressing lightly just above the pelvic bone.

The 2nd trimester is sometimes referred to as the “honeymoon stage” since many symptoms from the pregnancy will ease up, and energy levels return, along with libido for some women.

Some mothers-to-be will find themselves glowing due to the increase in circulation of their body that gives them that attractive pregnancy look.

Although your “baby belly” isn’t that large or getting in the way yet, you will soon see exactly how much the muscles can stretch to accommodate your growing baby.

If you still have a waist, it will soon be gone. Very soon, you will not fit into anything but your new, sassy maternity clothes

You have definitely increased in weight. Learn about weight gain during pregnancy here.

Pregnancy Symptoms in Week 13

You may start experiencing some muscle aching or cramping due to your abdominal muscles stretching in order to prepare your body for your growing baby. This is referred to as round ligament pain.

This can be anywhere from a dull ache in your abdomen to sharp but brief pain and can be relieved by taking it easy and making sure to change your position when sitting or sleeping.

For some women, their breasts are changing in shape and beginning to produce colostrum, which is the nutrient-rich fluid that will feed your baby in the first few days after birth before your regular breast milk is produced.

You may still feel some discomfort in your breasts and even lumpiness from the developing mammary glands, but that will subside periodically as well.

You may find an increase in heartburn due to the stomach acids traveling back up your food pipe. Help alleviate these symptoms by eating smaller, more frequent meals that include a balanced diet rather than greasy, fried foods.

Which pregnancy body changes are you experiencing? Vote in our pregnancy body changes poll and compare with other moms.

Things to do and buy this week

Week 13 Pregnancy Video

13 Weeks Pregnant: Watch the Growth of Your Baby

Diary of a Daughter

What’s it really like being 13 weeks pregnant…? Here’s a true diary from a 13 weeks pregnant mom (Me..!)

What a week! First, I experienced some spotting and was totally freaked out. Had an emergency ultrasound. My baby was fine! Three days later, it was time for my nuchal fold screening test. The risk for Down’s syndrome is very low – 1 in over 3000. Wonderful!

Are you also 13 weeks pregnant? Please share your experiences and thoughts by leaving a comment below!

Read Next


Mayo Clinic, Mayo Clinic Guide to a Healthy Pregnancy
Joanne Stone MD and Keith Eddleman MD, The Pregnancy Bible: Your Complete Guide to Pregnancy and Early Parenthood
Nilsson, L; Hamberger, L. A Child Is Born
Soderberg, L., Mammapraktika. B Wahlstroms.

Image: Image of 13 weeks belly by 4Neus

Week 12 | Week 14

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This Post Has 2 Comments

  1. Pamela

    My story is a little bit different because I tested few times but they came out negative I became so sad en depressed
    So I decided to go to the hospital but still the blood and urine tests came out negative went to the scan and they also so nothing but I was feeling really sick but they told me nothing was wrong with me but I knew I was not okay .So wen I left the hospital I decided to talk to my boyfriend about it he was so supportive always and was always there to support in anything ..so he decided for us to wait for the months to increase to ne able to get proper results the next time we go back to the hospital because I was sure I was pregnant and he believed me even though the tests all came out negative….So am currently 13weeks pregnant because I even have a bump ..gained alot of weight lately…so fingers crossed all hoping for the best results in March when we decided to go back to the hospital..God first in everything…So if u r out there have faith and hope …God is always there for us..We just have to have faith ….Thanks

    1. Paula @ EasyBabyLife

      Thanks for sharing, Pamela. I really wish you good luck!