illustration of developing human baby at 13 weeks

13 weeks pregnant

For information about weeks 12 to 15 of a twin or multiple pregnancy, tap here.

Welcome to week 13! You’ve made it to the end of the first trimester! Second trimester, here you (and Baby) come!

How’s Baby?

Baby 2.5-3 inches long, the size of a jalapeno! And your little hot pepper is developing fingerprints now, and they'll be just as unique as them. Underneath your little one’s transparent skin, the bones that will one day help Baby stand up big and strong are also under construction and getting stronger, and their vocal cords are developing too.

Your baby’s lower body growth is also catching up with that of their head, making them look much more like a tiny human (and less like a tiny alien) all the time. However, until about the 36 week mark, Baby’s head will be about the same size as their abdomen. But when you think about how much their head dominated their little body just a few short weeks ago, it’s clear that your little one is making incredible growth!

What's new with you?

Congratulations, you’ve reached the last week of your first trimester! Many pregnant folks report the first trimester as being the most difficult, so if you were really struggling with morning sickness and fatigue, you can likely begin to find a bit of relief. The second trimester will introduce some new symptoms, and you might have also begun to experience more second trimester symptoms, like food cravings and aversions, swollen or tender breasts, and constipation.

One prevalent symptom you might notice in week 13? An increased sex drive. Unless your healthcare provider recommends pelvic rest (due to a condition like placenta previa), sex during pregnancy is totally normal and completely healthy right up until your water breaks, so don’t worry about any health complications for Baby. (After your water breaks is a different story, but you’ve got some time before you have to start thinking about that). If you’re in the mood, enjoy yourself.

You’ll also probably notice an increase in vaginal discharge, specifically leukorrhea, a milky discharge that protects the birth canal from infection. Unless the discharge comes with discomfort, rash, or a strong smell, it is nothing to worry about., You can keep your vulva and vagina healthy by wearing underwear and pants made from natural fibers and changing out of them as soon as they get wet or sweaty. Avoid douches and tampons, which can introduce bacteria into your vagina.

Reviewed by the Ovia Health Clinical Team
Read more
  • Sir John Dewhurst. Dewhurst's Textbook of Obstetrics and Gynaecology. 8th ed. Keith Edmonds. John Wiley and Sons Ltd, 2012. Print.
  • "Is sex safe during pregnancy." March of Dimes. March of Dimes. March 11, 2021. Web.
  • Mayo Clinic Staff. "First trimester pregnancy: what to expect." Mayo Clinic. Mayo Clinic. February 26, 2020. Web.
  • "Nutrition During Pregnancy: FAQ." ACOG. American College of Obstetricians and Gynecologists. June 2020. Web.
  • Mayo Clinic Staff. "Sex during pregnancy: What's OK, what's not." Mayo Clinic. Mayo Clinic. July 31, 2020. Web.
  • Mark A Curran, M.D. “Fetal Development.” March 31, 2019.
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