illustration of developing human baby at 18 weeks

18 weeks pregnant

For more information about week 18 in a twin or multiple pregnancy, tap here.

You may notice Baby turning it up a notch in terms of moving and grooving all around the womb. And you might also notice your appetite increasing. In week 18 lots of growth is happening with both you and your little one! 

How’s Baby?

Baby is getting bigger all the time and now weighs almost 8 ounces (223 grams). Your little one is punching, kicking, and thrashing about harder than ever in your womb — pretty soon, you may even be able to feel it! Baby’s facial features are continuing to develop, and your baby can now yawn, hiccup, and swallow. They’re beginning to develop a coating of myelin on their nerves, a substance that protects and facilitates the brain’s communication with the rest of the nervous system. Myelin is important for Baby’s brain development, and the best way to support this growth is to make sure you’re getting enough healthy fats, like DHA or Omega-3s.

What’s new with you?

By now, you’ve — hopefully! — noticed that the second trimester trades many of the debilitating side effects of the first trimester for more minor annoyances. You’ll probably notice your appetite growing to keep up with Baby’s growth.  As your little one starts storing fat to keep themselves warm after you give birth, it’s important to make sure that you’re eating a range of nutritious foods that will help you feel good and help your baby grow well. 

Another common finding at this time is low blood pressure, so it’s recommended that you don’t rise up from a seated or lying down position too quickly, as that might make you feel dizzy and light-headed. Experiencing lower blood pressure during parts of pregnancy is normal because your circulatory system expands a lot to meet the demands of pregnancy. This period of lower blood pressure generally lasts until around halfway through the second trimester and then will start to normalize. Until it does, support your body by drinking lots of water and don’t be afraid to slow down a little to give your body a chance to catch up. 

Reviewed by the Ovia Health Clinical Team
Read more
  • P Kristiansson, JX Wang. “Reproductive hormones and blood pressure during pregnancy.” Human Reproduction. Vol.16, No.1 oo. 13-17. Web. 2001.
  • F Witter, J Dipietro, K Costigan, P Nelson. “The relationship between hiccups and heart rate in the fetus.” Journal of Maternal-Fetal & Neonatal Medicine. Volume 20, Issue 4. Web. 2007.
  • WE Grever, FC Chiu, M Tricoche, WK Rashbaum, KM Weidenheim, WD Lyman. “Quantification of myelin basic protein in the human fetal spinal cord during the midtrimester of gestation.” Journal of Comparative Neurology. 376(2):306-14. Web. December 9, 1996. 
  • “Nutrition During Pregnancy: FAQ.” ACOG. American College of Obstetricians and Gynecologists. March 2021.
  • Mark A Curran, M.D. “Fetal Development.” March 31, 2019.

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