Highlights this week
Baby development at 4 weeks
![embryo made up of hypoblast and epiblast embryo made up of hypoblast and epiblast](https://web.archive.org./web/20240131110405im_/https://assets.babycenter.com/ims/2018/06/pregnancy-week-4-yolk-sac_square.png)
Your baby is about the size of a poppy seed
![embryo in uterus at 4 weeks embryo in uterus at 4 weeks](https://web.archive.org./web/20240131110405im_/https://assets.babycenter.com/ims/2023/01/4-weeks-baby-in-body-jan-2023_square.png)
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ACOG. 2021. How your fetus grows during pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/womens-health/faqs/how-your-fetus-grows-during-pregnancyOpens a new window [Accessed December 2022]
Cleveland Clinic. 2022. Yolk Sac. https://my.clevelandclinic.org/health/body/22341-yolk-sacOpens a new window [Accessed December 2022]
FDA. 2019. Home use tests: Pregnancy. U.S. Food and Drug Administration. https://www.fda.gov/medical-devices/home-use-tests/pregnancyOpens a new window [Accessed December 2022]
Mayo Clinic. 2021. Fetal development: The 1st trimester. https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-care/art-20045302Opens a new window [Accessed December 2022]
Mayo Clinic. 2021. Symptoms of pregnancy: What happens first. https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/symptoms-of-pregnancy/art-20043853Opens a new window [Accessed December 2022]
MedlinePlus (ADAM). 2021. Fetal development. https://medlineplus.gov/ency/article/002398.htmOpens a new window [Accessed December 2022]
Merck Manual. 2022. Stages of Development of the Fetus. https://www.merckmanuals.com/home/women-s-health-issues/normal-pregnancy/stages-of-development-of-the-fetusOpens a new window [Accessed December 2022]
NIH. 2017. What are some common signs of pregnancy? National Institute of Child Health and Human Development, National Institutes of Health. https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo/signsOpens a new window [Accessed December 2022]