Sumber:

• https://www.bellybelly.com.au/pregnancy/what-is-a-placenta/
• https://flo.health/pregnancy/giving-birth/labor-and-delivery/what-is-a-placenta
• https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/placenta/art-20044425
• https://www.nhs.uk/common-health-questions/pregnancy/what-is-the-placenta/