Twin pregnancy types
Content provided by Healthwise
Twin pregnancy types
Identical twins come from a single egg that has been fertilized by one sperm. For unknown reasons, the fertilized egg splits into two embryos during the first stage of development. In the mother's womb (uterus), most identical twins share the same placenta. (They get oxygen and nutrients from the mother and get rid of wastes through the placenta.) But they usually grow within separate amniotic sacs. In rare cases, identical twins share one amniotic sac.
Fraternal twins develop when two eggs are fertilized by two separate sperms. The fetuses have separate placentas and amniotic sacs.
Credits
| Primary Medical Reviewer | Adam Husney, MD - Family Medicine |
| Specialist Medical Reviewer | Gregory A L Davies, MD, FRCSC, FACOG - Maternal-Fetal Medicine |
| Last Updated | July 24, 2007 |
| Last updated: | July 24, 2007 |
|---|---|
| Reviewed By: | Adam Husney, MD - Family Medicine, Gregory A L Davies, MD, FRCSC, FACOG - Maternal-Fetal Medicine |
© 1995-2007, Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
This information is not intended to replace the advice of a doctor. By using AOL Body, you indicate that you have read, understood, and agreed to our Terms of Service, and AOL Body Advertising Policy. Read more about our content partners.
Search
Where Does it Hurt?
If you're experiencing aches and pains we can help you find answers. Find out what your symptoms mean for your health.
