Maternity Nursing Q 87

---

When describing dizygotic twins to a couple, on which of the following would the nurse base the explanation?

  

     A. Two ova fertilized by separate sperm.

     B. Sharing of a common placenta.

     C. Each ova with the same genotype.

     D. Sharing of a common chorion.

    

    

Correct Answer: A. Two ova fertilized by separate sperm

---

Dizygotic (fraternal) twins involve two ova fertilized by separate sperm. Monozygotic (identical) twins involve a common placenta, same genotype, and common chorion.

---

Option B: Monozygotic multiples form from a single egg and sperm combination that splits after conception. If the split is delayed for a few days, the embryos will develop with a single, shared placenta.

Option C: Identical twins share all of their genes and are always of the same sex.

Option D: In the majority of cases, these multiples will be enclosed within a shared chorion (the outer layer of the sac that contains a fetus).

---