Case Study 1

Question 1

case study situation

Answer 1

After struggling to conceive, Sara completed a round of in vitro fertilization (IVF) and found out she is pregnant with twins. During a routine ultrasound test is was discovered that the twins shared an amniotic sac. Sara didn’t understand the significance of this but after the twins were born she wanted to know if they were identical or fraternal.

Question 2

In terms of the steps of fertilization and implantation, what is the difference between the two types of twins?

Answer 2

identical twins = when the morula splits in two parts

fraternal twins = if two oocytes are fertilized

Question 3

Based on the ultrasound which type of twins does Sara have? How do you come to this conclusion?

ultrasound says that twins shared an amniotic sac

Answer 3

Identical twins because they share the same amniotic sac and that’s only possible with identical twins because fraternal twins are developed in two different oocytes so there cant share the same amniotic sac

Question 4

Based on all this information, around what day in development do you think the twins first formed?

Answer 4

7-12 days after fertilization
- b/c
The splitting (at hatching) can only happen after the amniotic sac has formed

Question 5

what type of twins are they

Answer 5

monochorionic monoamniotic