Lesson completed.

Up to which stage can totipotent embryonic stem cells be collected from the embryo?

In the figure you see an oocyte containing three polar bodies. What went wrong and what will be the most probable consequence? Choose the two correct options:

At which stage the embryo most likely reaches the uterus?

The first 4 stages in the figure above hardly show differences in size size. Between stages D and E, there is a very small size increase. Explain the reason of this very small increase in size between stages D and E and why that is required.

Question : What would be the most likely reasons that a blastocyst is present in the fallopian tube and resulted in an extra-uterine tubal pregnancy? Choose 3 correct options.

It has been demonstrated that some factors increase the risk of an ectopic pregnancy (EP) in women: • Pelvic inflammatory disease: Previous infection of the pelvic region e.g. caused by chlamydia, can sometimes damage the Fallopian tubes. Chlamydia is responsible for 30-50% of all ectopic pregnancies. • Prior pelvic or abdominal surgery: An embryo can implant in the scar tissue of the uterus lining, that was caused by a previous surgery • History of pelvic infections: Infection and inflammation can damage the lining of the tube and cause scarring that can prevent the embryo from passing to the uterus • Infertility: Women with infertility have a higher risk of ectopic pregnancy, possibly because tubal abnormalities are also a common cause of infertility. However, an ectopic tubal pregnancy only occurs when the pregnancy results from a natural menstrual cycle and not from an in-vitro fertilization (IVF) cycle. Why do you think an ectopic tubal pregnancy only occurs in a natural cycle? 

In the training manual you find an overview on the characteristics of the different Carnegie stages. Which characteristics are used to judge the correct development of the embryo, when referring to the Carnegie stages. Three options must be selected.