L10 - Assisted Reproduction

Question 1

What is IUI?

When is it useful?

Answer 1

• Intrauterine insemination
• It involves injecting sperm directly into the uterus
• It is useful for couples who are fertile but have difficulty with intercourse

Question 2

Describe IVF.

Answer 2

1 - GnRH antagonists are given to prevent premature LH surge

2 - The ovaries are stimulated with recombinant FSH or human menopausal gonadotropin (HMG) to develop many follicles simultaneously (remember this will also antagonise the oestrogen and progesterone so the cycle is reset)

3 - HCG is administered to mimic the LH surge and cause final egg maturation (HCG is cheaper than LH)

4 - The oocytes are collected and inseminated in vitro by combining it with a sample of sperm in a petri dish

5 - An embryo is implanted into the uterus at the 4 cell stage

6 - Exogenous progesterone is administered to mimic the function of the corpus luteum in natural pregnancy

Question 3

Describe intracytoplasmic sperm injection (ICSI).

Answer 3

1 - GnRH antagonists are given to prevent premature LH surge

2 - The ovaries are stimulated with recombinant FSH or human menopausal gonadotropin (HMG) to develop many follicles simultaneously

3 - hCG is administered to mimic the LH surge and cause final egg maturation (hCG is cheaper than LH)

4 - A sample of sperm is collected and the most fertile sperm are selected

5 - The sperm are individually injected into the oocytes to achieve fertilisation

6 - An embryo is implanted into the uterus at the 4 cell stage

7 - Exogenous progesterone is administered to mimic the function of the corpus luteum in natural pregnancy

Question 4

When is hCG administered in IVF / ICSI?

Answer 4

hCG is administered 34-36 hours prior to egg collection in IVF / ICSI

Question 5

When is an embryo implanted in the uterus in IVF / ICSI?

Why?

Answer 5

• An embryo is selected and implanted from a culture of embryos 5-6 days post-oocyte collection
• This is because after 5-6 days, the blastocysts have developed past significant hurdles, such as:

1 - Switching on the embryonic genome

2 - Passing the stages of totipotency to pluripotency

Question 6

What are the indications for IVF?

Answer 6

1 - Male factor infertility

2 - Ovulation disorders, e.g. PCOS

3 - Premature ovarian failure

4 - Uterine fibroids

5 - Uterine polyps

6 - Endometriosis

7 - No eggs (egg donor IVF)

8 - No uterus (host surrogacy)

Question 7

What are the problems with IVF?

Answer 7

1 - Increased risk of multiple pregnancies

2 - Risk of ovarian hyperstimulation syndrome (OHSS)

3 - Risks of oocyte retrieval (infection or injury to the bladder, bowel or blood vessels)

4 - Increased risk of congenital abnormalities

5 - Expensive

6 - Very invasive

Question 8

What is preimplantation genetic diagnosis (PGD)?

Answer 8

Preimplantation genetic diagnosis (PGD) is the removal of one or two cells from the early embryo before implantation in order to select embryos without genetic disease