"Medical Physiology Clinical Correlation: In Vitro Fertilization" 4/6

Question 1

What are the common causes of male infertility?

Answer 1

1. Low sperm count
2. Abnormal sperm - teratospermia
3. Slow sperm - asthenozoospermia
4. Genetic issues

Question 2

Besides unexplained etiology, what is the most common cause of male infertility?

Answer 2

Varicocele, like a varicose vein of the testes

Question 3

Who should consider IVF?

Answer 3

Tubal factor infertility (blocked/absent fallopian tubes)

Male factor infertility (low sperm count/motility, abnormal morphology)

Other causes of infertility, after failing treatment with other therapies (ovulation disorders, endometriosis, cervical factor infertility, immunological infertility, unexplained infertility, )

Advanced reproductive age

Ovarian failure (donor eggs required)

Question 4

Why do you overstimulate the ovaries?

Answer 4

To gather as many eggs as possible, b/c
IVF has low success rate
Usually only 1 mature egg is produced per cycle
A large number of oocytes improves pregnancy rates

Question 5

Inhibin is produced by what cell and acts on what organ?

Answer 5

Inhibin is produced by granulosa cells

Question 6

What is the function of clomophine?

Answer 6

Clomiphene inhibits negative feedback of
estrogen on hypothalamus, resulting in
increased secretion of GnRH and FSH/LH

Question 7

How does a GnRH agonist function?

Answer 7

GnRH agonists: 
-- D-amino acid substitution of Gly 
    in position 6 enhances increase 
    binding affinity and decrease 
    degradation.

Question 8

What is the most commonly prescribed IVF protocol?

Answer 8

GnRHa long protocol
reduced amounts of LH
higher clinical pregnancy rate

Question 9

What is ovarian hyperstimulation syndrome, OHSS?

Answer 9

Anexcessiveresponse to the medicines (especiallygonadotropins) used to stimulate follicle growth due to a large number of growing follicles (>25) along with high estradiol levels (>4000 pg/ml).

Symptoms: abdominal bloating, nausea, and weight gain due to transudation of protein rich fluid

Treatments: – decreased activity

                - - drinking electrolyte-rich fluids
                - - draining fluid that accumulates in the abdomen
                - - medication for nausea

Question 10

What is capacitation?

Answer 10

– Capacitation: incubation of sperms in protein-supplemented media for up to four hours

Question 11

Who is eligible for standard oocyte insemination?

Answer 11

Patients with good quality of sperm and egg

Question 12

What is ISCI, intracytoplasmic sperm injection?

Answer 12

Under the microscope, put one sperm in one egg

Question 13

What is the preferred day of transfer for IVF embyros?

Answer 13

Blastocyst stage day 5
suited to younger patients or patients with more embryos

Day 3 cleavage for older patients, or previous IVF failure, or patients with less than 6 embryos.

Question 14

What is luteal phase support and why is it important?

Answer 14

Why?

• • abnormal endometrial maturation due to extremely high levels of estradiol and androgen resulting from ovarian stimulation
• • removal of a large number of granulosa cells during oocyte retrieval could lead to inadequate production of progesterone

How?

• • progesterone supplementation daily during the luteal phase (intramuscularly or vaginally)
• • hCG once or more during the luteal phase (intramuscularly)