L07 - Infertility

Question 1

Define fertility.

Answer 1

• A measure of the actual outcome of the reproductive process
• Measurable as the number of children born to an individual couple

Question 2

Define fecundability.

Define fecundity.

Answer 2

• Fecundability is the monthly chance of pregnancy (within a single menstrual cycle)
• Fecundity is a measure of the ability to conceive and achieve a live birth

Question 3

Define infertility.

Define subfertility.

Answer 3

Infertility:

• The inability to conceive after a period of unprotected intercourse

or

• The inability to carry a pregnancy to term
• NICE defines infertility as failing to get pregnant after two years of regular unprotected sex

Subfertility:

• A state of reduced fertility

Question 4

What proportion of female infertility is accounted for by disorders of ovulation?

Answer 4

Disorders of ovulation account for 40% of female infertility

Question 5

List 5 disorders of ovulation that contribute to female infertility.

How do these disorders cause infertility?

Answer 5

1 - Absent cycles (primary / secondary amenorrhoea or oligomenorrhoea)

2 - Idiopathic ovarian failure (gonadotropin secretion is normal but is insufficient to support a normal cycle due to reproductive organ insensitivity)

3 - PCOS (associated with high LH and androgen levels)

4 - Luteinised unruptured follicle syndrome (eggs are deficient so the follicle doesn’t rupture)

5 - Abbreviated luteal phase (due to decreases in progesterone causing poor luteinisation)

Question 6

List 2 causes of tubal obstruction that contribute to infertility.

Answer 6

1 - Secondary to pelvic infection, e.g. STDs

2 - Sepsis post-abortion or post-pregnancy

Question 7

How might infection impair oocyte and sperm transport in the female reproductive system?

Answer 7

Infection can cause loss of cilia on the intraluminal cells and scarring, causing oocytes and sperm to adhere to the walls of the tract

Question 8

What is endometriosis?

Answer 8

• Escalated endometrial tissue growth in ectopic sites
• As the tissue is still under the influence of oestrogen and progesterone, it can bleed and cause inflammation
• This can disrupt implantation and affect ovarian reserve

Question 9

List 4 maternal problems (problems occurring after conception during pregnancy) that contribute to infertility.

Answer 9

1 - Cervical incompetence (cervical tissue widens and thins prematurely before term, causing premature birth)

2 - Implantation defects (ectopic pregnancies)

3 - Autoimmune diseases, e.g. lupus

4 - Immunological incompatibility between ABO or Rhesus blood groups

Question 10

What is the difference between a biochemical and a clinical pregnancy?

Answer 10

• Pregnancy is tested for biochemically by testing for hCG in the blood and urine 18-30 days after the initiation of the last period
• Pregnancy is tested for clinically by:

1 - Ultrasound at 5 weeks to establish the presence of a foetal sac

2 - Ultrasound at 7 weeks to establish the presence of a foetal heart

Question 11

What are the most common causes of chromosomal abnormalities resulting in miscarriage?

Answer 11

• Translocations
• Errors of ploidy (deletions, duplications)
• Errors of number (somy; loss/gain of chromosome)

Question 12

Define normozoospermic.

Define oligozoospermic.

Define asthenozoospermic.

Define teratozoospermic.

Define azoospermic.

Answer 12

• Normozoospermic: >15mn/ml; 32% rapid forward progressive motility; & >4% normal morphology => normal
• Oligozoospermic: <15mn/ml => count reduced
• Asthenozoospermic: <32% rapid forward progressive motility => motility reduced
• Teratozoospermic: <4% normal morphology => morphology reduced
• Azoospermic: no sperm

Question 13

List 4 causes of failure of production of sperm.

Answer 13

• Congenital testicular deficiency – Klinefelter’s (47, XXY), Y chromosome deletions
• Maldescended testes (cryptorchidism) – reduced spermatogenesis & increased risk testicular cancer
• Acquired – trauma (e.g. testicular torsion) or orchitis (mumps)
• Endocrine disorders

Question 14

List 2 causes of failure of transmission of sperm.

Answer 14

1 - Erectile dysfunction

2 - Ejaculatory dysfunction e.g. retrograde ejaculation

Question 15

How does retrograde ejaculation differ from normal ejaculation?

Answer 15

• In normal ejaculation the contraction of musculature in the prostate, seminal vesicles and vas deferens (in response to SNS stimulation) will push seminal fluid and sperm into the urethra
• Ejaculation follows contraction of urethral and pelvic floor muscles, simultaneously there should be a contraction of the vesicular urethral sphincter to close the bladder neck and prevent retrograde ejaculation
• Retrograde ejaculation results from an incompetence of the urethral sphincter; this is typically associated with diabetes, paraplegia, or bladder-neck surgery
• As the bladder is the path of least resistance, the ejaculate passes into the bladder, and only a small amount (or none) will be expelled

Question 16

List 2 causes of total failure of transport of semen, causing an absent ejaculate.

Answer 16

• Post-infection -> bilat epididymal / vas occlusion
• Congenital bilat absence of vas deferens (CBAVD) – linked to CFTR gene mutation (chromosome 7) -> improper vas deferens development; assoc w/ CF

Question 17

What is unexplained infertility?

Answer 17

• Normal frequency & distribution of unprotected intercourse
• No obstructions/malformations in female/male genital tracts
• Normal follicle growth, maturation & ovulation w/ no inflammation signs
• Normal conc motile sperm, no anti-sperm abs, or other signs ongoing inflammation