ART Flashcards

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1
Q

What is infertility?

A

Infertility defined as the failure to conceive after 1 year of regular unprotected intercourse.

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2
Q

What are the causes of infertility - 1 in7 couples in the UK (4)

A

1)Mechanical blockage to egg and sperm meeting:
Infection/occlusion of vas deferens or uterine tubes.
Previous ligation for sterilisation.
Endometriosis.
Congenital defects.

2)Failure of gamete production or release:
Anovulation, maternal age, PCOS.
Azoospermia, asthenozoospermia, teratozoospermia.

3)Failure of fertilisation/implantation & miscarriage.
Genetic factors.
Endometrial receptivity, maternal age.

4)Unknown/unexplained.

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3
Q

Methods of Assisted Reproductive Technology (6)

A

Inducing ovulation with exogenous hormones.
By-passing the uterine tube (IVF).
Direct collection of sperm from the testis/epididymis.
Direct insertion of the sperm into the egg (ICSI).
Donor gametes.
Combination of the above.

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4
Q

Inducing ovulation - exogeneous gonadotrophins (3)

A

Used to treat women who are anovulatory or who have oligo/amenorrhoea.

The aim is to induce single dominant follicle.

Daily injections…monitor by ultrasound during the cycle. (LH +FSH)

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5
Q

Inducing ovulation by removing negative feedback (5)

A

Gonadotrophin levels may be normal, but are not cyclical.

Inter-cycle rise in FSH relies on death of the corpus luteum. ie. fall in levels of progesterone and estradiol.

There is no corpus luteum in the absence of ovulation

Cannot reduce progesterone as there has not been a corpus luteum to make any.

There are follicles in the ovary making estrogen so we can remove the negative feedback of this.

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6
Q

2 ways to remove estrogen feedback: (2)

A
  1. Block the E2 receptor on the pituitary gonadotroph cells with SERM: Clomid/Clomiphene.
  2. Stop E2 being made by using an aromatase inhibitor (no conversion from T to E2). Drugs ending in ‘zole’ eg. Letrozole.
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7
Q

IVF cycle outline (9)

A

1)Hypothalamic-pituitary downreg. (GnRH)

2)Ovarian stimulation with FSH (ultrasound monitoring)

3)hCG trigger

4)Oocyte retrieval

5)Fertilisation in vitro

6)Embryo culture 3 – 5 days

7)Embryo or Blastocyst Transfer

8)Pregnancy confirmation

9)Luteal phase support - Cyclogest (progesterone)

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8
Q

Why are the ovaries hyperstimulated during IVF?

A

As failure will occur at each stage (9), we require as many eggs as possible and so hyper-stimulate the ovaries to increase follicle numbers.

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9
Q

Multiple follicle selection with exogenous gonadotrophin explained (3)

A

1)there is no df selection = most/all follicles will survive
2) = >oestrogen production = ovulation (surpasses threshold)
3) prevention of LH surge to prevent ovulation

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10
Q

Explain how to conduct controlled ovarian stimulation (5)

A

1) Downreg. HPG axis using GnRH antagonist or agonist.

2) Give FSH by subcutaneous injection= Growth of multiple follicles.

3)Monitor follicle growth with ultrasound until most follicles 12–19mm.

4)At this point hCG trigger given (GnRH agonist or Kisspeptin may be used).

5) 36 hours allowed for completion of meiosis I and initiation of meiosis II before egg collection.

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11
Q

How does Oocyte Retrieval (34-38 hours post hCG trigger) occur?

A

Collect mature eggs from ovary using transvaginal needle aspiration under
ultrasound guidance .

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12
Q

How do you prepare sperm for IUI or IVF? (4)

A

1) collect semen and put into a solution w/ isotonic solution + centrifuge (x400 -5mins)

2) = will separate to give live sperm (motile fraction)

3) I egg + sperm in each bubble of media in petri dish (IVF)
or
directly inject sperm into uterus (IUI)

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13
Q

What are the control factors for IVF? (6)

A

nutrients, acidity, humidity, temperature, gas composition of air, and exposure to light.

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14
Q

Describe the incubation of the sperm + egg in IVF (3)

A

The sperm and the egg are incubated together at a ratio of about 75,000:1.

Duration of this co-incubation traditionally 16 – 18 hours .

Approximately 65% of the eggs will fertilize.

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15
Q

Embryo culture explained (3)

A

1) The fertilised egg has 2 pronuclei = 1st sign of fertilisation
2)The developing embryo contains 6-8 cells 3 days after fertilisation
3) Blastocyst 5 days old approximately 100 cells

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16
Q

Explain embryo transfer (3)

A

Embryo transferred to the patient’s uterus through catheter

goes through the vagina and cervix, usually under ultrasound guidance.

Single embryo transfer is the norm in order to avoid multiple pregnancies, though 2 – 3 may be transferred in women over 40 or who have had repeated implantation failure.

17
Q

Success rates (3)

A

Around 6.5 million children born worldwide to date.

Approximately 70,00 embryo transfers per year in the UK.

highest live birth/ embryo transfer rates for younger ages

18
Q

Intracytoplasmic sperm injection - ICSI (3)

A

1)Used in low sperm count, low motility or repeated fertilisation failure.

2)Single sperm used so can collect sperm by needle aspiration from epididymis or testis.

3)Inject sperm into the egg.

19
Q

Is ICSI safe? (5)

A

Natural means of sperm selection is bypassed.

Some evidence of increased genetic damage, but equivocal.

Other defects 9.9% compared with 5% of non-ICSI.

Patients may be being pushed to ICSI as higher fertilisation rates. In 2013 there were more ICSI cycles than IVF for the first time.

Biggest risk with infertility treatment is still multiple pregnancy.

20
Q

Gamete donation - Sperm (3)

A

Freezing (cryopreservation) is essential for donor sperm to test for STDs/STI’s (6 month wait)

Reasonable function after thawing

Change in the law may reduce the number of UK donors

21
Q

Gamete donation - eggs (4)

A

Shortage of donor eggs

IVF cycle required to procure eggs

Eggs can now be cryopreserved by vitrification - prevent crystallisation in the egg

Can be a waiting list/expensive.

22
Q

Donor identity and anonymity (4)

A

Since 2005 donors also have right to access information about themselves
held by the HFEA.

  1. Whether their donation has been successful.
  2. The number of children born as a result of their donation
  3. The sex and year of birth of any children born.

4.Children born from donations in the UK have the right to ask the donors identity once they are over 18.

23
Q

Access to infertility treatment- q’s to think about (7)

A

Does everyone have the right to have a child?

Do they have the right to investigation?

Should there be an age limit?

What about population growth/children in care?

Can the NHS afford to supply this treatment? IVF/ICSI? Donor gametes?

Only available to the wealthy?

Current system is divisive geographically and financially. NICE recommend
3 free IVF cycles per couple (under 35), but funding varies between Clinical
Commissioning Groups (CCG’s).