Subfertility Flashcards
recall the mode of action, efficacy, indications, contraindications and complications (and their management) of subfertility therapies (incl. intrauterine insemination (IUI), in-vitro fertilisation (IVF), intra-cytoplasmic sperm injection (ICSI) and ovulation induction)
Define subfertility.
No universal definition but usually failure to conceive after 12 months of regular unprotected intercourse
How common is infertility?
Infertility affects around 1 in 7 couples.
What is the difference between primary and secondary infertility?
Primary - have never conceived together
Secondary - previously conceived (either may have conceived in previous relationship)
What are the conception rates for couples who have regular sex for 1year and 2 years?
Of couples who have regular sexual intercourse:
70% will conceive within 6 months
80% within 12 months
90% within 24 months
With regular intercourse, what is the chance of a couple conceiving in a single menstrual cycle?
18-20% i.e we are relatively infertile
What is the most important factor affecting fertility?
Female age - fertility falls sharply after age 36 years and further dips after age 40 years. This is due to decline in quality and quantity of eggs
Both frequency and timing of sexual intercourse also impact strongly on the chance of conceiving naturally.
What is the effect of age on male fertility?
Male age is also an important factor; semen quality
tends to fall in men over the age of 50, while frequency of intercourse tends to fall in men over the age of
40.
What are the most common causes of infertility in a couple?
- male factor 30%
- unexplained 20%
- ovulation failure 20%
- tubal damage 15%
- other causes 15%
What are the female causes of subfertility? Give an example of the aetiology of each.
- Ovulatory disorders e.g. PCOS
- Tubal damage e.g. in PID or endometriosis
- Uterine disorders - e.g. fibroids especially if large (>5cm) + submucosal; endometrial polyps and Asherman’s syndrome
Other:
- Decreased ovarian reserve and age
- Lifestyle and PMH - smoking, DM, epilepsy, thyroid, bowel disease
What are the male causes of subfertility? Give an example of the aetiology of each.
- Compromised sperm number e.g. orchitis or epididymitis where there is damage to spermatogonial cells or stores; pelvic radiotherapy; torsion
- Medical conditions and lifestyle e.g. DM, occupational exposure
- Erectile difficulties or ejaculation problems
- Genetic
What are the genetic aetiologies of male subfertility? What investigation can be done for this?
- Kleinfelter XXY or other aneuploidies of sex chromosomes;
- Structural abnormalities of autosomes like inversions, deletions or balanced translocations;
- Microdeletions of the azoospermic factor (AZF) regions of Y chromosome –> low sperm count and motility
Investigation: Karyotype
How long do sperm vs eggs survive in the female reproductive tract?
Eggs are thought to be fertilizable for about 12–24 hours
postovulation, while sperm can survive in the female reproductive tract for up to 72 hours.
What two basic investigations should be done for couples who are infertile?
- semen analysis
- serum progesterone 7 days prior to expected next period. For a typical 28 day cycle, this is done on day 21.
Only done iafter 12 months of infertility.
What progesterone level indicates that ovulation is occurring in the female?
< 16 nmol/l = Repeat, if consistently low refer to specialist
16 - 30 nmol/l = Repeat
> 30 nmol/l = Indicates ovulation
What day 21 progesterone level would prompt referal to fertility specialist?
< 16 nmol/l
This should be consistent on a repeat
When should sperm analysis be performed? How quickly must the sperm reach the lab? When can it be repeated?
Between 3-5 days of abstinence from sex
Within 1 hour
Can only be repeated after 3 months to allow spermatogenesis to occur (sometimes abnormal initially due to insults such as viral infection)
What are the parameters assessed in sperm analysis? What is the normal sperm number per ml?
- volume > 1.5 ml
- pH > 7.2
- sperm concentration > 15 million / ml
- morphology > 4% normal forms
- motility > 32% progressive motility
- vitality > 58% live spermatozoa
NB: different ranges exist in different guidelines. These represent results at the 5th centile, as done by WHO.
What are some key counselling points to give subfertile couples?
- Folic acid
- Aim for BMI 20-25
- Advise regular sexual intercourse every 2-3 days (without use of lubricants which are spermicidal)
- Reduce smoking and alcohol
How can stress affect fertility?
Direct influence on the hypothalamic-pituitary-ovarian axis interfering with regular ovulation and may reduce conception by reducing libido and frequency of intercourse.
Summarise the medical and surgical managements for subfertility.
What are the steps carried out in IVF?
- Pituitary down-regulation using GnRH - blocks LH surges and premature ovulation.
- Controlled ovarian stimulation - daily SC gonadotrophin injections to cause follicle recruitment. Monitor with TVUSS for timing of egg collection. Ideally 15 follicles should be recruited. Measure endometrial thickness.
- Inihibition of premature ovulation - GnRH agonist to blcok oocyte maturation and ovulation so that scheduled egg collection can take place
- hCG trigger - replicates LH surge to allow for eggs to be collected
- Egg collection - at 37 hours post hCG trigger; done under anaesthesia where needle is inserted into ovaries under TVUSS control and follicular flui aspirated from each follicle that contains an oocyte
- Fertlisation - insemination of 100,000 sperm in petri dish with an egg or isolation of specific sperm prior and their injection into the cytoplasm (intracytoplasmic sperm injection ICSI)
- Embryo culture - incubation iundr strict condition of temp, pH, humidity and oxygen.
- Embryo transfer - occurs at days 2, 3, or 5 of development. Most successsful when at the blastocyst stage at time of implantation. Transferred using a soft plastic catheter into the uterus under USS. Choice of how many are transferred depends on couple and clinician.
- Embryo cryopreservation - for future use
- Luteal phase support by progesterone supplementation- prevents premature LH surge which would reduce ability of corpus luteum to produce progesterone.
- Pregnancy test done at 14 days post embryo transfer
