Contraception and Infertility Flashcards
List the different types of contraception.
'Natural' contraception Prevent sperm from entering ejaculate Prevent sperm from reaching cervix Prevent ovulation Inhibit transport along fallopian tube Inhibit sperm passing though cervix Inhibit implantation
Explain ‘natural’ contraception.
Contraception without the use of an artificial device or procedure
Abstinence
Coitus interruptus
- But there is sperm in pre-ejaculate
Rhythm method
- Need regular cycle, assuming max sperm survival of 7
days, ovum survival of 1 day, for a regular 28 day cycle,
with ovulation on day 14 or 15, the fertile period is day
7-6 of cycle. So have sex not on these days
Explain the prevent sperm from entering ejaculate method.
Vasectomy
Divide vas deferens bilaterally
Ensure ejaculate free of sperm before relying on for contraception
Explain the prevent sperm from reaching cervix method.
Barrier methods of contraception Condoms - Readily available, also protects against sexually transmitted diseases. - Effective is used correctly
Diaphragm
- Lies diagonally across cervix.
- Needs correct fitting. Does not completely occlude passage of sperm. Holds sperm in acidic environment of vagina and reduces survival time.
Cap
- Fits across cervix - physical barrier
(spermicide - most effective used in conjunction with barrier contraception)
Explain the prevent ovulation method of contraception.
Hormonal contraception
Combined OCP
- Oestrogen and progesterone
- Negative feedback to hypothalamus/pituitary - inhibits
follicular development
- Oestrogen - loss of positive feedback midcycle, so no
LH surge
Depot progesterone
- 3-monthly injections of progesterone, negative
feedback to inhibit ovulation
Progesterone-only pill
- Low-dose progesterone - may inhibit ovulation
Progesterone implants
- May inhibit ovulation
Explain the inhibit transport along fallopian tube method.
Sterilisation Occlude fallopian tubes - Clips - Rings - Ligation May rarely (1:300-500) recanalise
Explain the inhibit sperm passing through cervix method of contraception.
Affect cervical mucus - thick ‘hostile’ mucus. progesterone mediated
- Combined OCP
- Depot progesterone
- Progesterone implant
- Progesterone only pill
Main mode of action of POP and implant
Explain the inhibit implantation method of contraception.
Hormonal contraception Affect receptivity of endometrium, Direct effect. Plus absence of corpus luteum prevents preparation of endometrium for implantation - OCP - POP - Progesterone implant - Depot progesterone
Post-coital contraception
- Combined oestrogen/progesterone high dose, or
progesterone only
- Up to 72 hours after intercourse
- May disrupt ovulation. Blocks implantation. May also
impair luteal function
- Intra-uterine device
- (may also be as post-coital contraception up to 5
days after ovulation)
Intrauterine Contraceptive Device
- Inert or copper containing, or progesterone
impregnated
- Copper interferes with endometrial enzymes, and may
also interfere with sperm transport onto fallopian tubes
- Interferes with implantation
Give the definition of infertility.
A failure to conceive within 1 year
Give some statistics about infertility.
Affects approximately 15% of couples
Primary (no previous pregnancy) and secondary (previous pregnancy, successful or not)
The problems are:
20-25% Male
45-60% Female
20-30% unexplained
What are the categories of infertility mechanisms?
Coital problems
Anovulation (15-20%)
Tubal occlusion (15-40%)
Abnormal/absent sperm production (20-25%)
Explain the anovulation mechanism of infertility.
Anovulation cycle where no oocyte is released during a menstrual cycle
Occasional anovulatory cycles normal, especially at extremes of reproductive life.
Can be caused by:
- Hyperprolactinaemia, weight loss, exercise, stress
- (Hypothalamus, GnRH)
- Pituitary tumours, necrosis
- (Pituitary, LH, FSH)
- Ovarian failure, menopause, radiotherapy,
chemotherapy
- Ovary, oestrogen, progesterone
- Polycystic Ovarian Syndrome
Say a little about PCOS and it’s relation to infertility
Uncertain pathogenesis - originates at pituitary or ovarian level?
Increased androgen secretion
Raised LH/FSH ratio
Insulin resistance
Multiple small ovarian cysts
Anovulation - often amenorrhoea or oligomenorrhoea.
How do you diagnose anovulation?
Serum progesterone level in mid-luteal phase (approx. day 21
How do you differentiate the cause of anovulation?
By looking at hormone levels
Condition - LH - FSH - Oestrogen Menopause - High - High - Low Ovarian failure - High - High - Low Hypothalamus/Pituitary failure - Low - Low - Low PCOS - Increased ratio - Normal
