Contraception Flashcards
What are the advantages of contraception?
Choice/control for personal/medical reasons
Pregnancy spacing (health)
Cost sometimes
Saves lives globally
What are the disadvantages of contraception?
Changes in sexual habits
Increased promiscuity
Medical complications
Cost sometimes
What must be considered in a contraceptive consultation?
Health Age Desire for fertility Social/religious/ethical Education Compliance Cost
What are the 4 different types of contraceptive methods from least to most reliable?
- Natural/physiological
- Barrier
- Hormonal
- Surgical
What natural/physiological contraceptive methods exist?
- Calendar rhythm method: prevent sperm/egg interaction
- Coitus interruptus: prevent sperm/egg interaction
- Lactation: prevents ovulation but only with exclusive regular feeding
What is the mechanism of action of the calendar rhythm method?
In rhythm with woman’s natural fertility as the ovum has a limited period of fertilised so intercourse should be avoided in fertility window, 4-5 days prior and 1-2 days after predicted ovulation
When does ovulation normally take place? What is a tell-tale sign?
~ day 14
Spinbarkeit (spinnability) of vaginal mucus or higher body temperature
What are the advantages and disadvantages for the calendar rhythm method and coitus interruptus?
Adv: cheap/no side effects, no medical contraindication and no religious/ethical problems
Disadv: limits sexual activity, education (3-6mths), failure rate higher and no STI protection
What is the mechanism of action of lactation?
Regular and exclusive (i.e. no bottle feeds) breastfeeding for ~6 months will induce production of prolactin which inhibits secretion of FSH, suppressing HPO axis so no ovulation takes place but failure rate is an issue
What is coitus interruptus?
Penile withdrawal before ejaculation
What 4 barrier contraceptive methods exist?
- Condom
- Diaphragm
- Cervical cap
- Plus - spermicide
What is the main mechanism of action of barrier contraceptive methods?
Prevent sperm/egg interaction
How does the diaphragm and cap work?
Inserted in the vagina with spermicide in it just before sex, left in for 6 hours after sex and then can be taken out so patients need to be educated on its use
What are the advantages and disadvantages of condoms?
Adv: cheap/readily available and STI protection
Disadv: latex allergy, some sensation loss/interruption/accidents, education (beware of body oil and Vaseline w/ latex) and female condom even less popular
What is the mechanism of action of long acting reversible contraception (LARC)?
Copper IUD releases copper which is a spermicide and mechanically prevents implantation
What are the advantages of long acting reversible contraception (LARC)?
Long-term Doesn't limit/interrupt sexual activity IUCD copper has no artificial hormones Amenorrhea Decreased dysmenorrhea Partner unaware (sometimes string can be felt in IUCD)
What are the disadvantages of long acting reversible contraception (LARC)?
Decreased libido Irregular bleeding Amenorrhea may be beneficial Cost Invasive No STI protection
When should the intra-uterine contraceptive device (IUCD) be used?
Long-lasting for 1-12 years so good for women who are older/parous, if compliance is a problem and can be used as emergency contraception is implanted within 5 days of unprotected sex
What are the complications of the intra-uterine contraceptive device (IUCD)?
Expulsion
Perforation
Infection (PID) as string provides a route up to uterus
Ectopic
What are the side effects of the cooper/inert intra-uterine contraceptive device (IUCD)?
Bleeding
Cramping
Usually good or bad
What is a termination (TOP)?
Often called an abortion - legal to 24/40 weeks gestation in UK which can be:
- Medical (up to 9/40): Mifepristone/Misoprostol
- Surgical: vacuum aspiration (15/40) or dilation and curettage (>15/40)
What is surgical sterilisation?
Irreversible method of preventing sperm/egg interaction via surgical interruption:
- Male = vasectomy
- Female = tubal ligation
What are the problems with surgical sterilisation?
Requires counselling
Costly
Invasive
Failures still exist
What are oral hormonal contraceptives?
Synthetic steroid hormones that mimic the function of oestrogens and progesterone:
- Combined inc. oestrogen and progesterone
- Progesterone-only version
What is the mechanism of action of oral hormonal contraceptives?
Act upon oestrogen and progesterone IC TFs by diffusing across cell membranes:
- ER1⍺ and ERβ for oestrogen
- PR-A and PR-B for progesterone
Binding of hormone drives receptor activation via dissociation from HSP90 so active receptor dimers then form, move into nucleus and influence gene expression influencing tissue growth, regeneration and secretion of hormones
What are the primary outcomes of oral contraceptives?
SUPPRESSION OF OVULATION:
- Combined: must be taken at right time to disrupt critical endocrine events required for ovulation
- Progesterone only: taken asynchronously and exerts additional effects that disrupt fertilization and implantation (makes body think you are already pregnant)
What drives ovulation?
Endocrine dynamics and relative TIMING of hormone secretion and activity - LH surge essential for this
What happens to the corpus luteum if implantation occurs or does not occur?
Progesterone is produced by the corpus luteum during the menstrual cycle and with +ve embryo implantation, it is sustained and progesterone levels remain high promoting pregnancy but if there is no embryo implantation, it disintegrates so progesterone levels fall contributing to menses and the cycle resumes
What usually happens to progesterone levels throughout the menstrual cycle?
LOW in follicular phase
HIGH in luteal phase
What is the problem with progesterone-only contraceptive pills?
High doses are required to suppress ovulation which can cause sig. nausea and this is still not 100% effective whereas combined pill is >99.8% effective so the progesterone-only pill is only used for emergency contraception or in situations when oestrogen-derived complications/risks occur
What are the effects of progesterone?`
- Negative feedback to hypothalamus + anterior pit. to reduce FSH/LH synthesis inhibiting ovulation
- Inhibits endometrial gland development making implantation less favourable as sufficient nutrients would not be available
- Thickens cervical mucus so inhibits sperm motility
What can progesterone intra-uterine systems (IUS) be used for?
E.G. Mirena can incorporate a progesterone-releasing polymer component that lasts up to 5 years which is a very effective contraceptive system BUT can also treatment conditions such as menorrhagia
What are the common adverse effects of oral contraceptives?
Breakthrough bleeding
Nausea
Depression
Increased risk of CVD complications with oestrogen-containing pills (e.g. thromboembolism, stroke, IHD, raised BP)
Slight increase in breast cancer risk in long-term use
What other benefits to contraceptives offer?
Relief of symptoms of endometriosis, dysmenorrhoea, menorrhagia and acne in women
Progesterone reduces risk of endometrial cancer too
