Contraceptions
- Created by: kpritchard16
- Created on: 21-12-18 18:18
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- Contraception
- How can we disrupt normal HPG axis?
- prevent follicle development
- block corpus luteum
- unreceptive endometrium
- prevent ovulation
- Aim
- prevent pregnancy by either blocking access of sperm to egg or disrupt female reproductive cycle
- hormonal contraceptives
- progesterone-only contraceptives
- Efficacy
- very low failure rate (< 1%) if taken correctly
- Depo contraceptive injections (medroxyprogesterone acetate)
- effect ovaries (follicles)
- inhibit follicle maturation, inhibit ovulation, inhibit corpus luteum
- higher dose of progesterone, inhibit GnRG release in hypothalamus inhibit FSH and LH secretion in anterior pituitary
- effect uterus (endometrium)
- thicken cervical mucous, modify tubule motility, endometrial changes
- effect ovaries (follicles)
- Mini-pill
- side effects
- rare (acne, breast tenderness and breast enlargement, mood changes, headaches, nausea)depo injections - can take up to 2 years to recover normal fertility
- Efficacy
- combined oral contraceptives
- Hormonal contraception containing estrogen and progestin, which acts by suppressing ovulation, thickening the cervical mucus to block semen, and altering the uterine decidua to prevent implantation
- oestrogen and progesterone effect on female reproductive axis
- inhibits GnRH release from hypothalamus and decrease response in anterior pituitary, inhibits FSH and LH secretion from anterior pituitary
- oestrogen and progesterone effect on ovaries (follicles)
- Inhibit follicle maturation, inhibit ovulation, inhibit corpus luteum
- oestrogen and progesterone effect on uterus (endometrium)
- Thicken cervical mucous, modify tubule motility, endometrial changes (thins)
- Efficacy
- Very low failure rate (0.05%) - interferes with multiple steps of ovulation. Usually caused by missed doses, drug interactions (some antibiotics), diarrhoea and vomiting
- Side effects
- increased risk of CVD, breast cancer, minor effects include nausea, weight gain, depression
- Health benefits
- decreased risk of ovarian and endometrial cancer, decreased incidence of PID and ovarian cysts
- morning after pill
- Emergency contraception used within 72 hrs after unprotected sex.High dose Progesterone only.
- Primary mechanism
- Inhibit ovulation (will not work if this has already occurred). Suppression of HPG - inhibit FSH and LH.Efficacy rates ~ 75-85%.
- RU486 (mifepristone): abortive agent(not in UK)
- Progesterone antagonist
- MOA
- depends on stage of cycle:Mid-cycle disrupts ovulation, Luteal phase prevents implantation, after implantation causes loss of foetus
- Mimics endogenous hormone
- progesterone-only contraceptives
- Male contraceptive pill
- side effects
- sexual dysfunction & weight gain
- MOA
- stop sperm production
- inhibit sperm motility
- inhibit testosterone production
- example - dimethandrolone undecanoate (DMAU) - androgen receptor agonist.
- side effects
- How can we disrupt normal HPG axis?
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