Lecture 12 - Contraception Flashcards
(33 cards)
Contraception
Block transport of sperm to avoid fertilisation of oocyte
Disrupt HPG axis to disrupt ovulation
Inhibit implantation of the conceptus into the endometrium
Methods of contraception
- Natural
- Barrier control
- Hormonal control
- Prevention of implantation
- Sterilisation
- Emergency contraception
Natural contraception
Abstinence
Withdrawal method
Fertility awareness
Lactation amenorrhoea
Abstinence
Not participating in intercourse
Advantages - 100% effective
Disadvantages - no sex
Withdrawal
Withdraw before ejaculate
Advantages - no devices or hormones used
Disadvantages
- not reliable
- May not withdraw in time
- pre-ejaculate contains sperm
- no STI protection
Fertility awareness
Using fertility indicators such as cervical mucous viscosity, temperature and length of menstrual cycle
Advantages- no hormones or devices used
Disadvantages - unreliable and no protection against STIs
Lactation amenorrhoea
Breastfeeding delays the return of ovulation after childbirth
- suckling stimulates inhibition of dopamine
- less inhibition of prolactin release
- prolactin inhibits GnRH release so less gonadal hormones released preventing ovulation
Disadvantages
- relies on exclusive breast feeding
- only effective for 6 months after giving birth
- unreliable
- No STI protection
Advantages
- no hormones or devices
Barrier protection
Male and female condoms
- prevents entrance of sperm into cervix
- can contain spermicide to kill sperm
Advantages
- reliable
- Protections from STIs
- condoms are widely available
Disadvantages
- Danger of expiring
- May rip
- Reduce sexual pressure
- Allergy
Hormone protection
Combined oestrogen and progesterone:
- COCP
- vaginal patches
- patches
High dose progesterone
- progesterone implant
- progesterone injection
Low does progesterone
- progesterone only pill (POP)
Combined oral contraceptive pill
Oestrogen and progesterone
Action:
Prevents ovulation due to negative feedback
Reduced endometrial receptivity to inhibit implantation
Thickens cervical mucus to inhibit perpetration of sperm
Reliability - 98%
Advantages
- Reliable
- no periods
- receive menstrual disorders
- reduced risk of ovarian cysts
- reduced risk of ovarian and endometrial cancer
Disadvantages
- no protection against STI
- compliance
- contraindications - BMI, migraines and breast cancer (risk of DVTs)
- side effects - breast tenderness, mood disturbance and bleeding
- increased risk of - DVTs, MI, Stroke, cervical and breast cancer
COCP missed pill rule
Taken for 21 days followed by 7 day break or with 7 day placebo
If miss 1 day - take the pill even if 2 pills in a day
Can’t miss more than 2 pills
High dose progesterone injection
Intramuscular injection every 12 weeks
Action:
- prevents ovulation by negative feedback reducing LH
- thickens cervical mucus to inhibit penetration of sperm
- prevents endometrial proliferation
Reliability - 99%
Advantages
- reliable
- does not disrupt sexual intercourse
- if can’t have COCP
Disadvantages
- appointment every 12 weeks
- side effects
- delay in fertility returning - 18 months to 2 years
- no STI protection
High dose progesterone implant
Last 3 years
Action:
- inhibits ovulation
- thickens cervical mucus to inhibit penetration of sperm
- prevents endometrial proliferation
Advantages:
- lasts for 3 years
- reliable
- reversible
- alternative for people who can’t have COCP
- natural fertility returns quickly when removed
Disadvantages
- minor procedure
- side effects - 1/3rd no bleeding, normal bleeding, bleeding continuously
- no STI protection
- nearer to the end of the 3 years, may get bleeding
Low dose progesterone - progesterone only pill
Taken everyday without break
Action:
- thickens cervical mucous
- ovulation usually not present
Reliability - 99%
Advantages
- quickly reversible
- reliable
- doesn’t disrupt sexual intercourse
- can be used when can’t use COCP
Disadvantages
- user dependent
- common menstrual problems
- no protection against STIs
- interacts with other meds
- risk of ectopic pregnancy - reduced motility of myometrium
Implants
Intrauterine system
Intrauterine device
Intrauterine system
Plastic device that releases progesterone
Works for 3 - 5 years
Action:
Prevents implantation
Reduces endometrial proliferation - controls menorrhagia
Thickens cervical mucus
Advantages:
Longw duration of action
Can limit menorrhagia
Disadvantages:
- Unpleasant insertion
- risk of uterine perforation
- menstrual irregularity
- doesn’t protect against STIs
- displacement or expulsion may occur
Intrauterine device
Plastic device with added copper
Works for 5 - 10 years
Action:
copper is toxic to sperm and ova
Inflammation of endometrium - prevents implantation
Changes consistency of cervical mucus
Advantages:
Long duration of action
Reliable
Disadvantages:
- Unpleasant insertion
- risk of uterine perforation
- menstrual irregularity
- doesn’t protect against STIs
- displacement or expulsion may occur
- menorrhagia
Sterilisation
Vasectomy
Tubal ligation or clipping
- permanent
- no side effects
Vasectomy
Vas deferens cut or tied to prevent sperm from entering the ejaculate
Under local anaesthetic
12 - 16 weeks after, a semen analysis is done to check success as does not work straight away
Failure rate: 1 in 2000 males
Tubal ligation/clipping
Fallopian tubes cut or blocked to stop the ovum travelling from the ovary to the uterus
Under local or general anaesthetic
Failure rate: 1 in 200-500 women
Emergency contraception
IUD - up to 5 days after sex
Emergency pill with ulipristal acetate- up to 5 days after sex
Emergency pill with levonorgestrel- up to 3 days after sex
(High dose progesterone)
Subfertility
Failure of conception in a couple having regular unprotected coitus for 1 year
Regular = 2 to 3 times a week
Primary subfertility
Someone who has never conceived a child in the past is having trouble conceiving
Secondary subfertility
When someone who has been pregnant in the past is having trouble conceiving again
