7. Contraception 2 (lecture) Flashcards
how do you inhibit sperm transport?
by thickening cervical mucus
which pill inhibits sperm transport by thickening cervical mucus?
progesterone only pill (POP)
what is the POP?
lower dose progesterone
what is POP a secondary action of?
COCP
progesterone depot
progesterone implant
intrauterine system
at lower doses, what does progesterone act to do?
progesterone doesn’t inhibit LH surge - ovulation still likely
but lower dose of progesterone will THICKEN cervical mucus - inhibiting sperm transport
(oestrogen still positive effect on hypothalamus and ant pit)
what is the principal action of progesterone only pill?
thickens cervical mucus, making it impenetrable to sperm
ovulation usually NOT prevented
what are the advantages of POP?
can be used where the COCP is contraindicated (cannot be used)
what are disadvantages of POP?
menstrual problems are common
must be taken at the same time each day (error for forgotten pills is only 3 hours late)
how should POP be taken?
pill containing progesterone only (lower dose)
taken everyday
explain how lower progesterone dose works? (POP)
lower dose, progesterone does NOT inhibit LH surge, ovulation still likely
lower dose only THICKENS cervical mucus, preventing sperm from penetrating
what are the 2 different coils used in inhibition of implantation?
intrauterine system (IUS) intrauterine device (IUD)
what does intrauterine system (IUS) contain?
progesterone
what does intrauterine device (IUD) contain?
copper
how do coils sit?
placed into the uterus
what is the principal action of IUS (system)?
progesterone reduces endometrial proliferation and prevents implantation
(high conc of progesterone, inhibits positive feedback of oestrogen)
what are secondary actions of IUS?
thickens cervical mucus
ovulation usually NOT prevented
what are advantages of IUS?
convenient
long duration of action
can also relieve menstrual disorders
what are disadvantages of IUS?
insertion may be unpleasant
IUS displacement / expulsion may occur
menstrual irregularity common in first 6 months
risk of uterine perforation (2/1000)
what is an IUS?
small device made of plastic with added slow-release progestogen, that is placed into uterus
how long does an IUS last?
can last between 3-5 years
what is the principal action of intrauterine device (IUD)?
contains copper
copper is toxic to sperm and ovum - prevents fertilisation
what are the secondary actions of IUD?
copper cause endometrial inflammatory reaction - prevents implantation
reduces penetration by sperm due to effect of copper on cervical mucus
what are the advantages of IUD?
convenient
long duration of action
can also be used as emergency contraception (up to 5 days after unprotected intercourse)
what are disadvantages of IUD?
insertion may be unpleasant
IUD displacement / expulsion may occur
periods may be heavier, longer, more painful
risk of uterine perforation (2/1000)
what is uterine perforation?
injury to surrounding blood vessels or viscera such as the bladder or intestine
what is an IUD?
small device made of plastic with added copper that is placed into the uterus
how long can IUD be effective for?
5-10 years
what is male sterilisation?
vasectomy
what is the mechanism of action of male vasectomy?
vas deferens interrupted to prevent sperm entering ejaculate
sperm produce in seminiferous tubules –> rete testes –> vas deferens
how is vasectomy performed?
under local anaesthetic
how do you confirm whether a vasectomy was successful?
post-operative semen analysis to confirm no sperm in ejaculate (approx. 12-16 weeks after surgery)
what are the advantages of sterilisation?
permanent
no hormonal side effects
what is sterilisation in females?
tubal ligation / clipping
what is the mechanism of action of tubal ligation / clipping?
fallopian tubes cut / blocked to stop the ovum travelling from the ovary to the uterus
how is tubal ligation / clipping carried out?
under local / general anaesthetic
what are the disadvantages of sterilisation?
should not be chosen if any doubt about having children in future
what is the failure rate of vasectomy in males?
1/2000
what is the failure rate of tubal ligation / clipping in females?
2-5/1000
