Contraception Flashcards
What are the common enzyme-inducing drugs?
Antibiotics – rifampicin and rifabutin
Antiseizure medications- carbamazepine, eslicarbazepine acetate, oxcarbazepine, perampanel, phenobarbital, phenytoin, primidone, rufinamide and topiramate (doses of 200mg daily or higher)
Antifungals - griseofulvin
Antiretrovirals – ritonavir, efavirenz and nevirapine
St John’s Wort
What types of contraception should be used in those using enzyme-inducing drugs?
IUS
IUD
Progestogen-only injection
(COCP with 50ug of ethinylestradiol can be considered. Continuous or tricycled with HFI 4/7 - should be advised effectiveness not guaranteed, increased VTE risk, excluding when using rifampicin or rifabutin as these are particularly potent enzyme inducers)
Is topiramate an enzyme inducer?
Should be treated as an enzyme-inducer AND a teratogen
Is sodium valproate an enzyme inducer?
No, JUST a teratogen
What are the contraceptive options when a patient is taking topiramate (inducer and teratogen)?
Cu-IUD
LNG-IUD
Progestogen-only injection + condoms
What is the top choice EC in someone using enzyme-inducing drugs?
Cu-IUD
If a patient taking an enzyme-inducer were to refuse a Cu-IUD for EC, what would be the next best option?
Double dose levonorgestrel (3mg)
Can diaphragms be used when menstruating?
No
How long after childbirth should a women wait before being fitted for a diaphragm?
6 weeks
When using contraceptive injectables, what is the minimum frequency a patient needs to be reviewed by a prescriber?
24 months
Where are ethinylestradiol and progestogen absorbed when taken orally?
Small intestine
At what weight may the CHC patch be less effective?
> 90kg
How often are norethisterone enantate injections given?
IM, 8-weekly
What is the window-period for taking Zoely (non-phasic estradiol pill)?
12 hours
Can a Mooncup be used with a coil?
Yes - but evidence suggests that there could be increased risk of expulsion associated with menstrual cup use. With many different brands available, users should be advised to follow the manufacturer’s instructions, including any special considerations for IUC users
What are the 2 major classes of synthetic progestins?
C19-nortestosterone progestins
C21 acetoxy progestins
Which class of progestin is structurally related to testosterone?
C19-nortestosterone progestins
Which class of progestin is structurally related to progesterone?
C21 acetoxy progestins, e.g. medroxyprogesterone acetate
What are the conditions of LAM?
- <6/12 PN
- Amenorrhoea
- Fully breast feeding
What is the definition of ‘fully breastfeeding’?
- Breastfeeding occurs day and night
- The infant does not receive other liquids/feeds, with the exception of occasional water, juice or vitamins given infrequently in addition to breastfeeds
- Intervals between feeds during the day do not exceed 4 hours
- Intervals between feeds during the night do not exceed 6 hours
What factors may increase the risk of pregnancy in LAM?
- Stopping night feeds
- Increasing supplementary feeds
- Use of dummies/pacifiers
- Expressing milk
What is the physiology behind LAM?
Mechanoreceptors in the breast alveoli stimulate prolactin and oxytocin (activating milk release) release from the pituitary
Prolactin stimulates milk production and disrupts GnRH release
Suckling disrupts GnRH pulsatility leading to reduced LH release by the anterior pituitary
This prevents the LH surge and inhibits ovulation
FSH is still released resulting in variable levels of follicular activity, however reduced LH levels impedes oestrogen synthesis
An incidental finding of what organism on HVS should lead to immediate treatment, especially if pre- IUS/IUD fit?
GAS
What are the potential sequalae for GAS infection?
- Life-threatening septicaemia
- Necrotising fasciitis
- Toxic shock syndrome
What is the effect of COCP on breastfeeding?
Better quality studies of early initiation of CHC found no adverse effects on either breastfeeding
performance or infant outcomes
Until when should CHC be avoided in those with recurrent early miscarriage?
Until APS is ruled out
What is the true failure rate with the implant?
0.05%
What nerve is most commonly damaged by implant insertion?
Ulnar nerve
When is ovulation inhibition achieved with etonogestrel (ENG) implant?
When serum etonogestrel ≥90 pg/ml (normally occurs within 1 day of insertion)
What is the ENG release with the implant at weeks 5-6?
60-70 μg/day
What is the ENG release with the implant at 12 months?
35-45 μg/day
What is the ENG release with the implant at 3 years?
25-30 μg/day
What is the size of the contraceptive implant?
4cm, 2mm wide
What does the contraceptive implant contain?
An ethylene vinyl acetate
copolymer skin and core, a core of 68 mg ENG (the active metabolite of desogestrel, a
19-nortestosterone derivative) and barium sulphate for radio-opacity
When is peak ENG reached after implant insertion?
2 weeks after insertion
Why a bleeding patterns unpredictable with the contraceptive implant?
The endometrial glands, stroma and vasculature are continuously exposed to progestogen and, at the same time, fluctuating levels of estrogen resulting from incomplete ovarian suppression. It is thought that this disturbs endometrial angiogenesis, resulting in thin-walled, distended, fragile superficial microvessels that bleed easily when subjected to minor stretching stresses.
Progestogen exposure may cause the covering surface epithelium to detach from the underlying stroma, allowing subepithelial bleeds to become overt. Epithelial repair mechanisms may be defective, permitting light bleeding to persist
What proportion of women have amenorrhoea with the contraceptive implant?
Amenorrhoea was recorded by 25% of ENG-IMP users at 6 to 9 months after insertion, declining thereafter to 12% by 3 years
How does Ethyl chloride spray work for anaesthetic for implant insertion?
Vapocoolant that by cooling the skin and reducing impulses in
local sensory nerves produces a local anaesthetic effect of rapid onset but short duration of action (60s)
What plt count is suitable for implant insertion/removal?
> 50
What frequency of US should be used when locating deep implants?
10 MHz or greater
What does the Jadelle contain, and how long does it last for?
LNG, 5 year license
What does the Sino-implant (II) contain, and how long does it last for?
LNG, 4 year license