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
What does the Norplant contain, and how long does it last for?
LNG, six rod device, 5 year license
What is the failure rate (perfect and typical) with the Cu-IUD?
Perfect use - 0.6%
Typical use - 0.8%
What if the failure rate of the IUS?
52mg - 0.2% (typical and perfect)
13.5/19.5mg - 0.2% (typical and perfect)
What is the prevalene of non-visible threads?
Standard IUC insertion - 18%,
IUC insertion within 48 hours of VD - 30%
IUC at CS - 50%
How long is gynefix licensed for?
5 years
Which copper IUDs are suitable for cavities of only 5cm?
Mini TT380® Slimline (banded) - 5 years
UT380 Short (unbanded) - 5 years
Novaplus T 380® Cu
‘mini’ (unbanded) - 5 years
What is the silver IUD?
Novaplus T380® Ag - available in standard and mini sizes, 5 year license
Which IUS have blue threads?
Benilexa
Levosert
Kyleena
Which IUS have brown threads?
Mirena
Jaydess
Which IUS have a silver ring for better visibility on US?
Kyleena
Jaydess
What is the LNG release rate with Benilexa, Levosert, Mirena?
Initial - 20-20.1mcg/24h
End of license - 8.6-9mcg/24h
What is the LNG release rate with Kyleena?
Initial - 17.5mcg/24h
End of license - 7.4mcg/24h
What is the LNG release rate with Jaydess?
Initial - 14mcg/24h
End of license - 5mcg/24h
What proportion of women with the IUS continue to ovulate?
> 75%
What is the prevalence of congenital uterine anomalies?
3-4%
If immediate replacement of an IUD is not done at time of LLETZ, how long should you wait for healing for replacement?
4-6 weeks
What advice should those with adrenal insufficiency follow prior to coil insertion?
- Procedure scheduled for early morning
- Individuals at risk of an adrenal crisis will usually need to increase their steroid dose prior to, and for 24 hours after
What is the risk of a vasovagal during an IUS fit?
2%
How should someone taking warfarin be managed in relation to an IUC?
If <3.5, okay, but consider INR within 72 hours of procedure
What is the reported amenorrhoea rate at the end of license duration of the IUS?
11%–12% of 13.5 mg users
23% of 19.5 mg users
42% of 52 mg users
What factor may be associated with more bleeding with the IUS in the first 12 months?
Larger uterine cavity
Which IUC devices are NOT safe with MRI?
Chinese ring
At what Tesla are copper IUD, Kyleena and Jaydess safe in MRI?
1.5 Tesla (T) or 3 T
What proportion of IUC is malpositioned?
7% and 19%
An IUC what distance from the top of the endometrial cavity is considered too low?
> 2cm
How can bradycardia come about with an IUC fit?
M2 receptors at the SA node are activated by acetylcholine via parasympathetic nerves (i.e. the vagus)
This decreases the rate of action potentials generated by the SA node and the conduction velocity through the AV node
This causes the heart rate to decrease (negative chronotropy)
How does atropine improve bradycardia following IUC fit?
A non-selective muscarinic antagonist
Inhibits parasympathetic activation of cardiac M2 receptors
SA node firing and conduction through the AV node is increased
This leads to an increase in heart rate (positive chronotropy)
For how long after vasectomy should one abstain from sex?
2 to 7 days post-procedure
What is the timing recommendation for the PVSA?
12 weeks after vasectomy
What proportion of men should be azoospermic 12 weeks post vasectomy?
80%
What are the attrition rates with PVSA?
14.0% to 46.2%
When non-motile sperm persist in the PVSA, when can contraception cease to be used?
When <100 000 non-motile sperm/ml are observed in a fresh semen sample post-vasectomy
When should the vasectomy be considered a failure?
If motile sperm are observed in a fresh sample 7 months post-procedure
What proportion of men have congenital absence of vas deferens?
<1%
If a vas deferens can not be palpated or found on one side, consider what?
Possibility of ipsilateral renal agenesis and refer for USS. May carry out unilateral vasectomy
What should be done if a bilateral absence of vas defences is suspected?
Refer to urology
What should be done if a double vas deferens is suspected?
Doppler ultrasound should
be used to determine whether it is a ‘true’ double vas or an ectopic ureter
What patency rate/pregnancy rate is experienced with a vasectomy reversal, performed within 3 years?
Patency - 97%
Pregnancy - 75%
What patency rate/pregnancy rate is experienced with a vasectomy reversal, performed within 19 years?
Patency - 40%
Pregnancy - <10%
What is the failure rate with perfect vs. typical use of the contraceptive injection?
Perfect use - 0.2%
Typical use - 6%
What predicts weight gain with the contraceptive injection?
Women who gain more than 5% of their baseline body weight in the first 6/12 of DMPA use are likely to experience continued weight gain
If they have a BMI >30 and under 18 at the time of initiation
What is the earliest interval norethisterone enantate can be given?
6 weeks
With what cancer is there a weak association with DMPA?
Cervical cancer - with DMPA use > 5 years (also the case with CHC)
What are the missed pill rules for the DRSP POP?
24 hours = missed
When is the contraceptive effect of the DRSP POP restored?
7 days
What is the time until unaffected by vomiting with the POP?
DRSP 3-4 hours
LNG 2 hours
DSG 3-4 hours
If trekking at what altitude for >7 days should a women be advised to switch away from CHC?
4500m/14500ft
How many weeks before a planned op in which there will be a prolonged period fo reduced mobility should a woman come off her CHC?
4 weeks
What is the DVT risks with levonorgestrel, norethisterone or norgestimate containing preparations?
5-7/10,000
What is the DVT risks with etonogestrel or norelgestromin containing preparations?
6-12/10,000
What is the DVT risks with drospirenone, gestodene or desogestrel containing preparations?
9-12/10,000
What is the rate of VTE in non-CHC users?
2/10,000
Of those that have a VTE on CHC, what proportion are fatal?
1%
What is the first generation progestogen?
Norethisterone (NET)
What is the second generation progestogen?
Levonorgestrel (LNG)
What are the third generation progestogens?
Desogestrel (etonogestrel is the active metabolite of DSG), gestodene, norgestimate (norelgestromin is a metabolite of norgestimate)
What are the newer/4th generation progestogens?
DRSP, dienogest, nomegestrol acetate
What does the patch contain?
33.9μg EE and 203μg
norelgestromin per 24 hours
What does the vaginal ring contain?
EE and etonogestrel at daily rates of 15μg and 120μg, respectively
Up to what age could the CHC be used?
50 - then the risk starts to outweigh the benefit
How may oral CHC affect thyroxine requirement in hypothyroidism?
May increase the requirement for thyroxine by increasing
thyroid binding globulin - check TFTs 6 weeks after CHC initiation
What is the interaction between CHC and lamotrigine?
Estrogen in CHC induces glucuronidation of lamotrigine,
reducing serum lamotrigine levels
If CHC use may need to increase lamotrigine dose (as much as double), monitor lamotrigine level and avoid the HFI to prevent lamotrigine toxicity
What is the interaction between POP and lamotrigine?
Oral DSG (evidence re: other POP v. v. limited) may increase exposure to lamotrigine, and therefore pt should monitor for lamotrigine toxicity - dizziness, ataxia, diplopia + monitor lamotrigine levels
What is the minimum recommended time interval between consent for sterilisation and elective caesarean section?
2 weeks
