Contraception Flashcards
Explain the MOA of CHC.
Inhibition of ovulation
Changes to cervical mucus (mechanical barrier to sperm penetration)
Endometrial changes (stimulates endometrial growth but progestogen counteracts this by preventing excessive thickening leading to a thin, fragile endometrium and reducing implantation.
What are the types of hormone components? (2)
Oestrogen
Progestogen
What are the types of COC based on hormone dosing?
Monophasic (first line)
Phasic (biphasic/triphasic/quadraphasic)
What are the types of oestrogen strengths?
Low (20mcg ethinylestradiol)
Standard (30-35mcg ethinylestradiol)
High (50mcg mestranol)
What are the 2 main types of dosing regimens for CHC?
21/7 standard: 21 active pills, 7 days pill free period = withdrawal bleed.
ED (every day): 21 active pills, 7 placebo = continuously daily dosing to aid compliance.
Give e.g. of special preparations for CHC.
Qlaira (Quadriphasic) - continuous 28 day regimen for heavy menstrual bleeding.
Dianette (Co-cyprindiol) - used for acne/hirsutism, carries higher VTE risk, not recommended for contraception.
Zoely (Monophasic) - contains Estradiol (natural oestrogen) and nomegestrol acetate.
Explain how COC is initiated.
Day 1 up to and including day 5 of menstrual cycle:
- No additional contraception is required.
- Ideally start on day 1.
Day 6 on menstrual cycle onwards:
- Additional precautions are required for 7 days after starting (9 days for Qlaira)
Additional advice:
- Ideally should take pill at the same time each day.
What are the 5 main types of monophonic COC dose regimens?
Standard use = 21 active pills, 7 day free period.
ED = 21 active pills, 7 day placebo pills.
Shortened hormone-free interval = 21 active pills, 4 days pill free period.
Extended use (tri-cycling) = 9 weeks (3x21 active pills), 4 or 7 day pill free period.
Flexible extended use = continuously daily dosing use >= 21 days) of active pills until breakthrough bleeding occurs for 3-4 days. 4 days pill-free interval.
Continuous use = continuously use of active pills.
Explain the missed pill rules for COC.
Missed COC pill = > 24 hrs late.
Effectiveness of CHC is highly dependent on correct and consistent use.
- If used perfectly (consistently and correctly), the risk of CHC contraceptive failure is low.
- If used typically, failure rate = 9%.
Actions for missed COC is dependent on:
- When contraception has been missed i.e. time since last active pill was taken.
- How many pills the px has missed.
- Where they’re in cycle (pack)
- Which pill the px is taking
If 1 active pill is missed (> 24 hrs and up to 48 hrs late) , no additional precautions are needed. Continue contraceptive coverage. Missed pills to be taken as soon as it’s remembered. The remaining pills should be continued at usual time. Even if taking 2 pills in 24 hrs. Reduces risk of pregnancy.
If 2 or more active pills are missed >= 48 hrs late: Additional precautions should be taken for the next 7 days.
If missed pills early in the cycle or at the end which extends the hormone free interval, this increases pregnancy risk. Missing multiple pills also increases risk of pregnancy. If > 7 active COC pills have been missed, restart cycle.
Week 1: (Pills 1-7):
- No EHC is needed if pills earlier in the week and during the HFI were consistent.
- If UPAI occurred in the past 7 days or adherence is uncertain then consider EHC.
Week 2: (8-14) & 3 (Pills 15-21)
- No EHC is is needed if previous 7 days of pills were taken correctly.
If 2 or more (max 7) active pills are missed > 72 hrs late:
- Continue contraception cover.
- Take most recently missed pills ASAP.
- Continue remaining pills at the usual time.
- Condoms should be used or sex avoided until pills have been taken for 7 consecutive days.
Week 1 (Pills 1-7):
- Consider EC if UPSI has taken place during HFI or eek 1.
Week 2 (8-14):
- No EHC needed if previous 7 days were correct.
Week 3: (15-21):
- In 7 days prior to a schedule HFI, omit the HFI and start new pack immediately.
What are the key risks with CHC?
VTE
ATE (Stroke/MI0
Migraine with aura
HPT
Breast cancer
Cervical cancer
Age (> 35yrs and smoker, avoid > 50yrs)
What are the common s/e of CHC?
Breakthrough bleeding
Weight gain
Mood changes
What factors affects the efficacy CHC?
Vomiting and diarrhoea:
- If vomiting occurs within 3 hrs of taking pill, take another pill ASAP:
- If vomiting or severe diarrhoea occurs > 24 hrs:
- Follow instructions of missed pills, counting each day of vomiting/diarrhoea has a missed pill.
- Avoid coitus or use a barrier method of contraception (e.g. condoms) during illness interval and for 7 days afterwards.
- If illness occurs while taking last 7 tablets, omit any pill-free period (or inactive tablets), start the next cycle immediately.
What are the common interactions with CHC? (3)
Enzyme inducing drugs e.g. carbamazepine, St John’s Wort:
- Switch to IUS/IUD or depot.
- If continue with COC: Use 50mg COC with continuous/tricycling regimen.
- Use barrier method for 28 days afterwards.
Enzyme inducing ABx e.g. Rifampicin, Rifabutin:
- Short term tx (< 2 months): Alternative method or barrier method e.g. condoms while on ABx and for 28 days after stopping.
- Long-term tx (>2 months): Switch to alternative method of contraception (IUD, IUS, Depo)
Lamotrigine: Avoid COC if possible, switch to IUS, IUD or Depo. If unavoidable, increase dose of Lamotrigine 2x and use COC continuously to avoid cyclical fluctuations .
What are the cautions and c/i of CHC?
Severe/multiple risk factors for arterial disease.
VTE
Migraine with aura.
Smoker >.= 15 cigarettes per day and >= 35 yrs.
What are the risk factors of CHC?
1st degree relative < 45 yrs with Hx of VTE
BMI >= 35
Smoker < 15 cigarettes/day or stopped in last year and >= 35 yrs.
Symptomatic gall bladder disease
Adequate controlled HPT
Diabetes with nephropathy, retinopathy, neuropathy.
Explain the MOA of POC.
Alters cervical mucus (more viscous and impnetrable to sperm)
Alternation of endometrial lining
Suppression of ovulation
What are the 3 main preparations of POP?
Desogestrel only pill - 1 taken daily continuously without a break, 12 hr window for missed pills, desogestrel 75 mcg = Cerazette, Aizea, Cerells and Nacrez.
Given first line in < 35 yrs old, if compliance issue with taking traditional POP.
Traditional POP: (less used) - 1 to be taken daily continuously without a break, 3 hrs window for missed pills e.g. Norethisterone 350mcg - Micronor/Noriday, Levogestrel 30mcg - Norgeston.
Slynd - Drospirenone 4mg POP: 24 hrs window for missed pill. 24 consecutive daily 4mg drospirerone pills followed by 4 inactive pills ( 4 day hormone free interval). Spironolactone derivative - an aldosterone antagonists with anti androgenic activity. Acts primarily to suppress ovulation, with additional contraceptive effects on cervical mucus and endometrium.
Advantages: More predictable bleeding patterns, less s/e, antiandrogenic so useful in PCOS/Acne.
What px factors is considered for choice of contraceptive?
Older women (up to 55 yrs)
Hx of VTE
Smokers
HPT
VHD
Diabetes
Migraine sufferers
Breastfeeding
What is common s/e of POP?
Unscheduled bleeding:
Explain the process of starting POP.
Day 1 up to and including day 5 of menstrual cycle:
- No additional contraceptive protection required.
- Start on day 1 menstrual cycle.
Day 6 of menstrual cycle onwards:
- Additional precautions required, condoms or abstinence is required for 2 days.
What is the missed pill rules for POP?
POPs should be taken every 24 hrs.
Less than 12 hrs late (3 hrs traditional):
- Take late or missed ASAP.
- Continue taking the remaining pills at the usual time (even if taking 2 pills on the same day).
- No additional contraceptive protection is needed.
> 12 hrs late (3 hrs for traditional):
- Take most recent missed pills ASAP. Any other missed pills should be discarded.
- Continue taking remaining pills at usual time (even if taking 2 pills on the same day)
- Use additional contraception (or abstain until pills have been taken for 2 consecutive days.
What are the c/i of POP?
Breast cancer
What are the risk factors of POP?
Hx of breast cancer.
Severe cirrhosis
Liver tumours
Stroke + CHD
SLE with positive antiphospholipid ABx.
Those on medication, including antiretroviral therapy, enzyme-inducing anticonvulsants (not including Lamotrigine and enzyme inducing ABx e.g. Rifampicin, Rifabutin)
Explain the process of managing diarrhoea and vomiting when taking POP.
If vomiting occurs within 2 hrs of taking a pill then take another ASAP:
- If subsequent pill is taken > 3 hrs later or 12 hrs for a Desogestrel pill, follow missed pill rules.
If vomiting or severe diarrhoea occurs > 24 hrs advise:
- Follow instruction for missed pills, counting each day of vomiting +/or diarrhoea as a missed pills.
- Avoid coitus or use barrier method of contraception (condoms) during illness interval and for 2 days afterwards.
Give e.g. of common interactions with POP.
Enzyme inducing drugs (Carbamazepine, St. John’s Wort) + Enzyme inducing ABx (e.g. Rifampicin, Rifabutin) = ST tx (< 2 months) Alternative method or use barrier method e.g. condoms and for 28 days after stopping. LT tx (> 2 months), switch to alt methods of contraception (IUD, IUS and Depo)
Lamotrigine: Progestogens can decrease serum Lamotrigine. If unavoidable, aware of signs of Lamotrigine toxicity. Monitor serum Lamotrigine if progestogen stopped.
Define LARCS.
Long-acting Reversible Contaceptives
Explain the main features of depot medroxyprogesterone acetate.
Not for < 18 yrs.
May reduce BMD
Via injection every 3 months.
Highly effective (99%)
Delays fertility return
Weight gain = s/e
Syanopress - given to px to self-administer.
Explain the main features of Etonogestrel (Nexplanon implant)
Lasts for 3 yrs.
Insertion under the skin in the upper arm.
Effectiveness: low failure rate.
Irregular bleeding = s/e
Explain the main features of progestogen-only IUS.
Levogestrel Intrauterine system: Releases LNG directly into the uterine cavity.
E.g. jaydess, levosert, Mirena and Kyleena
Effective up to 5 yrs except for Jaydess - 3yrs.
Low failure rate
Irregular bleeding and spotting = s/e in first 6 months often amenorrheoic after 1 yr.
Normal fertility returns as soon as the device is removed.
Explain the main features of copper IUD.
Non-hormonal intrauterine device containing copper:
- Inhibits fertilisation/implantation.
Key points:
- Ongoing/emergency contraception. (1st line = EHC)
- No hormonal s/e
- Heavier bleeding and/or dysmenorrhoea.
- Duration of action from 5-10 yrs.
- Failure rate < 1%
Explain the main features of contraception during teratogenic use.
Failure rate <1%
PPP should be in place to prevent risk of conception.
Teratogens that aren’t enzyme inducers.
Implant, IUS:
- If using CHC, POP or depot , condoms should be used as well.
Teratogens that are enzyme inducers:
- Topiramate at higher doses
- Cu-IUD, levonorgestrel-releasing IUS, or depot medroxyprogesterone acetate PLUS condoms.
- COC’s, POPs and Etonogestrel implants aren’t recommended with enzyme inducers.
Explain the use contraception for trans men.
Assigned female at birth
Contraception is needed if no hysterectomy or bilateral oophorectomy.
Testosterone therapy not reliable for contraception.
Testosterone = teratogenic, especially for female foetuses.
Contraceptive Options:
- Cu-IUD: Safe but may cause unpredictable bleeding.
- Progestogen-only contraception: Don’t interfere with hormone regimens. (Depot injection + LNG-IUS = reduces or stop vaginal bleeding.)
- CHC = not recommended as oestrogen counteracts masculinisation.
Explain the use of contraception for trans women.
Assigned male at birth.
Risk of pregnancy if no orchidectomy or vasectomy.
Estradiol therapy not a contraceptive despite impairing spermatogenesis.
GnRH analogues, Finasteride and cyproterone acetate = unreliable for contraception.
Contraceptive option:
- Condoms (Non-permanent but has high failure rates)
- Vasectomy (permanent contraceptive option.)
