Menstrual Cycle : Contraception Flashcards
What is the mechanism of action for the male condom?
Barrier.
What is the typical-use efficacy of male condoms?
18% experience unintended pregnancy after 1 year.
What is the mechanism of action for the copper intrauterine device (Cu-IUD)?
copper ions prevent fertilisation by immobilising sperm and inactivating lytic enzymes required for the acrosome reaction. Localised endometrial inflammation can prevent implantation even if fertilisation does occur
What is the typical-use efficacy of the Cu-IUD?
0.8% experience unintended pregnancy after 1 year.
The copper intrauterine device is immediately effective upon ______.
insertion.
Name three advantages of the Cu-IUD.
- Immediately effective upon insertion. 2. No hormonal side effects 3. High efficacy
List the absolute contraindications for Cu-IUD use.
- PID 2. Gonorrhoea or chlamydia 3. Unexplained vaginal bleeding / endometrial cancer 4. Postpartum / post-abortion septicaemia 5. Gestational trophoblastic disease 6. Purulent cervicitis, pelvic TB
What are common side effects of the Cu-IUD?
Breakthrough (intermenstrual) bleeding, increased duration / heaviness of periods
With a Cu-IUD, if pregnancy occurs, it is more likely to be ______.
ectopic.
What contraceptives are classed as LARC (long-acting reversible contraceptives)?
Cu-IUD. LNG-IUS (levonorgestrel intrauterine system).
Implant.
Injection.
How long can a Cu-IUD be left in situ?
5 years.
What is the mechanism of action for the combined hormonal contraceptive pill (CHC)?
progestogen component exerts negative feedback on hypothalamus, reducing GnRH release frequency and therefore suppressing secretion of LH and FSH. Oestradiol component exerts negative feedback on pituitary secretion of LH and FSH. Together, follicular development, the LH surge, and crucially ovulation, are all suppressed.
With typical use, ___% of CHC users experience unintended pregnancy after 1 year
0.09
With perfect use, the CHC annual failure rate is only ____%.
: 0.3%.
What does the efficacy difference between typical and perfect use of CHC highlight?
The importance of human error as a significant factor in effective contraception.
Name two advantages of the combined hormonal contraceptive pill (CHC).
- Rapidly reversible if unintended side effects 2. Regulates and tends to lighten periods.
What are the common side effects of CHC?
Headache, mood disturbance, and breakthrough bleeding.
What are the UKMEC 4 absolute contraindications for CHC?
- <6 weeks postpartum in breastfeeding women 2. Aged 35, smoking >15 cigarettes per day 3. Stage 2 hypertension (160/100) 4. History of VTE 5. Disease: Breast cancer, inherited thrombophilia e.g. Factor V Leiden, cardiomyopathy, cirrhosis, vascular disease, SLE, positive antiphospholipid antibodies. 6. Migraine with aura
What is the mechanism of the progesterone-only pill?
progestogen exerts negative feedback on hypothalamus, reducing GnRH release frequency and therefore suppressing secretion of LH and FSH. This suppresses follicle development, the LH surge, and ovulation. POPs also thicken cervical mucus to form a physical barrier to semen.
With typical use, ___% of POP users experience unintended pregnancy after 1 year
0.09
What are the advantages of the progesterone-only pill (POP)?
Rapidly reversible. Far fewer absolute contraindications than CHC.
What is the only absolute contraindication for POP use?
Breast cancer
What is a common side effect of the progesterone-only pill (POP)?
Breakthrough bleeding
The progesterone-only pill becomes effective after ____ days of administration.
2 days.
Mechanism of Levonorgestrel Intrauterine System (LNG-IUS)/ Mirena
thinning of endometrium by downregulation of endometrial oestrogen receptors; this prevents implantation. Does not inhibit ovulation
Efficacy of the Mirena
0.2% experience unintended pregnancy after 1 year
List four advantages of the LNG-IUS.
Extremely high efficacy. Can be left in situ for 3-5 years.
Lightens periods.
Minimal systemic absorption reduces systemic hormonal side effects.
What is a common side effect of the LNG-IUS?
Irregular menstrual bleeding.
Name the absolute contraindications for LNG-IUS use.
- PID 2. Gonorrhoea or chlamydia 3. Unexplained vaginal bleeding / endometrial cancer 4. Postpartum / post-abortion septicaemia 5. Gestational trophoblastic disease 6. Purulent cervicitis, pelvic TB
What is the mechanism of action for the contraceptive injection (Depo-Provera)?
progestogen exerts negative feedback on hypothalamus, reducing GnRH release frequency and therefore suppressing secretion of LH and FSH. This suppresses follicle development, the LH surge, and ovulation.
The typical-use efficacy of Depo-Provera is ___% unintended pregnancy after 1 year.
0.06
What is a key advantage of Depo-Provera?
Long-acting, requiring an injection every 13 weeks.
What is a common side effect of Depo-Provera?
Amenorrhea.
What is the absolute contraindication for Depo-Provera use?
Breast cancer
What is the mechanism of action for the contraceptive implant?
progestogen exerts negative feedback on hypothalamus, reducing GnRH release frequency and therefore suppressing secretion of LH and FSH. This suppresses follicle development, the LH surge, and ovulation.
The typical-use efficacy of the contraceptive implant is ___% unintended pregnancy after 1 year.
0.05%.
How does the contraceptive implant compare in efficacy to female sterilisation?
It has a 10 times lower frequency of unintended pregnancy than female sterilisation.
Advantages for the contraceptive implant
Most effective contraception available. - Active for 3 years before replacement is required.
Side effects of the contaceptive implant
Irregular menstrual bleeding
Absolute contraindications for the contraceptive implant
Breast cancer
What is the duration of activity for the contraceptive implant before replacement is required?
3 years.
What is the most effective contraception available?
The contraceptive implant.
What significant finding did a 2023 study reveal about progestogen-only contraceptives?
They increase the risk of breast cancer, similar to oestrogen-containing contraceptives.
What is the mechanism of action for the levonorgestrel emergency contraceptive pill?
exogenous progestogen, exerts negative feedback on hypothalamus to prevent the LH surge and delay ovulation in event of unprotected sexual intercourse (UPSI); can delay ovulation by 5 days (the viable lifespan of ejaculated sperm). Not effective in the late luteal phase, in which case ulipristal acetate is required.
Efficacy of the Levonorgestrel Pill
effective up to 72 hours post-UPSI - not effective if taken after ovulation has occurred.
How can the dose of Levonorgesteral Pill be changed dependent on the patient?
normal dose of 1.5mg can be doubled to 3mg if a woman is taking enzyme-inducing medications or has a BMI > 26.
Mechanism of Ulipristal Acetate Pill
selective progesterone receptor modulator, inhibits ovulation (possibly by blocking hypothalamic progesterone receptors, which studies suggest play a role in producing the LH surge).
Efficacy of the Ulipristal Acetate Pill
effective up to 120 hours post-UPSI. Unlike levonorgestrel, it can delay ovulation even if LH surge has started, which is why it remains effective in the late follicular phase. Not effective if taken after ovulation
Mechanism of Copper Intrauterine Device (Cu-IUD)
copper ions prevent fertilisation by immobilising sperm and inactivating lytic enzymes required for the acrosome reaction. Localised endometrial inflammation can prevent implantation even if fertilisation does occur.
Why is the Cu-IUD considered the most effective form of emergency contraception?
It prevents fertilization and implantation effectively and can be inserted up to 5 days post-ovulation, as implantation occurs on days 6-7 post-fertilization.
What are the contraindications for using a Cu-IUD for emergency contraception?
Same as for regular Cu-IUD insertion: PID, gonorrhea or chlamydia, unexplained vaginal bleeding, endometrial cancer, postpartum/post-abortion septicemia, gestational trophoblastic disease, purulent cervicitis, and pelvic TB.
The Cu-IUD is licensed for insertion within ___ days of ovulation as emergency contraception.
5
What is the first-line method offered for emergency contraception?
The Cu-IUD, as it is the most effective method.
When can the Cu-IUD be inserted for emergency contraception?
Within 120 hours of first UPSI or within 120 hours of the calculated date of ovulation, whichever is later.
What are the options if the Cu-IUD is not acceptable or appropriate for emergency contraception?
If within 72 hours of UPSI, offer levonorgestrel (LNG) or ulipristal acetate (UPA).If 72-120 hours post-UPSI, offer ulipristal acetate (UPA).
