Contraception: Ovulation- Working around it Flashcards
Some basic fertility principles
Days of ovulation: 14 days before next period starts Sperm survival: Max 7 days Typical sperm count in ejaculate: 350 million Egg survival: 12-24 hours Calendar method: 28 day cycle Fertile phase: days 7-16 Peak fecundity: week before ovulation can get preggers on period
How can temperature be a good indication of ovulation?
Using a good thermometer, can measure a small change in temp on ovulation (0.2-0.8 degrees)
Due to progesterone a day post ovulation.
Infertile after third evening of temp rise
3/6 rule
How can checking mucus be a good indication of ovulation?
Half a day to 4 days prior to ovulation, fertile mucus is present (high spinbarkeit).
Ovulation causes dryness, so peak mucus day is prior to this.
Infertile 4 days after this day
Lactational amenorrhea
No period return for up to six months when breast feeding day and night.
No supplements also
Good contraceptive
Failure rate for adolosecents using the pill
Higher than normal, about 30% due to more technical problems
Combined oral contraceptive pill:
How is it taken
What is in it
Do you need Rx
Taken daily, starts with a low dose pill of estrogen (estradiol).
Then a 2nd generation progestogen like levonorgestrel or norethisterone. (note these are good as lower deep vein thrombosis risk)
Use some third gen sometimes but higher DVT risk. However better than other pills
No prescrption needed now if seen in last three years with initial prescription
Why are there some high dose oestrogen pills funded?
Some other drugs, enzyme inducers (e.g anti-epileptics) break down the pill very quickly
What is important when taking the COCP with timing and what not?
How to follow up
also these hormones increase SBG thus less free testosterone, less acne
Purpose is FSH suppression, preventing ovulation.
If you miss 2 hormones in a row (or take them 12 hurs after normal time) or vomit within 3 hours of taking 2 pills, may be at risk.
This is because in the 7 week period off hormones, and FSH is less suppressed, if you miss two days, especially in that first week, FSH might not be as suppressed and cause ovulation. Missed in 2nd and 3rd weeks is okay typically
7 day rule where you do not have sex or use condoms to let ovaries readjust. Can be encouraged to take continuous hormones
How does the ECP work and when is it given?
It is a high dose progestogen (levonorgestrel).
Works by delaying ovulation. DOES NOT WORK if ovulation has occurred.
Best taken within 3 days of unprotected sex.
If BMI > 30 do not use
What is a post coital IUD
Use within 5 days of ovulation, Will prevent implantation (knowing 7 days post fertilisation to implant)
BMI above 30
How does the low dose progestogen pill work?
How does depo provera work?
How does the IUD work?
Low dose progesterone tpo thicken cervical mucus
High dose progestogen to prevent ovulation, IM injection.
IUD (copper) is a spermicide. Note can cause cramping and heavy periods. Can be used at any age, however STI risk should be evaluated
Mirena
Like a copper IUD that produces progestogen to reduce menstrual bleeding.
Is only subsidised for heavy menstrual bleeding, not contraception
What is the other type of LARC other than the IUD?
Implants, in NZ, Jadelle (in arm) Funded product ($5) that prouduces progesterone. Prevent ovulation in most cycls and useful for dysmenorrhea. Not effective with enzyme inducers.
Side effect is spotting
Nuva ring
Stops ovulation and produces oestrogen.
Ring in for 3 weeks, and can take out for a week. Can be out for less than 3 hours.
Crap with liver induced enzymes
