Lecture 18: Avoiding Pregnancy Contraception Flashcards
What is the legal age of consent?
16 but studies show that up to 30% of NZ teenagers have had sex before 15
What is contraception?
A method of preventing pregnancy via interference with ovulation, fertilisation or implantation
Around what day after fertilisation does the egg implant?
Day ~8
How do you calculate the date of ovulation
Count backwards from the period
Day 14 in 28 day cycle
Day 16 in 30 day cycle
Day 12 in 26 day cycle
What are the characterisitics of the “perfect” contraceptive
1) 100% effective
2) 100% convinient
3) 100% safe
4) 100% reversible
5) Maintenance free
6) Non contraceptive benefits
7) Inexpensive
8) Acceptable to the user
What is the UK MEC?
Medicine eligibility criteria
Evidence based guidance for providers of contraception
MEC 1: No restriction on use
MEC 2: Advantages of use of method generally outweight the disadvantages
MEC 3: Disadvantages of use generally outweigh the advantages
MEC 4: Do not use under any circumstances
What are the stats of effectiveness of different types of contraception?
What is the difference between perfect use and typical use?
Perfect use = never miss an appointment, always take on time etc.
Typical use = What people usually use
Bit disparity. The perfect use is very different to perfect use
IUD and implant are the only ones that have similar rates between perfect and typical use.
Describe the Combined oral contraceptive pill
How do they work? (4)
1) Suppress ovulation ** main action
2) Reduce sperm transport in upper genital tract (fallopian tube)
3) C_hange endometrium_ making implantation less likely
4) Thicken cervical mucus (preventing sperm penetration)
What are the advantages and disadvantages of the Combined oral contraceptive pill?
Advantages
- Available everywhere
- Trusted
- Everyone knows about it
- Can stop whenever you want
- Has non-contraceptive benefits (e.g. reduces ovarian cancer and endometrial cancer)
Disadvantages
- 9% failure rate
- Complicated to take (mis-pill rules are complex)
- Lots of reasons why people can’t take it (especially older patients who smoke or BMI
How does the Combined oral contraceptive pill work?
The estrogen in the pill overrides the hormone cycle needed in an ovulation (e.g. no LH surge)
The combined oral contraceptive pill (usually just called the pill) contains both oestrogen and progestogen.
If someone comes in asking for the Combined oral contraceptive pill, what should you ask them?
If they suffer from focal migrains
History
Smoking
Weight
Epileptic
BP
Why now?
Already sexually active? Have they used other contraception?
Menstrual cycle
STI risk assessment
Stress advanges, dicuss any preconceptions
Missed pill instructions
What happens during the pill-free interval?
In the pill-free interval (the 7 days), the estrogen is being withdrawn and FSH increases
The LH surge is triggered- Ovulate
The most risky time to miss a pill is during the first week after the 7-day break. If you miss a pill in this time and have had sex, you have a higher risk of getting pregnant and may want to consider the emergency contraceptive pill.
If you miss a pill during days 7 to 14, you are less likely to get pregnant. Seek help if you are worried about missing a pill.
If you miss a pill in the third week, you are unlikely to get pregnant, but you must skip the 7-day break and go straight to the first active pill in the next packet
When people start the pill (OCP) are they protected straight away?
D1-5 of cycle, they are protected straight away
If they start later in the cycle (and reasonably sure they’re not pregnant- no sex since the last cycle)- they need to take 7-day precautions
(no interaction with antibiotics- expect rifampicin, which is rarely encountered)
How does the POP pill work?
Progesterone only pill
Take every day
Mainly works by thickening the cervical mucus.
This effect is maximal 48 hours after starting the POP
Funded POP has only a small window of opportunity- relying on the cervical mucus effect
When would we use POP?
Progesterone only pill
Useful if unable to take OCP or if they’re breastfeeding
Funded POP has only a small window of opportunity- relying on the cervical mucus effect
Cerazette has a much lower failure rate due to its suppression of ovulation and a 12-hour window but it’s unfunded
Describe LARC
Definition
Benefit
NZ related issues
Long acting reversible contraception
Definition: requires administration less than once per month
Benefits: cost effective even after 1 year of use
NZ related issues: training and accessibility (including cost)
Describe DEPO
(advantages, disadvantages)
Depo Provera is a contraceptive injection containing progestogen. It is commonly referred to as “the injection” or “DP”.
Progestogen is similar to one of the hormones produced naturally by a woman’s ovaries. The injection is given every 12 weeks.
- 12 weekly injection
- Prolonged amenorrhoea, weight gain
- Delayed return of fertility
- Oestrogen free- fewer restrictions than the OCP
How does the DEPO work?
Depo Provera is a contraceptive injection containing progestogen. It is commonly referred to as “the injection” or “DP”.
Progestogen is similar to one of the hormones produced naturally by a woman’s ovaries. The injection is given every 12 weeks.
Supresses hormones responsible for ovulation
Thickens cervical mucus to block sperm
What is Jadelle?
The implant or “the rods” are a type of long-acting reversible contraception (LARC).
Implanted into inner aspect of upper arm
Lasts 5 years
Some problems with bleeding (14%) but high satisfaction rate
How does the jadelle work?
1) Prevents ovulation
2) Alters endometrium (makes it thin so nothing can implant)
3) Thickens cerval mucus
Describe copper IUD
The IUD is a type of long-acting reversible contraception (LARC) that goes in your uterus.
An IUD is a small, T-shaped object that goes inside your uterus.
- There are two types of IUDs:
- Copper IUD - contains copper, a type of metal
- Hormonal IUD – contains the hormone progestogen (Mirena or Jaydess)
Lasts 10 years
Can cause periods to be heavier and/or more painful
Cheap
How do IUD-copper work?
An IUD is a small, T-shaped object that goes inside your uterus.
- Inserted via the cervix to sit in the uterus
- The copper is directly spermatoxic so fertilisation does not take place
- It also creates an _inflammatory reactio_n in the endometrium so that implantation does not work
- Very very effective
- Can be used as post-coidal contraception
- No need to swab pre-fit: take a sexual history and assess the risk
- Gold standard for emergency contraception
Describe Mirena IUS
It is an IUD which releases a progestogen hormone to stop conception and help reduce heavy periods.
A significant advantage of Mirena is that it usually reduces blood loss during menstruation by up to 75 percent
Not funded in NZ as contraception
How does the mirena work?
1) Make endometrium thinner
2) Creates unfavourable environment for the sperm in the uterus and the fallopian tubes so fertilisation is prevented
3) Makes cervical mucus thicker so that sperm passage is obstructed
What are the indications for Mirena?
1) Heavy menstrual beleeding
2) Contraception
3) Endometrial protection with HRT (Hormone replacement therapy)
Also used to decrease dysmeorrhoea, m_ild endometriosis,_ and endometrial hyperplasia
Describe the emergency contraception
Licenced up to 72 hours following UPSI
Efficacy decreases with time (85% at 72 hours)
Main action is to postpone/prevent ovulation. Postpones ovulation for 5 days (how long sperm lasts) by which time no active sperm in the genital tract
At/after ovulation, effect is no better than placebo. (so find out their menstural cycle)
IUD-copper is a better option.
Describe Cooper IUD as an emergency contraception
Copper IUD can be used up to _5 days after ovulation (_D19 of a 28 day cycle)
(because implantation occurs at day 8, so we know that as long as we can say that it’s within 5 days, you are not terminating a pregnancy)
Weight is not a factor
Anti implantation and (primarily) anti fertilisation effects
Provide on-going contraception
