Lecture 13: Contraception and infertility Flashcards
What are the methods of contraception?
Any method to prevent pregnancy
- block sperm transport to avoid fertilisation of the oocyte
- disruption of the HPG axis: interfere with ovulation
- inhibiting inplantation of conceptus into endometrium
What are the categories of methods of contraception?
- Natural
- Barrier
- Hormonal control
- Prevention of implantation
- Sterilisation
- Emergency contraception
What are the natural methods of contraception?
Abstinence
Pros: 100% effective
Cons: not an option for most, unprepared when they become sexually active
Withdrawal (coitus interruptus)
Pros: no devices or hormones
Cons: unreliable, some sperm in pre-ejaculate, no STI protection
Fertility awareness methods (monitoring and recording fertility indicators in cycle e.g. cervical secretions, changes in cervix, basal body temp, length of menstrual cycle)
Pros: no hormones/no contraindications
Cons: time-consuming, unreliable, no STI protection, not suitable for all
Lactational amenorrhoea method (breastfeeding after childbirth to avoid pregnancy, delays the return of ovulation by disrupting gonadotrophin release, can be used for 6 months postnatally provided exclusive breastfeeding and complete amenorrhoea)
Pros: no hormones/no contraindications
Cons: unreliable after 6 months, no STI protections, not suitable for all
What are some examples of barrier contraceptives?
Provide physical +/- chemical barrier to sperm entering the cervix
-male/female condoms
-diaphragms/cervical cups (used in conjunction with spermicides)
-spermicides
Pros: reliable if used correctly, STI protection
Cons: disrupts intercourse, risk of dislodging, allergy/sensitivity to latex
What are the options for hormonal control?
Interrupt HPG axis and prevent ovulation, may have effects on endometrial lining
-short-acting or long-acting reversible contraception (LARC)
- Combined oestrogen and progesterogen (COCP, patch, ring)
- POP (progestogen only pill)
- LARC (progestogen depot and implant)
What is progestogen?
Synthetic progesterone
What is the action of the COCP?
Taken 21 days with 7 day break
Main action: prevent ovulation (-ve feedback to HPG axis to prevent LH surge: continued levels of oestrogen and progesterone prevents LH surge, so the whole cycle is like the luteal phase, hence no ovulation)
Secondary action: reduce endometrial receptivity to implantation, thicken cervical mucous (due to high progesterone)
What are the pros and cons of the COCP?
Pros
-reliable if used correctly
-can relieve menstrual disorders
-reduced risk of ovarian and endometrial cancer (reduced frequency of disruption to ovaries as no ovulation, and by reducing proliferation of endometrium)
-reduces acne severity in some
Cons
-user dependant
-no STI protection
-medication interaction
-contraindications (can’t give it to people with) (raised BMI, migraines +aura, breast cancer)
-side effects: menstrual irregularities, breast tenderness, mood disturbance
-increased risk of CV disease, stroke, breast cancer, cervical cancer, venous thromboembolism
What is the action of the POP?
Low dose progesterone
-thickens cervical mucus (main action)
-reduced cilia activity in fallopian tubes (other action)
Ovulation is not prevented, as no oestrogen
Taken daily with no breaks
What are the pros and cons of the POP?
Pros -reliable if used correctly -can be used if COCP is contraindicated Cons -no STI protection -strict timing: user dependant -menstrual irregularities -increased risk of ectopic pregnancy (due to reduced action of the cilia in the fallopian tubes)
What is the action of the progesterone injection?
High dose progesterone (LARC) (Depo-provera)
-inhibits ovulation (while body is producing high levels of progesterone the body will not ovulate, due ot negative feedback from high levels of progesterone), thickens cervical mucus. thins endometrial lining
Given intramuscularly every 12 weeks
What are the pros and cons of the progesterone injection?
Pros -reliable -no known medication interactions -used if oestrogen is contraindicated and raised BMI Cons -no STI protection -not rapidly reversible -menstrual irregularities
What is the action of the progesterone implant?
Small subcutaneous tube inserted in the arm
- high dose progesterone (LARC)
- inhibits ovulation, thickens cervical mucus, thin endometrial lining
What are the pros and cons of the progesterone implant?
Pros
-reliable
-lasts for up to 3 years
-can be used if oestrogen is contraindicated and raised BMI
-fertility returns faster than with an injection
Cons
-no STI protection
-menstrual irregularity
-complications with insertion and removal
What are the different options of contraception which act to inhibit implantation?
Intrauterine system (IUS)
-progestogen releasing coil-local release
-prevents implantation, reduces endometrial proliferation, thickens cervical mucus
-ovulation usually continues as local release of progesterone so no effect on HPG axis
Intrauterine device (IUD)
-copper-containing coil
-copper is toxic to the ovum and sperm, preventing fertilisation
-cervical mucus changes, endometrial inflammatory reactions which inhibit implantation