Fertility and contraception Flashcards
1
Q
contraceptives
A
- Contraceptives = family planning/birth control methods
- Range of devices, procedures and medications which assist women to prevent pregnancy.
- Hormonal -> chemicals are added to the body
o Prevent ovulation
o Change cervical mucus to make it impenetrable to sperm
o Slow down/kill sperm
o Reduction of endometrial lining –> fertilized egg cannot implant - Barrier dependent: Physical barrier between semen and vagina/uterus
2
Q
the pill
A
- Oral contraceptive taken daily
- Best taken at the same time to ensure constant hormone levels
- Can contain estrogen, progestin or mix
- Prevents ovulation
- Thin uterine lining
- Progestin thickens cervical mucus
- Estrogen: prevents pituitary form releasing LH – no ovulation
- Side effects include moodiness, headaches, nausea, blood clots (estrogen), heart attack & stroke
- Not effective if diarrhoea or vomiting
3
Q
mechanism of the pill
A
- Combined oral contraceptive pill contains synthetic estrogen & progesterone
- High levels of estrogen and progesterone in blood
o negative feedback to hypothalamus and anterior pituitary
o less production of FSH and LH
o Inhibited follicle maturation in female ovaries
o Progesterone prevents LH surge
o No ovulation - During placebo pills of package estrogen and progesterone in blood will fall
o no negative feedback to hypothalamus and anterior pituitary
o LH and FSH will be produced by anterior pituitary
o follicles will start to mature
o after ~2days progesterone levels low enough for menstruation to occur
4
Q
plasma concentration profile of chemicals taken orally
A
- With oral intake of chemicals at first spike in plasma drug levels
- Drug levels in plasma then decline over time
- Drug becomes ineffective at the suboptimal plasma concentration
o A second tablet has to be taken before plasma levels drop to suboptimal levels - Decrease in plasma drug concentration determines when next tablet has to be taken
- Most drugs coated/in capsules & chemically modified –> get reabsorbed slower but also maintain their effective levels longer
- Companies invest in chemical modifications of drugs to make their administration convenient – e.g. 1 tablet a day (not e.g. 1 every 3.2hours)
Plasma concentration profile of oral contraceptive pill: To prevent suboptimal levels, orally administered drugs best taken at the same time every day
5
Q
the mini pill
A
- Contains only synthetic progesterone and does not contain estrogen = progestin only pill
- Pill is taken continuously without any breaks between packets
- Thickens cervical mucus –> prevents passage of sperm into uterus
- May prevent ovulation
- Thins endometrial lining so no implantation
- Usually no menstruation
- Not effective if diarrhoea or vomiting
6
Q
morning after pill - plan B
A
- Emergency contraception
- Can be taken up to 5 days after unprotected intercourse but effectiveness decreases after 24h
- Same hormones as in birth control pill but higher dosage
- High amount of hormone prevents ovulation
- Will not stop an existing pregnancy
7
Q
vaginal ring combined contraceptive
A
- Clear soft flexible circular ring inserted in vagina around cervix and left for 3 weeks
- Releases progestin and estrogen
- Hormones from ring absorbed through vaginal wall
8
Q
plasma concentration of depot chemicals - time profile
A
- Depot chemicals aim to have therapeutical drug level maintained
- Aim to avoid toxic levels and high concentrations to avoid side effects
- Aim to avoid suboptimal/ineffective concentrations
- Less fluctuation of chemical levels in blood
- Hormone releasing implants etc. have to have high dosages as they are only administered e.g. once every month (infrequently)
- They release chemicals more constantly than orally administered ones
9
Q
combined contraceptive patch
A
- Bandage like hormone patch
- Changed weekly, no patch in 4th week
- Releases progestin and estrogen into blood
- Hormones absorbed through skin
- Can cause skin irritation
- Less effective in obese people
10
Q
contraceptive implants
A
- Soft rod placed under skin in upper arm
- Slow release of hormones into system
- Prevents pregnancy for >3 years but can be removed any time
- Risk that implant moves –> can be ”lost” in muscle
11
Q
3 month shot
A
- Long acting hormone injection
- Given every 3 months in muscle of arm or buttocks
- Not reversible – if rejection occurs hormones cannot be taken out
- Constant levels of progestin from muscle into blood
- Can take a long time to get pregnant after one shot
12
Q
IUD (intrauterine devices)
A
- Inserted into the uterus
A) copper - > 10 years
- Interferes with sperm, fertilization and prevents implantation
- Side effect: heavy or irregular menstruation
B) hormonal
- Plastic T shaped hormone reservoir
- Releases synthetic progestin
- Changes cervical mucus
- Reduced uterine lining
- Stops or slows sperm and oocyte
- > 5 years
- Can be removed at any time
- Side effect: missed periods (amenorrhea)/little menstruation, spotting
13
Q
diaphragm
A
- Soft silicone dome that covers cervix with a flexible rim that holds spermicide
- Once inserted held in place by pelvic muscles
o barrier to prevent sperm from passing through cervix into uterus
o sperm die off quickly in the vagina (spermicide) - Needs to be left in for 6h after intercourse
- Can be used for up to 24 hours
14
Q
cervical cap
A
- Cervical cap is similar to the diaphragm but smaller
- Soft latex or silicone cup holding spermicide
- Designed to fit cover cervix only
- Can be used for up to 42 hours
- Needs to be left in for 6h after intercourse
15
Q
female condom
A
- Soft loose pouch that is inserted in the vagina
- Barrier method – prevents sperm from entering uterus
- Made of nitrile
- Flexible rings at each end hold it in place
- One time use only
- Can be put in 8h before intercourse
