Oral Contraceptives

Question 1

From what tissues is oestradiol released?

Answer 1

Ovary
Placenta
Small amount from testes and adrenal cortex

Question 2

From what tissues is progesterone released?

Answer 2

Ovary
Placenta
Small amount from testes and adrenal cortex

Question 3

From what tissues is testosterone released?

Answer 3

Testes

Small amount from ovaries and adrenal cortex

Question 4

What is the problem with using natural oestrogens as part of an oral contraceptive?

Answer 4

Broken down quickly by hepatic first pass metabolism

Question 5

Why can’t natural progesterone be used as part of the oral contraceptives?

Answer 5

Not orally effective/available

Question 6

What is the feedback effect of oestrogen on the HPG axis?

Answer 6

Effectively inhibits FSH release

May inhibit or stimulate LH release depending on concentration

Question 7

What is the feedback effect of progesterone on the HPG axis?

Answer 7

Inhibits GnRH release
Does not have much of an effect on FSH release
High doses will inhibit LH

Question 8

Give an example of a synthetic oestrogen

Answer 8

Ethinyloestradiol (most commonly used)

Question 9

Give an example of a 1st generation synthetic progestogen

Answer 9

Levonorgestrel (commonly used in OCs as well as HRT and the morning after pill)

Question 10

What are the disadvantages of the 1st generation progestogens?

Answer 10

Androgenic (can cause hirsutism)

Question 11

What are the disadvantages of the 2nd generation progestogens?

Answer 11

Expensive

Increased incidence of thromboembolic events

Question 12

What conditions are 3rd generation progestogens (cyproterone, drospirenone) used to treat?

Answer 12

Dysmenorrhea/menorrhagia (prevents IDA)

PCOS

Question 13

What is the disadvantage of cyproterone?

Answer 13

Highest risk of thromboembolic events

Question 14

What is drospirenone?

Answer 14

A 3rd generation progestogen/analog of spironolactone that acts as an antiandrogenic diuretic

Question 15

What are the 2 main effects of drospirenone?

Answer 15

Antimineralocorticoid

Antiandrogenic

Question 16

What drugs are used to treat PCOS?

Answer 16

OCs with 3rd gen progestogens
Spironolactone
Metformin

Question 17

What are some of the possible serious complications of untreated PCOS?

Answer 17

Insulin resistance
CVD
Endometrial cancer

Question 18

What are the 3 different forms of OCs available, in order from most to least effective?

Answer 18

Combined preparations
Sequential preparations
Progestogen-only oral preparations (mini-pill)

Question 19

What is the difference between combined and sequential preparations of OCs?

Answer 19

Combined: mixture of oestrogen and progestogen in a fixed ratio of doses
Sequential: ratio of doses varies to correspond approximately to changes in endogenous oestrogen and progestogen

Question 20

Why can the mini-pill be used by lactating women?

Answer 20

Progestogen at this dose does not inhibit PLN release, where the addition of oestrogen would

Question 21

What kind of progestogens are generally included in the mini-pill?

Answer 21

Usually 1st gen

Question 22

What is the problem with low dose oestrogen OCs?

Answer 22

May get breakthrough bleeding (but less other adverse effects)

Question 23

For which OCs is it essential to take the pill at the same time every day?

Answer 23

Sequential preparations

Progestogen-only oral preparations

Question 24

List 15 possible adverse effects of COCs

Answer 24

Hypertension
VTE
Cancer (some evidence for breast, cervical and uterine)
Nausea/vomiting
Dizziness
Flushing
Breast discomfort
Headache (especially in women who get headaches normally before onset of menses)
Weight gain
Decreased libido
Chloasma
Acne
Depression
Irritability
Fatigue

Question 25

Is the risk of developing or exacerbating existing hypertension with COC use reversible or irreversible?

Answer 25

Reversible

Question 26

What is the risk of VTE with COC use dependent on?

Answer 26

Dose of oestrogen (main factor; higher dose confers higher risk) Type of progestogen Presence of other risk factors

Question 27

When is risk of VTE highest with COC use?

Answer 27

In the 1st year of use

Question 28

What is the risk of VTE with use of COCs containing cyproterone?

Answer 28

60/100,000 patient-years (risk in pregnancy is 60/100,000 pregnancies)

Question 29

Describe the increase in risk of cervical cancer with COC use and how this can be managed

Answer 29

Risk is slight but increases with duration of COC use | Women should be regularly screened for cervical cancer

Question 30

Describe the influence of COCs on uterine cancer risk

Answer 30

The increased incidence of uterine cancer caused by OCs is diminished when progestogen is given concurrently to women with an intact uterus (overall effect is protective)

Question 31

What is the proposed mechanism of weight gain with OC use?

Answer 31

Due to water retention (oestrogen can act similarly to aldosterone) and possibly anabolic effects

Question 32

List 6 benefits of COC use

Answer 32

Decreased risk of endometrial cancer Decreased incidence of ovarian cancer and ovarian cyst formation Decreased risk of colorectal cancer Protective effect on benign breast tumours Decreased risk of bone fractures Decreased dysmenorrhoea and menorrhagia (and therefore protection against IDA)

Question 33

What is the mechanism of action of the vaginal ring? What is its advantage over OCs?

Answer 33

Vaginal ring with ethinyloestradiol and etonogestrel is inserted into the vagina, left for 3 weeks and removed for 1 week; the process is repeated Effective with lower doses of hormones as it bypasses the portal circulation

Question 34

List 3 non-oral forms of progestogen-only contraceptives, their method of administration and the duration of effectiveness

Answer 34

Medroxyprogesterone: IM, every 12 weeks Etonorgestrel: subdermal implant, up to 3 years Levonorgestrel: IUDs, up to 5 years

Question 35

What is emergency contraception? How does it work? How effective is it and over what timespan?

Answer 35

1 tablet of 1500ug of levonorgestrel (10x that of OCP dose) May inhibit LH to prevent ovulation, changes the uterine tubing and lining to prevent implantation ~85% effective within 72 hours of unprotected intercourse

Question 36

What other form of emergency contraception besides the morning-after pill is available? How effective is this?

Answer 36

Copper IUD | 99% effective but must be inserted by a doctor (morning-after pill can be obtained without prescription)

Question 37

What is the role of progestogens as contraceptive agents?

Answer 37

May inhibit LH release to prevent ovulation if high enough dose is delivered Continuous exogenous progestogen administration makes the endometrium unfavourable for implantation and the vaginal/cervical mucus more inhospitable May also interfere with coordinated contractions of the cervix, uterus and uterine tubes which ordinarily aid fertilisation and implantation