oestrogens, progesteron and oral contraceptives

Question 1

17β-Estradiol is synthesised by…?

Answer 1

maturing follicle in 1st half of cycle

Question 2

How can Estradiol activate ER-responsive gene expression?

Answer 2

ligation and dimerisation of oestrogen receptors in the nucleus

Question 3

Progesterone is secreted by…?

Answer 3

the corpus luteum in 2nd half of cycle

Question 4

What occurs when there is an activation of progesterone?

Answer 4

receptors, dimerisation and nuclear translocation drives progesterone-responsive gene expression

Question 5

What are the actions of estradiol during the menstrual cycle?

Answer 5

modulates FSH and LH release
stimulates endometrial proliferation and growth; breast growth
increases expression of progesterone receptors
stimulates copious watery secretions from cervix

Question 6

What are the actions of progesterone in the menstrual cycle?

Answer 6

modulates FSH and LH release
stimulates cyclical growth of uterus and breasts
reduces uterine excitability
produces secretion of less abundant, thicker mucus from cervix
reduces effect of E2 in endometrium

Question 7

Oestrogen and progesterone stimulate…?

Answer 7

growth of the endometrium in preparation for implantation

Question 8

Progesterone after non-conception induces…

Answer 8

changes in cervical mucous that prevents sperm motility; levels decline as corpus luteum regresses

Question 9

During conception and implantation progesterone levels…

Answer 9

elevate and are maintained by the developing placenta and pituitary; FSH/LH suppression continues

Question 10

What is required for embryo survival and immune rejection?

Answer 10

Progesterone

Question 11

Why does progesterone need to be maintained?

Answer 11

to maintain embryo viability and uterine quiescence

Question 12

What is the use of oral contraceptives?

Answer 12

mimics the endocrine environment of pregnancy, shutting down the ovulatory cycle and preventing ovulation and fertilisation and implantation

Question 13

What are the two major groups of Oral Contraceptives?

Answer 13

1. Combined oral contraceptives

2. Progestogen-only contraceptives

Question 14

What is a combined oral contraceptive?

Answer 14

the combination of a synthetic oestrogen and a synthetic progestogen

Question 15

What are two synthetic oestrogens used in combined OCs?

Answer 15

ethinyloestradiol

mestranol

Question 16

What are some synthetic progestogen used in OCs?

Answer 16

1st gen - ethisterone
2nd gen - lveonorgestrel
3rd gen - desogestrel

Question 17

What are the mechanisms of combined OCs?

Answer 17

1. inhibit ovulation
2. thicken cervical mucus
3. reduce receptivity of endometrium

Question 18

What is the timeline for combined OCs?

Answer 18

21 days OC + 7 day pill break
21 days OCs + 7 days placebo

= induces withdrawal bleeding

Question 19

What are the benefits of using combined OCs?

Answer 19

highly effective, reversible + safe contraception
decrease risk of ovarian and endometrial cancer
reduced risk of benign breast disease
improvement in acne

Question 20

What are some common adverse effects of using combined OCs?

Answer 20

breakthrough bleeding (increase oestrogen or progestogen)
nausea, vomiting (decrease oestrogen)
fluid retention, breast tenderness (decrease oestrogen)
melasma (avoid sun + stop oestrogen)

acne/weight gain
depression, fatigue
decreased libido

Question 21

What are some potential serious adverse effects of combined OCs?

Answer 21

1. oestrogen can cause enhanced coagulation and COCs may be associated with increased risk of myocardial infarcation + venous thromboembolism
2. increase 20% risk in breast cancer

Question 22

What are some contraindications for combined OCs?

Answer 22

pregnancy 
thromboembolic disorders
oestrogen-dependent tumours
focal migraine
major elective surgery
breastfeeding

Question 23

Who are suitable for progestogen-only oral contraceptives?

Answer 23

breastfeeding women
focal migraine
are over 35 and smoke, or other cardiovascular risk factors
before major surgery

Question 24

What are the mechanisms of progestogen-only OCs?

Answer 24

for cervical mucus thickening and decrease in amount

Question 25

How do COCs reduce the likelihood of pregnancy by inhibiting…?

Answer 25

1. ovulation
2. fertilisation
3. implantation