REPRODUCTIVE ENDOCRINOLOGY Flashcards
Define contraception
prevention of
pregnancy before foetal implantation.
discuss characteristics of Period (menstruation)
- starts from the age of 12 (range 8-15)
- The period usually lasts 4-8 days
- The blood lost is approximately 5-12 tablespoons (up to180 ml)
- The mensural cycle is counted from the 1st day of menstruation
- The cycle lasts for 28 days (range 23-35)
- Continues until menopause (approx. age 52)
what occurs during the follicular phase of the menstrual cycle
when follicles in the ovaries mature and end in ovulation
what occurs during the luteal phase of the menstrual cycle
thickening of endometrial lining to facilitate implantation
what is the HPG-axis
Hormonal regulation –
the Hypothalamic-pituitary-gonadal (HPG) axis
explain the events in HPG-axis in the Follicular phase
in the Hypothalamus Gonadotropin-releasing hormone (GnRH)is Released in a pulsating manner (Follicular phase: Faster pulses)which stimulates the Anterior pituitary gland to release Follicle-stimulating hormone (FSH) and Luteinising hormone (LH) causing grow multiple eggs grow at the same time primary egg matures the fastest and released inhibin and oestrogen from the Ovaries is released Oestradiol (oestrogen) After 2 days over a high threshold → LH surge(ovulation)
what does FSH do
causes the follicles to grow multiple eggs grow at the same time primary egg matures the fastest
what does LH do
causes the LH surge which is needed for egg to be released
is oestrogen only inhibitory
oestrogen can be both inhibitory and non inhibitory depending on the levels
discuss signs of ovulation
Higher progesterone levels after ovulation
causes body temperature to increase
* High oestrogen level causes cervical mucous
to change texture to be like “egg white”
* Clearer and stringy instead of thick
* Sperm can pass the mucous easier
explain the events in the HPG-axis – Luteal phase
- Upon ovulation Corpus luteum (aka “Yellow body”), a small cyst inside the ovary, will form and produce high levels of Progesterone, and moderate levels of oestradiol.
- Corpus luteum does also produce inhibin.
- The lower moderate level of oestradiol will inhibit GnRH release
- Progesterone will prepare the endometrium for implantation of a fertilised egg
discuss the menses Phases of the uterine cycle
Day one, the first day of the mensuration/period
* Occurs if fertilisation did not take place
* Degeneration and shedding of the endometrium
* Often accompanied by cramps caused by
prostaglandins
discuss the proliferative Phases of the uterine cycle
Secretion of oestrogen from the maturing follicles lead to the proliferation of cells in the endometrium → endometrium thickens
discuss the secretory uterine cycle
Stimulation of changes to the endometrium by progesterone making it receptive to
implantation of the blastocyst
* Increased blood flow
* Increased uterine secretion
* Decreased contractility in the uterine wall
discuss Hormone levels in pregnancy
- When the fertilised egg successfully starts implants in uterus wall trophoblast tissue (to
become placenta) releases hCG - Measurement of hCG in urine is the main method to confirm pregnancy
- Oestrogen and progesterone will gradually increase together
discuss the effectiveness of hormonal contraceptive
what is the Combined Oral Contraceptives
Pills that contain oestrogens & progesterone (Progestogens) and Maintain sustained levels of hormones
through the cycle
what condition does the Combined Oral Contraceptives mimic
pregnancy
discuss oestrogen the mechanism of action of the Combined Oral Contraceptives
Oestrogen cause the inhibition of
hypothalamus and the Anterior
Pituitary Gland causes
→ Inhibits LH and FSH secretion
→ No follicle growth
→ No ovulation
→ No corpus luteum formation
discuss progesterone mechanism of action in the Combined Oral Contraceptives
- Progesterone also inhibits the
Anterior Pituitary Gland
→ Thickening of cervical mucous
(harder for sperm to pass
through)
→ Endometrial change
discuss the efficacy of Combined Oral Contraceptives
High chance to work well if taken as intended
* 99% efficiency to prevent pregnancy
* Failure is usually caused by missed doses, drug
interactions (some antibiotics), diarrhoea & vomiting
discuss the Side effects associated with Combined Oral Contraceptives
- Increased risk of CVD (cardio vascular disease (thrombosis) due to oestrogen)
- Breast cancer
- Minor effects include nausea, weight gain, depression
discuss the health benefits associated with Combined Oral Contraceptives
- Decreased risk of ovarian and endometrial cancer
- Decreased incidence of pelvic inflammatory
disease and ovarian cysts.
what are Progesterone Only Contraceptives
Progesterone Only Contraceptives are made of
synthetic progesterone
* Mini pill – taken every day without breaks
what are the other forms of what are Progesterone Only Contraceptives
Depo-injections and contraceptive implants
* Depo-injections last 8-13 weeks
* Contraceptive implants last 3 years
* Slow release, higher dose
discuss the mechanism of action of the mini pill as a form of Progesterone Only Contraceptives
Low dose progesterone inhibits the
Anterior Pituitary Gland
→ Anterior Pituitary Gland still
responds to GnRH
→ Inhibits LH and FSH secretion
→ Ovulation can still happen
depending on the HPGsuppression
→ Thickening of cervical mucous
(harder for sperm to pass through)
→ Endometrial changes
discuss the mechanism of action of implants and injections as a form of Progesterone Only Contraceptives
Mechanism of action – high dose
* High dose progesterone inhibits the
Anterior Pituitary Gland and the
hypothalamus
→ Inhibits LH and FSH secretion
→ No follicle growth
→ No ovulation
→ No corpus luteum formation
→ Thickening of cervical mucous
(harder for sperm to pass through)
→ Endometrial changes
discuss the efficacy of Progesterone Only Contraceptives
High chance to work well if taken as intended
* 99% efficiency to prevent pregnancy
* Failure is usually caused by missed doses, drug
interactions (some antibiotics), diarrhoea & vomiting
* Needs to be taken at a similar time every day! Higher risk to fail if not being consistent