Hormones Involved in Parturition Flashcards
When and where is cortisol produced/ secreted?
- Towards end of term pregnancy
- Production stimulated by oestrogen
- Anterior pituitary gland of foetus
Describe the action and effects of cortisol
- Reduces maternal production of progesterone
- Levels increase in response to stress, caused by increased cardiac output and decreased glucose levels (eg)
- Has a positive effect on conditions such as rheumatoid arthritis and eczema
When and where is progesterone produced/ secreted?
- Throughout pregnancy
- Stop prior to onset of labour
- Levels gradually increase at first but then more markedly after week 10
- Placenta
Describe the action and effects of progesterone
- In pregnancy, relaxes smooth muscle, increases body temp, RR and Na and Cl excretion
- Inhibits contractions
- Used for foetal synthesis of testosterone, corticosteroids and mineralcorticoids
- Miscarriages associated with decreased progesterone levels caused by stress
When and where is oestrogen produced/secreted?
- Throughout pregnancy
- Slight rise towards end
- Levels don’t increase until week 9
- Ovaries and placenta
Describe the action and effects of oestrogen
- Promotes growth of endometrium and breasts
- Increases prolactin secretion
- Enhances myometrial activity
- Stimulates fluid retention
- Slight rise can make uterus more sensitive to oxytocin
- Primary oestrogen in pregnancy = oestriol
- Levels increase 100x in pregnancy
When and where are prostaglandins produced/ secreted?
- Late pregnancy
- Production can be stimulated by coitus, VE, membrane sweep, amniotomy and labour
- Not clear where produced but found in foetal membranes, decidua, myometrium and cervix
Describe the action and effects of prostaglandins
Important for the progress of labour
When and where is oxytocin produced/ secreted?
- During labour
- Maternal posterior pituitary gland and foetal pituitary gland in labour
Describe the action and effect of oxytocin
Necessary for effective progress of labour and stimulating the uterus to contract
When and where is relaxin produced/ secreted?
- Throughout pregnancy
- Levels highest in 1st trimester
- Corpus luteum, myometrium and placenta
Describe the action and effect of relaxin
- Acts with progesterone to inhibit myometrial contractility (maintains uterine quiescence)
- Softens pelvic ligaments
- Promotes cervical ripening just before onset of labour
- Associated with endometrial differentiation during embryo implantation and wound healing
When and where is hCG produced/ secreted?
- Early pregnancy
- Max. production = 8-10 weeks
- Trophoblast cells
Describe the action and effect of hCG
- Maintains production of steroid hormones from corpus luteum until placenta takes over
- Acts on LH receptors to prolong life of corpus luteum
- Indicates pregnancy (measureable levels 2 weeks after conception)
- Persistently low levels associated with abnormal placental development/ ectopic pregnancy
- May be responsible for nausea and vomiting
When and where is hPL produced/ secreted?
- Late pregnancy
- Syncytiotrophoblast cells
