Pregnancy Flashcards
What is the role of progesterone in early pregnancy?
- Suppress milk secretion
- Suppress uterine contractions
- Suppress hypothalamus and pituitary
What is the role of oestrogen in early pregnancy?
- Increase uterine blood flow
2. Increased vessel growth
What occurs to the progesterone:oestrogen ratio in late pregnancy?
Stable progesterone with increasing oestrogen
- Initiates parturition
- Initiates lactation
Give five roles of oestrogen during pregnancy
- Priming agents, including receptors
- Growth of uterus and mammary tissue
- Behavioural effects
- Feedback on hypothalamus
- Increases uterine blood flow
Give five roles of progesterone during pregnancy
- Growth of endometrium and myometrium
- Growth of mammary tissue
- Behavioural effects
- Negative feedback on hypothalamus
- Inhibition of smooth muscle
How does the maternal pituitary gland change during pregnancy?
Increases in size by 30-50%
When is increased pituitary size clinically significant?
- Acromegaly, with an already enlarged pituitary gland, may compress the optic chiasm leading to blindness
- Vascular accident during delivery can lead to Sheehan’s syndrome
What is Sheehan’s syndrome?
- Failure to lactate and resume menstrual cycles
2. Associated with post-partum haemorrhage
What mediates increased calcium uptake?
Increase PTH and 1,25DHCC
What mediates increased levels of adrenal cortical hormones?
Oestrogen-induced increase in binding globulins
What is the average weight gain in pregnancy?
12.5kg
Who tends to gain more weight during pregnancy?
Younger, lighter women
What contributes to weight gain during pregnancy?
60% water
- 3L in fetus
- 1L in placenta, uterus and amniotic cavity
- 3L in maternal tissue fluid
- 25L extra plasma
> 3kg fat deposition
How does blood volume change in pregnancy?
40% increase in plasma volume due to upregulation of renin-angiotensin system
Haemodilution as red cell mass increases less than plasma increase
What causes increased red blood cell mass?
Increased erythropoiesis
How does clotting change?
- Platelet count falls
2. Clotting factors increase
How does blood flow change?
Increased cardiac output and heart rate
Decreased resistance
Increased flow to kidneys and skin
What is transient high blood pressure?
Mild rise in BP during pregnancy or soon after delivery
Not accompanied by oedema or proteinuria
Begins after midpoint of pregnancy
What is pre-eclampsia?
Commonest cause of hypertension during pregnancy
ABP of at least 140mmHg/90mmHg
Oedema and proteinuria
Who is most at risk of pre-eclampsia?
- First time mothers
- Younger than 17 or older than 35
- Family history of pre-eclampsia
What are the three causes of respiratory changes?
- Space occupying lesion in abdomen puts upwards pressure on diaphragm
- Increased oxygen consumption
- Circulating hormone levels
When is breathlessness during pregnancy relieved?
- Pelvic ligament softening at 36 weeks
2. Fetal head descends into pelvis and engages, relieving pressure