Physiology and pregnancy Flashcards
What hormone drives maternal adaptations?
Progesterone
proactive changes rather then reactive, changes occur before necessarily needed
Give 3 reasons for adaptations observed in pregnancy:
- Suitable environment for foetal nutrition, growth and development
- Protect and prepare mother
What type of immunity is transfered to the foetus?
Passive immunity
What causes 40% of premature deliveries and why?
Maternal infections because mother has a suppressed immune state. Infections and parasitic diseases are more dangerous in pregnancy
What effect does pregnancy have on the mothers organs?
- Thymus: shrink
- Spleen: enlargement due to ^ erythrocytes and immunoglobulin producing cells
- Para-aortic lymph nodes: enlargement as uterus drains here
Give 2 changes pregnancy causes to the uterus:
- Myometrium growth due to muscle hypertrophy and elongation of cells
- Vessel hypertrophy and ^ flow, trophoblast invasion of spiral arterioles (up to 24 weeks)
What prevents uterine contractility/ when do contractions start in pregnancy?
Progesterone prevents contractions.
Low level contractions start at week 7 (only contraction during labour cause cervical dilation)
What changes are undergone by the cervix during pregnancy?
- Concentration of collagen reduces in third trimester
- Increased vascularity
- Antibacterial plaque of mucus forms
How much does CO increase by in the first trimester? By what degree does the heart rate increase by during pregnancy?
40%
15bpm
Why is heart disease a concern during pregnancy?
Due to higher CO during pregnancy, it could precipitate HF in those with underlying heart disease.
What allows the expansion of the mothers blood volume during pregnancy?
Reduction of total peripheral resistance by 1/2.
Caused by activation of RAS which ^ vasodilators
What effect does pregnancy have of BP?
Reduces mean arterial pressure (MAP) by about 10mmHg.
What happens with the 4th and 5th Korotkoff sounds during pregnancy?
Gap widens
What causes supine hypotension syndrome?
Compression of IVC in late pregnancy - decreased venous return
What should be done to ensure consistent accurate BP readings?
Measure BP in same posture each time
What effects does pregnancy have of RBC?
What happens to WBC numbers during labour and delivery?
Red cell mass ^ 20-30%
Haematocrit falls
Neurophil count ^^
What happens to a mothers lipid levels during pregnancy?
Hyperlidaemic state (but not atherogenic) - free fatty acids are raised
How does the volume of air inhaled and exhaled by a mother change during in pregnancy?
What happens to a mothers PaCO2 during pregnancy?
Volume ^ 40%.
PaCO2 falls (results in better gas exchange from foetus)
What happens to renal function and renal markers during pregnancy?
GFR ^
Plasma concentration of urea and CK fall
What is typical to observe on urine dip during pregnancy?
Glycosuria
Mild proteinuria
How does maternal weight change during pregnancy?
Total weight gain ~12.5kg (27.5 pounds)
- 0.3kg/week up to 18weeks
- 0.5kg/week up to 28 weeks
- 0.4kg/week til term
What would too little or too much weight gain cause concern of?
Too much - investigate fluid retention
Too little - IUGR
List 4 breast changes noted in pregnancy:
- Tenderness
- increased size
- Nipple enlargement (progesterone + prolactin)
- Ductal proliferation (oestrogen, GH and glucocorticoids)
What hormone stimulates the production of cortisol?
ACTH
What are the levels of ACTH like during pregnancy?
High - so that more cortisol is produced
What does leucine aminopeptidase lower during pregnancy?
Oxytocin
What part of the pituitary releases prolactin?
Anterior pituitary
What does the posterior pituitary produce?
Oxytocin
ADH (antidiuretic hormone)
Why do some mothers experience constipation?
Due to increased water uptake from LI.
Enhanced nutrient uptake in SI is also experienced.
Where do placental villi form from?
Langhans cells
When does implantation of the blastocyst occur?
Day 7