Hormonal and maternal adaptations to pregnancy Flashcards
What changes occur in the maternal red blood cells of a pregnant woman?
Synthesis increases (stimulated by erythropoetin)
Number increases, but apparent anaemia due to dilution
Haematocrit falls from approx 40% to 32%
30% increase in 2,3-DPG facilitates offload of O2 to foetus
What can low folate levels in pregnancy lead to?
Neural tube defects
What role do oestrogens play in pregnancy?
Stimulate synthesis of liver fatty acids and cholesterol
Cardiovascular adaptation to pregnancy
Growth of uterus
Priming of uterus for labour
Weak any-insulin activity (via enhanced cortisol)
Onset of labour-relative risk
Cervical ripening
What is the role of progesterone in pregnancy?
Prepares and maintains the endometrium to allow implantation
Produced initially by corpus luteum (up to day 50-60) then placenta
Suppresses maternal immunologic response to foetal antigens, preventing maternal rejection of trophoblast
Plays a role in parturition
Acts as a substrate in foetal adrenal production of glucocorticoidss and mineralocorticoids
Growth of mammary glands
Maintenance of pregnancy (inhibits uterine contractility, prevents ripening of cervix)
Where is progesterone produced in pregnancy?
Produced initially by corpus luteum (up to day 50-60) then placenta
What are the functions of hCG
Rescue and maintenance of function of corpus luteum (continued progesterone production)
Stimulation of maternal thyroid activity (binds to TSH receptors of thyroid cells)
Maternal lipolysis and increase in maternal free fatty acids, providing a source of energy for maternal metabolism and foetal nutrition
What placental protein is low in preeclampsia?
PlGF, placenta growth factor
What cells secrete leptin?
Cytotrophoblast cells, syncytiotrophoblast cells
How are leptin levels in pregnancy vs. in non-pregnant women
Sig. higher in pregnant women then in non-pregnany women
What is leptin used for in pregnancy?
Stimulates placental amino acid/fatty acid transport
Correlated positively with foetal birthweight
What causes peripheral resistance to fall in pregnancy?
Increased NO synthesis
Increased prostacyclin synthesis
Increased compliance of vessels due to structural changes
Describe how renal function changes during pregnancy
Plasma concentrations of renal function (like urea, creatinine) decrease
Glycosuria
Calciuria
Urinary freq. increases
Urinary stasis due to dilatation of collecting system
Describe how pulmonary function changes during pregnancy
Tidal volume increases Deep breathing stimulated by progesterone Respiratory rate unchanged Expiratory reserve reduced PCO2 falls, PO2 increases
Describe how the gastrointestinal tract changes in pregnancy
Reduced smooth muscle tone (lower motility, mobility, cardiac sphincter tone)
Leads to biliary stasis, gastric reflux, increased nutrient absorption, water reabsorption
