Physiology of Pregnancy and Lactation Flashcards
The placenta is derived from which tissues?
Trophoblast and decidual
Placental villi are formed from what?
The embryo sending capillaries into the syncytiotrophoblast projections
What provides early nutrition for the embryo?
Invasion of trophoblastic cells into the decidua
The villi extended into the uterine wall contain what?
Blood vessels from the embryo
How does circulation within the intervillous space act?
Arteriovenous shunt
Which structure plays the role of the foetal lungs?
Placenta
Oxygen diffuses from the foetal/maternal circulation into the foetal/maternal circulation
From the maternal into the foetal circulation
Oxygen saturated blood returns to the foetus via which structure?
Umbilical vein
Which three factors facilitate the supply of the foetus with oxygen?
Foetal Hb
Higher Hb concentration in foetal blood
Bohr effect
How does water diffuse into the placenta?
Along its osmotic gradient
How does glucose enter the placenta?
Simplified transport
What is the effect of human chorionic gonadotropin?
Prevents involution of the corpus luteum
Give some effects of human chorionic somatomammotropin
Protein tissue formation
Increased foetal glucose
Breast development
Give some effects of increased progesterone levels during pregnancy
Development of decidual cells
Decreased uterus contractility
Prepares for lactation
Give some effects of increased oestrogens during pregnancy
Enlargement of uterus
Breast development
Relaxation of ligaments
Which oestrogen provides an indicator for foetal vitality?
Oestriol
CRH released from the placenta can cause maternal hypertension and insulin resistance. How?
As it increases ACTH levels increasing aldosterone and cortisol
What effect can placental HCG have on the mother?
Hyperthyroidism
Increased calcium demands from the placenta can lead to which condition?
Hyperparathyroidism
Give some of the cardiovascular changes that occur during pregnancy
Increase in cardiac output
Heart rate increases
Blood pressure falls (during second trimester)
Why does cardiac output increase during pregnancy?
Due to demands of uteroplacental circulation
Why does cardiac output decrease during the last 8 weeks of pregnancy?
As the uterus compresses the inferior vena cava
Give some haematological changes that occur during pregnancy
Plasma volume increases
Erythropoesis (RBC) increases
Hb decreases
What causes lung function to change during pregnancy?
Progesterone increases
Enlarging uterus
What respiratory changes occur during pregnancy?
Lower CO2 levels
O2 consumption increases
What changes take place in the renal system during pregnancy?
GFR increases
Increased re-absorption ions and water
Increased urine formation
What is the definition of pre-eclampsia?
Pregnancy induced hypertension + proteinuria
Give some risk factors for pre-eclampsia
Hypertension Diabetes Autoimmune disease Renal disease FHx PMHx
What occurs in eclampsia?
Vascular spasms
Extreme hypertension
Chronic seizures
Coma
How is eclampsia treated?
Vasodilators and C-section
What is the average maternal weight gain in pregnancy?
6kg
How many extra calories does the mother need per day during pregnancy?
300
When does the mother’s anabolic phase occur?
Weeks 1-20
What occurs in the mother’s anabolic phase?
Normal/increased sensitivity to insulin
Lower plasmatic glucose level
Lipogenesis
Growth of breasts/uterus
What occurs in the mother’s catabolic phase?
Maternal insulin resistance
Increased nutrient transport to placenta
Lipolysis
Give some common nutritional needs in pregnancy
Folate
Vit D supplements
High protein supplements
Iron
During parturition, the oestrogen:progesterone ratio increases/decreases
Increases - oestrogen increases contractions
Which pituitary hormone increases contractions?
Oxytocin
The stretch of which structure increases contractility
Cervix
Which hormone induces oxytocin receptors on the uterus?
Oestrogen
Outline the positive feedback role of oxytocin in labour
Oxytocin stimulates placenta to make prostaglandins which stimulates more vigorous contractions of the uterus which increases oxytocin production
What are the three stages of labour?
Cervical dilation
Passage through birth canal
Placental expulsion
Which hormone is important in the growth of the ductile system?
Oestrogen
Which hormone is important in development of the lobule-alveolar system?
Progesterone
Which hormone stimulates milk production?
Prolactin
Which hormone helps in milk secretion?
Oxytocin
