Maternal Changes in Pregnancy Flashcards
What are the causative factors of maternal changes during pregnancy?
High levels of steroids (oestrogen & progesterone)
Mechanical displacement
Fetal requirements
What are the repercussions on different systems after pregnancy?
Pregnancy is a physiological event. Systems (usually) return to normal after delivery, but not all
How would we identify an abnormal pregnancy?
To diagnose abnormality in pregnancy need to detect changes in the changes
Why may pregnancy make it difficult to identify disorders?
Pregnancy may:
- exacerbate a pre-existing condition
- uncover ‘hidden’ or mild condition
What main events do pregnancy changes occur to cope with?
Changes designed to cope with several main events:
- increase in size of the uterus
- increased metabolic requirements of uterus
- structural and metabolic requirements of fetus
- removal of fetal waste products
- provision of amniotic fluid
- preparation for delivery and puerperium
What systems undergo maternal changes during pregnancy?
energy balance respiratory system cardiovascular system gastrointestinal system urinary system endocrine system
What placental peptides cause maternal changes?
placental peptides
hCG, hPL, GH
What is the role of maternal steroids?
placenta takes over ovarian (CL) production around wk 7
Name the maternal and foetal steroids
progesterone, oestradiol, oestriol
What are the maternal and fetal pituitary hormones?
GH, thyroid hormones, prolactin, CRF
What systems do the placental steroids affect?
- renin/angiotensin system
- respiratory centre
- GI tract
- blood vessels
- uterine myometrial contractility
How does weight change across pregnancy?
> total gain in weight 12.5-13kg Fetus plus placenta 5 kg Fat and protein 4.5 kg Body Water (this is excluding that in other listed structures) 1.5 kg intravascular, interstitial, intracellular Breasts 1 kg Uterus 0.5- 1kg Ideally keep to less than 13kg: failure to gain or sudden change needs monitoring
How is an energy balance maintained during pregnancy?
Energy output and storage is increased
Why is energy output increased?
to cope with increased respiration and cardiac output
Why is energy storage increased?
for fetus
for labour and puerperium
Why does fat and protein stores increase by 4-5 kg?
increased consumption and reduced use
mainly laid down in anterior abdominal wall
utilised later in pregnancy and puerperium
How much does the metabolic rate rise by during gestation?
350 kcal/day mid gestation 75% fetus and uterus
250 kcal/day late gestation 25% respiration(H&L)
What is the significance of glucose during pregnancy?
- need increased availability in 2nd trimester
- active transport across placenta as fetal energy source
- fetus stores some in liver
Descrube the maternal reserves of glucose in the 1st trimester
1st Trimester Maternal reserves pancreatic β cells increase in number plasma insulin increases fasting serum glucose decreases (laid down as stores and used by muscle)
Describe he fetal glucose reserves in the 2nd trimester
2nd Trimester Fetal reserves hPL causes insulin resistance ie less glucose into stores = increased availability in serum glucose (more crosses placenta) but can cause diabetes
How is the RAAS system affected during pregnancy?
Total water gain
E₂ and particularly P act on renin angiotensin system
Retain fluid better and thirst increases. Plasma levels increase - common for oedema to occur
Albumin levels drop decreasing oncotic pressure
How is respiration affected during gestation?
Oxygen consumption is increased
Bigger deeper breaths taken more frequently causing a 40% increase in minute volume → larger Oxygen pressures in arteries removal of more CO2
Facilitates gas transfer for baby
What is haemodilation?
The apparent anaemia as concentration of Hb falls
How does maternal blood adapt for gestation?
increased efficiency of iron absorption from gut
Also changes in white cells (up) and clotting factors..blood becomes hypercoagulable = increased fibrinogen for placental separation, but increased risk of thrombosis
