S6) Maternal Physiological Adaptations in Pregnancy Flashcards
Identify the 3 types of changes in maternal physiological adaptation to pregnancy
- Biochemical changes
- Physiological changes
- Structural changes
Why do maternal physiological adaptations to pregnancy occur?
- Provide a suitable environment for the nutrition, growth and development of the foetus
- Prepare the mother for birth
- Prepare the mother for support of the new born
Identify the 6 hormones which orchestrate maternal physiological adaptations to pregnancy
- hCG
- Progesterone
- Oestrogen
- Relaxin
- hPL
- Inhibin
hCG is released from the synctiotrophoblast.
What role does it have in early pregnancy?
hCG mimics the action of LH and maintains the corpus luteum so it can produce oestrogen and progesterone until the placenta can take over
hCG reduces the maternal levels of IgA, IgG and IgM.
Why is this beneficial to the foetal-placental unit?
The maternal antibodies do not attack the foetus as a foreign antigen
hCG reduces the maternal levels of IgA, IgG and IgM.
What consequence does this have on the mother?
The mother becomes slightly immunodeficient and is at increased risk of developing infections
Progesterone relaxes smooth muscle.
Identify 4 effects of increasing progesterone levels on the GI tract function which the mother may complain of?
- Vomiting
- Constipation
- Heartburn
- Indigestion
Which oestrogen level in the maternal serum/urine best indicates foetal progress and why?
Oestriol (E3) as it shows the development of the liver and has its own singular pathway
Identify 3 hormones which stimulate breast growth
- Oestrogen
- Progesterone
- Prolactin
How does inhibin (from the corpus luteum and placenta) prevent further pregnancies from occuring in the pregnant state?
Inhibin prevents follicular development by inhibiting FSH
Glucose and amino acid metabolism are altered in pregnancy to favour the nutritional supply to the foetus.
Identify 4 of these changes
- Reduction in maternal [blood glucose] and [amino acid]
- Diminished maternal response to insulin in second ½ of pregnancy
- Increased maternal free fatty acid, ketone and triglyceride levels
- Increased insulin release in response to a normal meal
Identify the 4 hormones which orchestrate the changes in glucose and amino acid metabolism in pregnancy
- Prolactin
- Oestrogen
- Progesterone
- hPL
What effect does progesterone have on glucose metabolism?
Progesterone stimulates appetite in the first half of pregnancy and diverts glucose into fat synthesis
What effect does oestrogen have on glucose metabolism?
Oestrogen stimulates an increase in prolactin release
Identify the 3 main hormones responsible for maternal resistance to insulin
- Prolactin
- hPL
- Cortisol
Describe the significance of maternal decline in glucose usage
- Gluconeogenesis increases, maximising the availability of glucose to the foetus
- Maternal energy demands are met by fatty acid metabolism (later in pregnancy)
What is the benefit of increased maternal deposition of fat by progesterone?
Prepares for higher energy demands from the foetus later in pregnancy
Which hormone is primarily responsible for changes in maternal carbohydrate metabolism during pregnancy?
Human placental lactogen (hPL)
As pregnancy progresses, the foetal-placental unit’s increasing nutritional needs aren’t met via maternal vascular-neogenesis.
Describe 2 changes which accomodate this
Changes in the function of maternal baroreceptors and volume receptors:
- Increased blood flow to the growing breasts, kidneys and Gi tract
- Plasma volume increases while peripheral vascular resistance falls
Identify 2 changes to the maternal heart which can be observed on examination
- Hypertrophy (eccentric)
- Upward displacement of flow murmurs