Maternal Changes in Pregnancy Flashcards
1
Q
What are the causative factors in the changes in pregnancy?
A
- High levels of steroids
- Mechanical displacement
- Fetal requirements
2
Q
What can pregnancies sometimes do?
A
- Exacerbate a pre-exisiting condition e.g congential heart disease, asthma
- Uncover ‘hidden’ or mild conditon e.g diabetes
3
Q
What are the changes in pregnancy which are designed to cope with several main events?
A
- Increase in size of the uterus
- Hence increased metabolic requirements of uterus to supply the expanding organ
- Structural and metabolic requirements of foetus
- Removal of foetal waste products
- Provision of amniotic fluid
- Preparation for delivery and puerperium (post-natal period)
4
Q
In what systems do changes occur?
A
- Energy balance
- Respiratory system
- Cardiovascular system
- Gastrointestinal system
- Urinary system
- Endocrine system
5
Q
Which hormones cause most of the changes in the maternal body?
A
-
Placental peptides
- hCG (keeps the CL alive), hPL, GH
-
Maternal steroids
- placenta takes over ovarian (CL) production around wk 7
-
Placental and foetal steroids
- progesterone, oestradiol, oestriol
-
Maternal and foetal pituitary hormones
- GH, thyroid hormones (to keep up with the metabolic demands), prolactin, CRF (corticotrophin releasing factor)
6
Q
What are placental peptides?
A
- hCG (keeps CL alive - until 7 weeks - secretes the hormone progesterone)
- hPL
- GH
7
Q
When does the placenta take over ovarian production?
A
At week 7 - when the corpus luteum dies
8
Q
What are the placental and fetal steroids?
A
- Progesterone
- Oestradiol
- Oestriol
9
Q
What are the maternal and fetal pituitary hormones?
A
- GH
- Thyroid Hormones
- Prolaction
- CRF (corticotrophin releasing factor)
10
Q
What do placental steroids affect?
A
- RAAS system
- Respiratory system
- GI tract
- Blood vessels
- Uterine myometrial contractillity
11
Q
How does your weight change when you are pregnant?
A
Total weight gain = 12.5 - 13kg
Ideally keep less than 13kg - failure to gain or sudden change requires monitoring
12
Q
Why do we need to increase energy output?
A
To cope with increased respiration and cardiac output
13
Q
Why does energy storage need to be increased?
A
- For foetus
- For labour and puerperium
14
Q
Why is there a gain in fat and protein stores (4-5kg)?
A
- increased consumption and reduced use
- mainly laid down in anterior abdominal wall
- utilised later in pregnancy and puerperium
15
Q
How does the basal metabolic rate change during pregnancy?
A
- Rises by 350kcal a day mid gestation (75% foetus and uterus)
- Rises by 250kcal a day late gestation (25% respiratory)
16
Q
How does the need for glucose increase in the 2nd trimester?
A
- Increased availabillity in 2nd trimester
- Glucose is transferred across the placenta as foetal energy source via facillitated diffusion
- Foetus will store some glucose in liver
- hPL will cause insulin resistance in mother
- Increased availabillity in serum
- More glucose crosses the placenta
- But can cause diabetes!
- hPL will cause insulin resistance in mother
17
Q
During the 1st Trimester how is glucose activated from maternal reserves?
A
- Pancreatic beta cells increase in number
- Plasma insulin increases
- Fasting serum glucose decreases - laid down as stores and used by muscle
18
Q
How is glucose activated from the fetal reserves?
A
- hPL causes insulin resistance
- ie less glucose into stores
- =increased availability in serum
- glucose (more crosses placenta)
- but can cause diabetes
19
Q
What is the total water gain and from where?
A
Total water gain = 8.5L
- E2 and P act on the RAAS system
20
Q
What is the effect of E2 (oestrogen) and P (progesterone) on the RAAS system?
A
- Sodium retention
- Resetting of osmostat
- Decreased thirst threshold
- Decrease in plasma oncotic pressure (albumin) albumin levels fall due to dilutional effect = lower oncotic pressure
21
Q
Why do pregnant women breathe more deeply?
A
- Oestrogen and progesterone affect the respiratory centre in your brain
- This gives you an increased sensitivity to CO2
- Bigger + Deeper breathing - minute volume goes up by 40%
- Bigger and deeper breathing = PO2 in arteries to go up, and PCO2 to fall due to removal of extra CO2
- Allows for efficient diffusion
- High O2 levels present in mother transferred to baby and low CO2 levels in mother allow for diffusion of CO2 from foetus to mother
- Allows for efficient diffusion
22
Q
What happens to the plasma volume in maternal blood?
A
Goes up by 40-50%
- Serum plasma will go up, not red cell mass
- Can get haemodilution = apparent aneamia as Hb concentration falls
23
Q
What effect does oestrogen have on clotting factors?
A
- More clotting factors - blood becomes hypercoagulable = increased fibrinogen for placental seperation
- Increased clotting factors is said to prevent you from bleeding to death during birth
- However increased risk of thrombosis
24
Q
What is the difference between the affinity of Hb in foetal and adult blood?
A
- Foetal haemoglobin has a much higher affinity for oxygen than adult haemoglobin
- This allows for increased oxygen binding
25
What does smoking do?
* Smoking increases the carboxyhaemoglobin levels in the mother
* This has a **higher affinity for oxygen than foetal Hb**
* Causes reduced binding of foetal haemoglobin and fetal hypoxia
26
What are the cardiovascular changes which occur during pregnancy?
* Expanding uterus
* Pushes heart around
* Changes ECG and heart sounds
* Increased cardiac output
* Increased HR and stroke volume
* begins as early as 3 wks to max 40% at 28 weeks
* For maternal muscle and fetal supply
27
Why does cardiac output increase?
For maternal muscle and fetal supply
28
What are the cardiovascular changes in vessels during pregnancy?
* Increased cardiac output and **vasodilation** (due to steroids) = reduced TPR
* Increased flow to areas of the body
* Neoangiogenesis
29
Why does neoangiogenesis occur during pregnancy?
Extra capillaries in skin to assist in heat loss
30
What condition can occur in pregnancy because of the change in the CVS in vessels?
Pre-eclampsia
* narrowing of maternal spiral arteries due to release of pro-inflammatory mediators which cause endothelial cell dysfunction = vasoconstriction, hypertension, glomerular damage
31
How do steroids affect the GI tract during pregnancy?
* Appetite + thirst
* Reduced GIT motillity
* Relaxed LOS (lower oesophageal sphincter)
32
What happens when there is a reduced GIT motillity in pregnanct women?
Constipation
33
What happens when the LOS relaxes in pregnant women?
Acid reflux
Large uterus = small frequent meals
34
What dietary supplement is recommended for pregnant women?
Folic acid
* causes DNA production and growth of RBCs
35
What is deficiency of folic acid linked to?
Linked to spina bifida - neural tube defect
36
What happens to the urinary tract in pregnant women?
* Pregnancy results in relaxation of the urinary system including the kidneys, ureters and bladder.
* This can result in the **stasis of urine/ or urine** to be left behind which can result in **urinary tract infections.**
37
What happens to the kidney in pregnant women?
Increased blood flow to the kidney which increases filtration rate and increased clearance of
* Creatinine
* Urea
* Uric Acid
38
Explain the changes of the bladder during pregnancy?
n pregnancy there is an increased urinary frequency due to an increased pressure on your bladder.
This mainly occurs in the third trimester when the fetus descends into the pelvis.
39
What are the changes in uterine size?
* Increased muscle mass
* Hypertrophy of uterine muscle - not an increase in cells but hypertrophy of myometrium
* Increase in BF to placenta and uterus
40
Why are C-sections carried out on the lower uterine segment?
Less muscular and more fibrous so will bleed less
41
Primary function of the cervix?
To retain the pregnancy
42
What are the changes of the cervix?
* tissue softens from 8 weeks
* changes in connective tissue
* begins gradual preparation for expansion
* proliferation of glands
* mucosal layer becomes half of mass
* great increase in mucus production
* protective..ie anti-infective
43
What are the changes after pregnancy?
* Dramatic and rapid fall in steroids on delivery of the placenta
* Most endocrine-driven changes return to normal rapidly
* Uterine muscle rapidly looses oedema but contracts slowly: never returns to pre-pregnancy size
* Removal of steroids permits action of raised prolactin on breast
