Maternal Changes in Pregnancy Flashcards
What are the causative factors in the changes in pregnancy?
- High levels of steroids
- Mechanical displacement
- Fetal requirements
What can pregnancy do for other conditions?
- Exacerbate a pre-existing condition
- Uncover “hidden” or mild condition
What are the changes in pregnancy that are 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 are their changes in during pregnancy?
- Energy balance
- Respiratory system
- Cardiovascular system
- Gastrointestinal system
- Urinary system
- Endocrine system
Which hormones cause most of the changes in the maternal body?
- Placental peptides
- Maternal steroids
- Placental and fetal steroids
- Maternal and fetal pituitary hormones
What are the placental peptide?
hCG - keeps the corpus luteum alive
hPL
GH
When does the placenta take over ovarian production?
At week 7
What are the placental and fetal steroids?
Progesterone
Oestradiol
Oestriol
What are the maternal and fetal pituitary hormones?
GH
Thyroid hormones
Prolactin
CRF
What do the placental steroids affect?
- Renin/angiotensin system
- Respiratory centre
- GI tract
- Blood vessels
- Uterine myometrial contractility
Breakdown for total weight gain during pregnancy
13kg
- Fetus plus placenta = 5kg
- Fat and protein = 4.5 kg
- Body water = 1.5 kg
- Breasts = 1 kg
- Uterus = 0.5 - 1kg
When does weight gain need monitoring?
- Failure to gain or sudden change needs monitoring
Why does energy output during pregnancy need to be increased?
- To cope with increased respiration and cardiac output
Why does energy storage during pregnancy need to be increased?
- For fetus
- For labour and puerperium
Why does the body gain 4-5kg in fat and protein stores?
- Increased consumption and reduced use
- Mainly laid down in anterior abdominal wall
- Utilised later in pregnancy and puerperium
How much does the basal metabolic rate (BMR) rise by during mid gestation per day?
350 kcal per day
75% fetus and uterus
How much does the BMR rise during late gestation per day?
250 kcal per day
25% respiratory
How does the need for glucose increase in the 2nd trimester?
- Increased availability
- Active transprot across placenta as fetal energy source
- Fetus stores some in liver
During the 1st trimester, how is glucose activated from the maternal reserves?
- Pancreatic beta cells increase in number
- Plasma insulin increases
- Fasting serum glucose decreases (laid down as stores and used by muscle)
During the 2nd trimester, how is glucose activated from the fetal reserves?
- hPL causes insulin resistance i.e. less glucose into stores
- Increased availability in serum glucose (more crosses placenta) but can cause diabetes
What is the total weight gain and from where?
- 5L
- Placenta
- Amniotic fluid
- Oedema
- Uterine muscle
- Mammary gland
- Plasma volume
- Fetus
What acts on the renin angiotensin system?
E2 and Progesterone
How does E2 and progesterone affect the RAAS?
Sodium retention, resetting of the osmostat, decrease thirst threshold, decrease in plasma oncotic pressure (albumin).
Why do pregnant women breathe more deeply?
- This increases the respiratory centre sensitivity to CO2.
- The thoracic antomy changes and the ribcage is displaced upwards and the ribs flare outwards.
- This increases the minute volume increases 40%.
- The arterial PO2 increases 10%; PCO2 decreases 15-20%
- This facilitates gas transfer so the baby receives more O2 from the maternal blood.
