Physiology in Pregnancy Flashcards
Give 3 ways to estimate the date of delivery.
Use Naegele’s rule: add 7 days to 1st day of LMP, subtract 3 months, add 7 days, add 1 year. Ultrasonic examination - measurement of crown-to-rump length in first trimester. Measure of fundal height - from the pubic symphysis to highest part of the uterus (reaches umbilicus at 20 weeks).
What is Naegele’s rule?
Add 7 days to 1st day of LMP, subtract 3 months, add 7 days, add 1 year.
How is the fundal height measured?
From the pubic symphysis to highest part of the uterus .
What happens to blood volume during pregnancy?
Increases up to 40 weeks. Once placenta out, it drops.
What happens to stroke volume, heart rate and cardiac output during pregnancy?
All increase.
Why does blood pressure decrease during pregnancy?
Due to progesterone-induced vasodilation; BP = CO × systemic vascular resistance (SVR).
What happens tidal volume, oxygen consumption and basal metabolic rate during pregnancy?
All increase.
Mild respiratory alkalosis is as a result of what during pregnancy?
Hyperventilation.
Why do pregnancy patients become anaemic during pregnancy?
Plasma > RBC volume → hemodilution. ↓ hematocrit (ratio of the volume of red blood cells to the volume of blood - physiologic anemia.
Why do bicarbonate ions fall during pregnancy?
They are excreted from the kidneys as renal compensation for respiratory alkalosis.
Give 2 gastrointestinal symptoms of pregnancy.
Nausea. Vomiting (AKA “morning sickness” ). Constipation. Heartburn (pyrosis). Oesophageal reflux. Intrahepatic cholestasis of pregnancy due to ↓ gallbladder emptying time → ↑ risk of cholelithia (impair release of bile from liver cells).
Why is there nausea in pregnancy?
Reduced peristalsis.
What happens to progesterone levels, kidney size and kidney volume during pregnancy?
All increase.
Why does urinary frequency increase during the first trimester of pregnancy?
Gravid uterus presses on bladder → urinary frequency, nocturia, stress incontinence.
Why does urinary frequency decrease during the second trimester of pregnancy?
Second trimester: uterus occupies abdominal space → ↓ urinary frequency
Why does parathyroid hormones increase during pregnancy?
Increase in parathyroid hormone (PTH) ensures regulation of serum calcium (meets calcium need of developing fetal skeleton).
Why are FSH and LH levels almost undetectable during pregnancy?
High levels of oestrogen and progesterone.
What happens to aldosterone and renin levels during pregnancy?
Both increase to increase blood volume.
What stimulates prolactin to rise during pregnancy?
Oestrogen stimulates pituitary prolactin release.
Why do cortisol levels rise during pregnancy?
Physiologic hypercortisolism ▫↑ need for estrogen, cortisol → ↑ glucocorticoids from adrenal glands →supports fetal somatic, reproductive growth.
What happens to the pancreas during pregnancy?
Hypertrophy. Diabetogenic state” of pregnancy ▫↑ need for glucose, insulin production →hypertrophy, hyperplasia of pancreatic beta cells.
