Maternal Changes In Pregnancy Flashcards
What are the reasons for changes in pregnancy?
→ High levels of fetal steroids
→ Mechanical displacement
→ Fetal requirements
What kind of an event is pregnancy?
→ Physiological
What can pregnancy do physiologically to existing conditions?
→ Exacerbate an existing condition
→ uncover a hidden or mild condition
What are 6 changes that occur during pregnancy?
→ Increase in uterus size
→ Increase metabolic requirements of the fetus
→ Structural and metabolic requirements of the fetus
→ Removal of fetal waste products
→ Prevision of amniotic fluids
→ preparation for delivery and puerperium
In what systems do pregnancy changes occur?
→ Respiratory system
→ Cardiovascular system
→ GI
→ Urinary
→ Endocrine
What are the three placental peptides?
→ hCG, hPL, GH
What takes over progesterone production?
→ Corpus luteum
What is the corpus luteum kept alive by?
→ hCG
What are the placental and fetal steroids?
→ Progesterones
→ Estradiol
→ Estrogen
What 4 hormones induce insulin resistance?
→ Growth hormone
→ Corticotropin releasing hormone
→ Estrogen
→ Human placental lactogen
Why do you want the myometrium to be quiescent?
→ Contractions would cause miscarriage
What is the total weight gain during pregnancy?
→ 12.5 - 13kg
What is the breakdown of the weight gain during pregnancy?
→ Fetus + placenta - 5kg
→ Fat and protein - 4.5kg
→ Body water 1.5kg
→ Breasts - 1kg
→ Uterus 0.5-1kg
Where is fat mainly laid down?
→ Anterior abdominal wall
What does the basal metabolic rate rise by in mid and late gestation?
→ 350kcal/day - mid
→ 250kcal/day - late
How does glucose get to the fetus?
→ Facilitated diffusion across the placenta
Where does the fetus store glucose?
→ in the liver
Describe what happens to maternal glucose reserves in the first trimester
→ Pancreatic ß cells increase in number
→ plasma insulin increases
→ Fasting serum glucose decreases (laid down as stores and used by muscle)
Describe what happens to fetal glucose reserves in the second trimester
→ hPL causes insulin resistance
→ less glucose into stores
→ increases availability in serum glucose so more crosses the placenta
Describe how gestational diabetes occurs
→ Hormones antagonise the effects of insulin
→ Insulin increases
→ Beta cells become hypertrophied
→ Glucose is going into cells to be stored
→ insulin resistance gets higher due to hPL
→ The body makes more insulin to overcome the resistance
→ if you are already obese and insulin resistant you get gestational diabetes
Describe how water gain occurs in pregnancy
→ Estrogen and progesterone activate the RAAS system
→ Sodium is retained
→ Plasma volume increases by 40-50%
→ A litre of amniotic fluid is made
Why do you breathe quicker and deeper during pregnancy?
→ Estrogen and progesterone increase respiratory sensitivity to CO2
What does the minute volume increase by?
40%
What is gas transfer like between mother and fetus
→ high O2 in mothers blood it favors transfer to the fetus
→ high CO2 in fetus it goes to the mother
What does the plasma volume increase by?
→ 40-50%
How does Hb concentration change in pregnant women?
→ it decreases
→ Red cell count goes up by 20% but the plasma goes up by 40% so the Hb is more diluted
How is more iron absorbed?
→ Transferrin
Why do you become hypercoagulable?
→ clotting factors increase
→increased fibrinogen for placental separation, but increased risk of thrombosis
What does smoking do to fetal blood?
→ Increases maternal carboxy-Hb which reduces binding of O2
→ fetal hypoxia
How is blood transferred from the mother to the fetus?
→ Fetal blood has increased Hb
→ Increased O2 binding
→ Oxygen is given up by maternal Hb
How much does cardiac output increase by?
→ 40-50%
What is preeclampsia?
→ High blood pressure
What is blood pressure like during pregnancy and why?
→ Blood pressure = peripheral resistance x CO
→ if CO goes up by 40-50% the blood pressure must go down
→ peripheral resistance must decrease
→ HIGH VOLUME AND LOW PRESSURE
Where does blood flow increase?
→ Uterus
→ Placenta
→ Muscle
→ Kidney and skin
Why does neoangiogenesis occur?
→ Extra capillaries in skin to assist with heat loss
How does acid reflux occur?
→ in the third trimester the LOS tends to relax
What does progesterone do to the GI tract?
→ Increases appetite
→ Smooth muscle relaxation throughout the whole gut
→ a common side effect is constipation
What does deficiency of folic acid lead to?
→ Spina bifida - neural tube defect
How much folic acid should be taken?
→ 5mg/day upto week 12
Why do pregnant women get UTIs?
→ If you ultrasound a pregnant woman’s kidneys they are dilated
→ You may not void everything and get static urine and get UTIs
How much does the filtrate increase by and why?
→ 40-50% because all the cardiac output goes through the kidney as well
Why is there increased frequency in urination during pregnancy?
→ Baby’s head is pressing on the bladder in very late pregnancy
What does the uterus hypertrophy in response to?
→ Estrogen
Where is the incision for a C section done?
→ Just above the symphysis
When does the cervix tissue soften?
→ From 8 weeks
What is the function of the cervix?
→ To retain the pregnancy
What happens to the glands in the cervix?
→ Great increase in mucus production
→ Anti-infective
What happens when the placenta is delivered?
→ Rapid fall in steroids
What happens to the uterus after delivery?
→ Rapidly loses oedema but contracts slowly
→ Never returns to pre-pregnancy size
What enables prolactin?
→ Removal of steroids
What are the maternal and fetal pituitary hormones?
GH, thyroid hormones, prolactin, CRF
What happens to uterine muscle after delivery?
→rapidly looses edema but contracts slowly: never returns to pre- pregnancy size
