physiological changes in pregnancy Flashcards
how does the uterus change in pregnancy?
1.Becomes bigger: increases in weight
2.Dextro-rotation:
when the uterus is tilted and twisted to the right.
occurs in 80% pregnant women
3.Lower uterine segment
forms from month 4. grows to 10cm. thats why c section scars can disappear. lower segmeent dissapears post pregnancy.
why is placing heavily pregnant women in left lateral position 30degrees important?
prevents aorta caval compression
how are maternal bones impacted by pregnancy?
many different changes occur across bones in the body, resulting in symptoms experienced by women eg neck pain, heaches, leg pain, arm pain and numbness.
All changes occur due to Relaxation of pelvic joints and ligaments caused by Progesterone and relaxin
Anterior tilt of pelvis -> sciatica + back pain
Hyperextension of knees -> foot pain
woman comes in with A butterfly pigmentation appears on the checks and nose. she is worried she may be pregnant. what is this?
Chloasma gravidarum (pregnancy mask)
It usually disappears few months after labour.
what are Striae distensae?
a type of stretch marks that occurs on skin that has been subjected to stretching and has damaged connective tissue.
purplish bands on the medial aspect of the thigh
what causes linear nigra?
pigmentation of the Linea Alba,
Due to Increased Melanocyte Stimulating Hormone - MSH
what normal changes to urine might you see on urine dip?
Glycosuria of a mild degree occurs in 35-50% of all pregnancies
what are Luteinising hormone and follicle-stimulating hormone levels in pregnancy?
undetectable
what is aorto caval compression?
Aortic caval compression from the gravid uterus impedes venous return and reduces maternal cardiac output;
abdominal aorta and inferior vena cava compressed
Why is test for maternal diabetes first conducted at 28 weeks?
Insulin resistance increases as pregnancy progresses;
develops around mid pregnancy. at this time point testing would catch 98%+ who will become resistant.
manifestation of gestational diabetes in susceptible individuals
why does insulin resistance develop in pregnancy?
driven by increase in cortisol and human placental lactogen
why is eating before labour an issue?
pregnant women have Gastric emptying is delayed.
if you add epidural or other anaesthetics to this, risk of aspiration increases
why is there an increased risk of VTE in pregnancy?
Increased coagulation factors during pregnancy
issues with anaesthetics in pregnancy?
The increased vascularity and tissue oedema in the upper airway makes intubation during general anaesthesia more difficult
what changes on urinalysis are normal for pregnant women?
Glycosuria ++
Leucocytes +
what cardiac changes are normal in a pregnant woman?
Soft systolic murmur
what is the origin of relaxin? when are levels highest?
Produced by the corpus leuteum
1st trimester
what is the origin of hcg and how do levels change in pregnancy?
Produced by the trophoblast and peak at 16 weeks gestation (thereafter fairly constant)
what is the origin of hcg and how do levels change in pregnancy?
Produced by the trophoblast and peak at 16 weeks gestation (thereafter fairly constant)
whihc hormone induces the growth of the uterus?
oestrogen
what are the types of oestrogens in pregnancy and their origin?
OVARY
- Oestrogens - in early pregnancy
PLACENTA
- Advanced pregnancy - oestrone and oestradiol
- Oestriol
FETAL ADRENALs
- Oestriol
↑ thousandfold
most abundant oestrogen in pregnancy?
oestriol
how do thyroid hormones change in pregnancy? and why
Free T4 & T3 rise but stay in normal range - in 1st trimester - because TBG is high and hCG has thyrotrophic effects
Total T4 and TBG are high and plateau at 20 wks
why is TBG high ?
production in the liver is stimulated by estrogen
as estrogen levels rise, TBG rises
thyroid binding globulin
what are thee changes ot bloods in pregnancy?
Run anaemic: 10-12g/dl instead of 12-14
WCC high
ESR high
Platelets slightly lower
Red cell count slightly lower
how is clotting risk changed in pregnancy?
↑ Concentration of factors VIII, IX, X - 8,9,10
↑ Fibrinogen levels by up to 50%
↓ Fibrinolytic activity
↓ Antithrombin and protein S levels
Left iliac vein is compressed by the left iliac artery and ovarian artery -> stasis -> virchows
when are pregnact women in a hypercoagulable state ?
1st trimester -> 6 weeks post partum
WHAT WILL THE BLOOD GAS SHOW IN A PREGNANT WOMAN AT TERM?
respiratory alkalosis with metabolic compensation
what happens to pregnant woman immune system?
T and B cell number unchanged but function suppressed = susceptible to infection.
remember wcc increases bu this is polymorphonuclear leukocytes (neutrophils & Eos/basophils)
what happens to the oxyhaemoglobin dissociation curve in
a) mother
b) fetus
mother
- Rightward shift
- increased sensitivity to 2,3 DPG
- easier unloading
fetus
- Leftward shift
- reduced sensitivity to 2,3 DPG
respiratory changes in early pregnancy are driven by?
progesterone
Pregnancy places greater demands on:
the cardiovascular or the respiratory system?
CVS
how dose cardiac output change in pregnancy?
increeases 30-50%
how do heart sounds change in pregnancy? management?
3rd heart sound present in 90%
Systolic ejection murmur - due to hyperkinetic flow
management - spontaneous resolution
what is the mechanism of physiological anaemia of pregnancy?
Total body water increases secondary to renal sodium retention (plasma volume increases most).
Renal erythropoietin increases red cell mass but still there is a resulting haemodilution and a decrease in haemoglobin concentration
what is autotransfusion and how does it help the mother?
blood from the contracting uterus compensates for the typical losses of 300-500 ml for vaginal births
and 750-1000 ml for a Caesarean section
why does blood volume increase in pregnancy?
The increased blood volume reduces the impact of maternal blood loss at delivery.
how do liveer enzymes change in pregnancy?
Alkaline phosphatase (ALP) rises with gestation due to placental production
The aminotransferases (ALT, AST) and gamma gluteryl transaminase (GGT) are reduced
Albumin falls this is partially dilutional
Bilirubin levels do not change
What are the changes in blood parameters in pregnancy?
Blood volume: ↑50%
Red cell mass:↑
FBC: ↓(Normal lower limit 10.5g/dl)
WBC: ↑ (not T and B cells)
what is the normal range of bcarbonate in pregnancy?
Results in a fall in plasma bicarbonate concentration (from 24-28mmol/L to 18-22mmol/L)
Really useful to look at, at least the final slide on this lecture
summary slide
