Pregnancy Flashcards
Which macromolecules increases in the pregnant mother’s circulation?
Lipids
Why is there increased loss of electrolytes like Ca from the pregnant mother?
Increased GFR
What is involved in insulin resistance in gestational diabetes?
Placental lactogen
What is DHA?
The precursor of all oestrogens pregnancy
Functions of oestrogens?
Increase the liver synthesis of lipids and cholesterol Growth and priming of the uterus Anti-insulin Cervical ripening Stimulated of RAAS
Functions of progesterone?
Maintains endometrium (D0-60 is c. luteum then placenta)
Suppresses mat immune response to fatal antigens
Partuition
Substrate for fetal adrenal production
Inhibits uterine contractility and ripening
Inhibits over breathing
Stimulates RAAS
Growth of mammary glands
Function of hCG:
Binds to TSH receptors and increases metabolic rate
Function of hPL:
Lipolysis Anti-insulin Protein synthesis Gluconeogenesis Neovascularisation
Cortisol?
Increases
Cardio changes:
Heart rate increases
Cardiac output increases
Total peripheral resistance decreases
Blood pressure decreases early in the pregnancy
What causes increased secretion of aldosterone?
Oestrogen
Progesterone
Prostaglandins
What causes increased sympathetic tone and renin release in pregnancy?
Shunting of blood to the uterine circulation
Also increased GFR resulting in Na loss as well as hCG increases renin secretion
GFR pattern in pregnancy:
GFR rises sharply over pregnancy until the 26th week where it decreases (renal plasma flow mirrors)
Renal changes in pregnancy:
Reduced plasma concentration of urea and creatinine
Glycosuria
Calciuria
Frequency
Stasis due to dilatation of the collecting system
Pulmonary changes in pregnancy:
FRC decreases 20% by term Expiratory reserve volume down 30% by term Tidal volume increases 30-40% by term Residual volume reduces 20% by term - SOB pCO2 decreases (progesterone) Increase in pO2 pH unchanged Decrease in bicarbonate
Vascular changes in pregnancy:
Slight increase in coagulability - for delivery Increase in Factors VII, VIII and X Increase in plasma fibrinogen Increased ESR Decreased fibrinolytic activity
Smooth muscle changes in pregnancy:
Decreased tone causing biliary stasis, reflux and increased absorption
Gas exchange in the pregnancy:
Maternal uterine artery: mmHg
pO2 = 95, pCO2 = 35
Fetal umbilical artery: mmHg
pO2 = 24, pCO2 = 50
Where does the fetus get insulin?
It produces its own fetal insulin from weeks 9-11 - doesn’t not get in from the mother
What is the ductus venosus?
Duct bypassing the liver
What is the foramen ovale?
Opening from the right to the left heart
What is the ductus arteriosus?
Duct from the pulmonary artery to the descending aorta
only 20% of the fetal circulation reaches the lungs
What is the fatal circulatory response to hypoxia?
Heart rate falls
Resistance in the umbilical cord increases
Resistance in the MCA decreases to protect fetal brain
Blood flow to the heart and adrenals increases
Blood flow to the kidneys decreases (reduced amniotic fluid vol)
What effects on foetal physiology does delivery have?
Cord occlusion decreases right atrium pressure so f. ovale closes
Inspiration causes vasodilation of the pulmonary artery and decreased resistance through f. ovale and ductus a.
Increased PaO2 leads to closure of ductus a.
What modulates ductus arteriosus closure?
Prostaglandin E2 + prostacyclin delay duct closure
NSAIDs accelerate duct closure
What stimulates the synthesis, specialisation and release of surfactant as well as lung lipid resorption and epithelial cell differentiation from 30 weeks?
Cortisol
How is foetal PaO2 only 30mmHg?
Compensated by high binding affinity of HbF for O2
(switch to HbA happens at 28 weeks
What can be used to clear liquid from the lung?
Opening of ENaC with ADH or adrenaline - reverses osmotic gradient
What is partuition?
Birth in labour
Softening and effacement of the cervix
Contractions
Stage 1 of labour:
3 contractions every 10 minutes
Stage 2 of labour:
Cervix fully dilated at 10cm
Strong contractions
Stage 3 of labour:
Placenta delivered due to oxytocin (oxytocin and ergometrine can be given artificially)
What can stimulate contraction?
Baby moving
Giving PGE2 and oxytocin
Effect of cortisol in pregnancy:
Increases placental CRH Increases oxytocin Increases prostaglandins Increases fatal membrane production Stimulates conversion of DHEAS to oestrogen
How do suckling stimulate prolactin secretion?
Increase in VIP resulting in decreased dopamine release
How does suckling stimulate milk ejection?
Paraventricular and supraoptic nuclei release oxytocin
First trimester:
Week 1 to (end of) 12
Second trimester:
Week 13 to (end of) 26
Third trimester:
Week 27 to the end of the pregnancy
Cardio changes in the first trimester:
SVR down BP down (110/60 is normal) CO up (110 is not normal) SV up
Cardio changes in the second trimester:
SVR down
BP down
CO up
SV up
Cardio changes in the third trimester:
SVR is beginning to rise by term
BP rises back to where it was before the pregnancy
CO is variable
SV is up
Cardio changes intrapartum:
SVR down
BP variable
CO up
SV up
Cardio changes early post-delivery:
SVR up
BP up
CO up
SV up
Cardio changes late > 2/52
SVR up
BP variable
CO Down
SV down
ABGs:
Respiratory alkalosis is normal with no change in base excess and reduced bicarbonate
Pregnant woman with chest pain - investigation?
CT or perfusion lung scan to find a clot
Why does ADH release decrease?
Placental vasopressin
LH and FSH in pregnancy?
Virtually undetectable
Suppressed by high levels of oestrogen and progesterone
GH in pregnancy?
Increases
Placental growth factors
ACTH in pregnancy?
2-fold increase in the first trimester
No change in pituitary production but there is placental production of cortisol releasing factor
IGF-1 in pregnancy?
Increases
Stimulated by hPL (human placental lactogen)
ADH in pregnancy?
Reduction in circulation
Production of placental vasopressinase
Prolactin in pregnancy?
Progressive increase
Stimulated by oestrogen
Little enters circulation from decidual tissue
Renin in pregnancy?
Increase 4-fold by 20 weeks then plateaus
RAAS activation results from the drop in TPR and resultant drop in after load
Aldosterone in pregnancy?
Increase 3-fold in 1st trimester and 10-fold by the third
Response to increased renin and angiotensin II
Thyroid hormones in pregnancy?
Higher total levels of T4 and T3, mother needs to make 50% more
Increased renal iodine clearance and fatal iodine uptake
1st trimester there is increased T4 which suppresses TSH
hCG also activates TSH receptors
Heamodilution also helps explain why more is made
Cortisol in pregnancy?
Increase 3-fold
Suppression by exogenous corticosteroid is blunted
Due to increase in cortisol binding globulin, cortisol releasing hormone and progesterone
How is pre-eclampsia defined?
Gestational hypertension past 20 weeks (sys or dia over 140/90)
With one of:
1) Proteinuria
2) Systemic involvement (e.g. renal indicated by elevated creatinine)
3) Foetal growth restriction
What can be the systemic complications of pre-eclampsia?
Signs
Cerebral or visual disturbance
Impaired renal function (creatinine >1.1mg/L or doubled)
Pulmonary oedema
Liver dysfunction (transaminase twice normal amount)
Thrombocytopenia - platelets <100,000/uL
What is HELLP?
It is a non-hypertensive subtype of pre-eclampsia
H - Haemolysis
EL - Elevated liver enzymes
LP - Low platelets
Risk factors for pre-eclampsia?
Primiparity Multiple pregnancy Previous occurence/FH Pre-gestation diabetes PCOS AI conditions Renal disease Chronic hypertension or gestational hypertension BMI >30, age >35
Symptoms of pre-eclampsia?
Headache (frontal) Right upper quadrant pain Visual disturbances (photopsia, retinal vasospasm, scotomata) Breathlessness Seizures Oliguria
Investigations to be done in pre-eclampsia:
Urinalysis for protein
Foetal ultrasound
Umbilical artery Doppler velocimetry
Coagulation screen if platelets <100,00/uL
Differentials for pre-eclampsia:
Other forms of hypertension
Epilepsy
Anti-phospholipid antibody syndrome (Hx of repeated early pregnancy loss)
Management before delivery:
1) Admission and monitoring \+ decision regarding monitoring Adjunct: corticosteroid \+ (w/ BP >160/110) anti-hypertensive \+ (w/ seizures) magnesium sulfate
Management after delivery:
1) Close monitoring of fluid balance
+ continue anti-hypertensives and magnesium sulphate
Appropriate management for a woman with 3 risk factors for thromboprophylaxis?
LMWH from 28 weeks to 6 weeks post natal
Risk factors for thromboprophylaxis in pregnancy:
Age>35, BMI>30, Parity>3 Smoker, gross varicose veins Current pre-eclampsia, immobility FH of unprovoked VTE Low risk thrombophilia Multiple/IVF pregnancy
Appropriate management for a woman with >3 risk factors for thromboprophylaxis?
Immediate LMWH
Which thrombolytic drugs should be avoided in pregnancy?
DOACs and warfarin
Diagnosis of DVT shortly before pregnancy management?
Continue anticoagulation treatment for 3 months postpartum
Causes of primary postpartum haemorrhage?
The 4 T's: Tone (uterine atony) Tissue (retained products of conception) Trauma (to the genital tract or perineum) Thrombin (coagulation abnormalities)
Secondary PPH?
24 hours-12 weeks
Due to retained placental tissue or endometritis
Risk factors for shoulder dystocia?
Fetal macrosomia
Diabetes mellitus
Premature labour
High maternal BMI
What can happen as a result of shoulder dystocia?
Brachial plexus injury in the newborn such that they cannot move their arm properly and it is fixated medially
Perineal tears to the mother
Effect of maternal diabetes mellitus on fetus?
Insulin resistance
Polyuria
Polyhydramnios
Macrosomia
Effect of rhesus incompatibility of newborn?
Hydrops fetalis (effusions, loss of oncotic pressure as liver is trying to primarily produce for RBCs)
Jaundice, anaemia, hepatosplenomegaly
HF
Kernicterus (brain damage from jaundice)
Treatment for rhesus incompatibility:
Anti-D Ig
For the baby: transfusions and UV phototherapy
When is the baby at risk of rhesus incompatibility?
If the mother is rhesus negative and the baby is rhesus positive
Effect of gestational diabetes?
Macrosomia (child is large) and infant hypoglycaemia as the child will have developed large amounts of insulin to deal with the high glucose concentrations in the mothers blood
Determinant of foetal growth?
Insulin
Determinant of infant growth (0-2 years)?
Nutrition and insulin
Determinant of childhood growth (3-11 years)?
Growth hormone and thyroxine
Determinant of growth in puberty (12-18 years)?
Growth hormone and sex steroids
