Complications of pregnancy Flashcards
What condition is defined as “persistent severe vomiting leading to weight loss and dehydration, as a condition occurring during pregnancy”?
Hyperemesis Gravidarum
What cardiovascular changes occur during pregnancy?
⇧Ventricular wall muscle mass
⇧ Myocardial contractility
⇧ Stroke volume
⇧ Heart rate (minor – 10-20bpm)
⇧ Peripheral vasodilation
-25-30% drop in systemic vascular resistance
⇧ Cardiac output
-20% within first 8 weeks
-Maximum at 20-28 weeks (40%)
Reduced colloid oncotic pressure (10-15%)
Is oedema a concern in pregnancy?
Most pregnant women will be oedemitous, due to a decrease in colloid osmotic pressure however it is only a concern when the swelling is rapid and around the face, neck or chest - this can be a sign of pre-eclampsia
Why should you avoid positioning pregnant patients supline, how is this managed in resuscitation?
It can cause compression of the inferior vena cava:
-reduction in venous return to the heart
-stroke volume and cardiac output reduced (by up to 25%)
-reduction in uterine blood flow & placental perfusion
In resuscitation they will be led supline and left uterine displacement will be used
What is Pregnancy Induced Hypertension (PIH) and what causes it?
Defined as a ersistently elevated BP >20 weeks gestation (>140/90)
No specific cause identified
What are the dangers of Pregnancy Induced Hypertension (PIH)?
Blood vessel damage
Increased risk of cardiac failure and CVA
How does pregnany affect the respiratory system?
⇧Oxygen demand
15% ⇧ in basal metabolic rate
20% ⇧ in oxygen consumption
Diaphragmatic elevation (uterus displaces it)
-Reduced functional residual capacity but no change in diaphragmatic excursion or vital capacity
SoB on exertion is normal for pregnant patients but acute, prolonged SoB or desaturation is abnormal
What are the GI affects of pregnancy?
Most common is nausea and vomiting (morning sickness - 50-90% incidence)
-Hyperemesis Gravidarum
Decreased motility in the digestive tract
What are the dangers of Hyperemesis Gravidarum?
Dehydration
Weight loss
Electrolyte imbalances
Compromises foetus nutrition
What causes morning sickness?
It is thought to be a protective mechanism to protect the early foetus from anything harmful, it is associated with high levels of hCG (hCG rises rapidly at the beginning of pregnancy, falls in hCG levels are associated with a reduction in morning sickness)
What are the causes and effects of reduced digestive tract motility in pregnant patients?
Caused by increased progesterone (smooth muscle relaxant)
Can cause:
-Slow emptying of stomach
-Reflux
-Bloating
-Haemorrhoids/fissures
-Constipation
How does pregnancy affect blood volume?
There is an increased in blood volume
-Plasma up 50%
Usually no change in MCV (mean corpuscular volume) or MCHC (mean corpuscular haemoglobin concentration)
What increases more during pregnancy RBCs or plasma? What effects does this have?
Plasma increases more
-Fall in Hb, RBCs and haematocrit causes relative anaemia and symptoms thereof
How does pregnancy affect platelet count?
Pregnancy causes a progressive fall in platelet count
A significant drop - classed as thrombocytopenia - Can indicate preeclampsia, HELLP, or ITP (idiopathic thrombocytic purpura)
What is HELLP syndrome?
HELLP (Haemolysis, Elevated Liver enzymes and Low Platelets) syndrome is a life-threatening pregnancy complication usually considered to be a variant of preeclampsia.
How does pregnancy affect demand for iron, folate and vitamin B12?
2-3x increase in demand for iron
-Haemoglobin synthesis
-Foetal development
10-20 x increase in demand for folate
-DNA, RNA, metabolises amino acids
2 x increase in demand for vitamin B12
What causes pregnant women to be in a constant hypercoaguable state?
Increased clotting factors VIII, X and XI
50% increase in fibrinogen
Decrease in fibrinolytic activity
Decreased endogenous anticoagulants
For how long are pregnant patient at an increased risk of clotting and venous thrombosis?
From first trimester until 12 weeks post-partum
What is pre-eclampsia?
Persistent hypertension associated with high protein urine levels in pregnant or recently pregnant women, a precursor to eclampsia
What is eclampsia?
A condition in which one or more convulsions occur in a pregnant woman suffering from high blood pressure, often followed by coma and posing a threat to the health of mother and baby.
When can pre-eclampsia affect women?
From 20 weeks gestation up to 6 weeks after delivery
Are the symptoms of pre-eclampsia severe or mild?
It can range from asymptomatic to mild to severe or life threatening symptoms
What is the significance of high proteinuria in pre-eclamptic patients?
It is a sign of kidney damage, and can damage other organs
What are the risk factors for pre-eclampsia?
First pregnancy
Multiple gestations (twins etc.)
Age > 35
Existing hypertension
Diabetes
Obesity
Family history
What is the pathophysiology of pre-eclampsia?
The exact cause in unknown.
It is linked with placental abnormalities, specifically in the utero-placental arteries which should expand during pregnancy.
In pre-eclampsia these arteries become fibrous and cannot expand enough causing a poorly perfused placenta which leads to intrauterine growth restriction and possibly placental abruption or foetal death.
The fibrous arteries release inflammatory proteins which enter the mothers circulation and cause endothelial damage causing vasocontriction and salt retention in the kidneys.
There can also be areas of isolated vasospasm which can cause oliguria if present in the kidneys, visual disturbances in the eyes, or liver injury and swelling contributing to right upper quadrant pain and HELLP syndrome.
Endothelial damage also causes the blood vessels to become more permeable, this combined with the lower colloid osmotic pressure in the blood caused by proteinuria leads to excessive water loss into the tissues. This results in generalised, pulmonary and possibly cerebral oedema.
Which blood pressure values define pre-eclampsia and severe pre-eclampsia?
Pre-eclampsia: BP>140/90
Severe pre-eclampsia: BP>160/110
What can hypertension in severe pre-eclampsia lead to?
Haemorrhagic stroke
Placental abruption
What is the pathophysiology of HELLP syndrome?
Endothelial cell injury leads to thrombi formation in the blood using lots of platelets, circulating RBCs can collide with these thrombi causing haemolysis and low platelets.
Hepatic vasoconstriction/vaso-spasm causes elevated liver enzymes
What percentage of patients with severe pre-eclampsia/eclampsia will develop HELLP syndrome?
10-20%
What are the symptoms of pre-eclampsia?
BP > 140/90
Upper right quadrant pain
Headache
Nausea and vomiting
Oedema in face, neck or chest
Pulmonary oedema
Visual changes
Nose bleeds
How does DIC occur in pregnancy?
Pre-eclampsia and placental abruption can cause increased clotting. This leads to excessive consumption of clotting factors and subsequent haemorrhage/DIC.
