Week 4- hypertension in pregnancy Flashcards
what are the CV changes during pregnancy?
Heart: rotates up and to the left 1-1.5 cm
Increased CO by 30 and 50%-
early pregnancy increased CO due to increased SV-pre load increased due to increased BP and afterload reduced due to decrease SVR
Late pregnancy0 increased CO due to increased HR
what is the timeline of CVS chages per trimester?
1- maternal systemic vasodilation]SVR progressivly drop 30/40%
CO begins to rise
HR begins to slowly rise
2- plataeu in SVR
CO continues to rise
HR increased
3- CO peaks in early third trimester 30-50% above baseline
HR peaks in late 3rd trimester - 16 bpm above non-pregnant values
what chages occur to the plasma volume during pregnanacy? why?
increases slowly from the third trimester, then expands rapidly from 30-34 weeks
this protects mum and baby, meets foetal nees, assists in perfusion and safegaurds agains blood loss at delivery
what are the changes to red blood cell mass during pregnancy? why?
begins to increase at 8 weeks and steadily rises
Supports higher metabolic requirment for oxygen during pregnancy
results in haemodilution causing anemia
what are the changes to BP in pregnancy?
Aterial BP decreases due to decreased Peripheral resistance
lowest in 2nd trimester- neraly normal by term
DEcreases diastolic by 10-15mmhg by 24 weeks
Systolic usually unchanged- decreases a max of 5-10 mmgh
pre-pregnant values return by thrid trimseter
what is supine hypotension in pregnancy?
supine position reduces CO, SV and increases HR
- due to compression of the aorta and inferior vena cava from the enlarging uterus
overcome by left lateral tilt to shift uterus off the aorta and IVC
what are the three clasifications of hypertension in pregnancy?
Chronic
non-proteinuric induced hypertension (gestational)
Pre-eclampsia- eclampisa and HELLP syndrome
what is the definition and risk factors for chronic hypertension?
Hypertension prior to pregnancy or increased BP above 140/90 before 20 weeks
Persistes up to 6 weeks post natal and may continue if pre-exisitng
Risk factors- renal diseas, diabetes, obestiy age >40 and HTN on the OCP
what is the definition and ris factors for gestational hypertension?
hpypertension >140/90 on >2 occasion
no other sings of pre-eclampsia
occures >20 wees
risk factors- primiparity/first child with new partner
obestiy, diabetes, preveious sevre pre-eclampsia, pre-existing CVD and age >40
what is the definition of pre-eclampsia?
Hypertension after 20 weeks plus any:
Renal, liver, heamotological or neurological involvment
what renal involvment may be seen with pre-eclampsia?
significant proteinuria- protien/creatinin ration >= to 30 mg/mol
Serum/plasma creatinin >90micromol/L
Oliguria: <80ml/4 hours
what liver involvement may be seen with pre-eclampsia?
abnormal LFTs
Sevre epigastric RUQ pain
what heamotological involevment may be seen with pre-eclampsia?
thrombocytopnia
heamolysis
DIC
what neurological involvment may be seen with pre-eclampsia?
convulsions (eclampsia) hyperflexia new headache visual disturbances stroke
what are the risk factors for pre-eclampsia?
First pregnanacy multiparous witha hx of pre-eclampsia pre0eclmapsia in previous pregnancy 10 years since last baby >40 years old
what are the statistics for mild and sevre pre-eclampsia?
mild- 5-10 pregnancies
sevre- 1-2 %
what percenage of induced and c-section labours are due to pre-eclampsia?
20% induced
15% c-section
how many people die of eclampsia die world-wide annually?
50-75000
What is the pathophysiology of pre-eclampsia?
Still unknown
abnormal placenta- with normal trophoblastic invasion of the spiral arteries inhibited- impeeding poetoplacental pressure system-leading to placental hypoxia
what are trophoblasts and what do they do?
cells that develop into the placenta and provide nutrients to embryo- help to make spiral artiers less thick and more maliable which allow high flow and low pressure
what occurs during phase one of pre-eclampsia?
insufficent/pathcy relase of trophoblasts causinf aprial artiers to uteroplacental remain ridged leading to high pressure and low flow.
the reduced flow leases to ishemia of the uteroplacntal spiral artiers
what occurs during phase two of pre-eclampsia?
Inflmation and tress response due to ischemia
leading to endothelia dysfunction (leaky vessles), vasospasm and activation of the coagulation system: symptoms we see
what are the pathological changes due to pre-eclampsia on the blood/cardiovascular system?
Hypertension with endothelia cell damage affecting capilary permiability
Plasma proteins leak- plasma colloid pressure drop and odeam
what are the pathological changes due to pre-eclampsia on the coagulation system?
Altered coagulation cascade, increased platlet consuption- thrombocytopenia. DIC - Occlude kidneys: brain, liver and placenta
