HTN in pregnancy/ Preeclampsia Flashcards
Types of HTN in pregnancy
- Pre-existing or chronic HTN
- Pre-pregnancy OR First recognized in 1st trimester of pregnancy - Pregnancy-induced HTN
- Presents after 20 weeks’ gestation in previously normotensive woman
- NO PROTEINURIA pregnancy-induced HTN - Superimposed pre-eclampsia
- Presents after 20 weeks’ gestation
- Exacerbation of pre-existing HTN / gestational HTN with evidence of multisystem disorder
Definition of pre-eclampsia
A multisystem progressive disorder of pregnancy characterised by
- HTN and proteinuria
- HTN and at least one end organ involvement (sx can manifest at different times)
Onset of pre-eclampsia occurs
after 20 weeks gestation
Diagnostic criteria of pregnancy-induced hypertension
BP:
- ≥140/90 on 2 occasions 4h apart OR
- ≥ 160/110 on one occasion
NO Proteinuria in PIH but for pre-eclampsia:
- ≥0.3g/24h OR
- Spot urine protein:creatinine ratio ≥30 mg/mmol OR
- Dipstick proteinuria ++ or more (in the absence of UTI)
*cut-off is only applicable to women NOT on anti-hypertensives
*if mother is already on anti-hypertensives, look at trend instead
Definition of eclampsia
Grand mal seizure activity and/or unexplained coma in a woman with signs or symptoms of pre-eclampsia, due to cerebral vasoconstriction
Risk factors of pre-eclampsia
REVIEW risk factors at booking visit
HIGH RISK:
- Previous pre-eclampsia or gestational hypertension
- Pre-existing hypertension
- Pre-existing kidney disease
- Diabetes Mellitus
- Anti-phospholipid syndrome
- SLE
MODERATE RISK:
- Maternal age 40yo and more, teenager
- First pregnancy
- New partner
- Pregnancy interval of more than 10 years
- BMI of 35kg/m2 or more
- FHx of pre-eclampsia in mother/ sister
- Multi-fetal pregnancy
- IVF
Protective RF of pre-eclampsia
Smoking
What are the indications to qualify for prophylaxis?
Only ONE high risk factor is needed to qualify for prophylaxis OR 2 moderate risk factors
Pathophysiology of pre-eclampsia
Spiral artery remodelling that occurs between 12-30 weeks of gestation
In pre-eclampsia, there is incomplete transformation of spiral artery and after 20 weeks there will be no more transformation, signs and symptoms will start to manifest and cannot be undone
Shallow extravascular trophoblast invasion into maternal tissues + Incomplete transformation of spiral artery
-> placental hypoxia
Organs affected in pre-eclampsia and accompanying symptoms
Brain
- Headache
- Visual disturbances (BOV/ flashing of lights)
- Clonus and brisk deep tendon reflexes
Lungs
- Pulmonary edema
- Pulmonary embolism
Heart
- CHF
Liver
- N/V
- Epigastric pain
Kidney
- Oliguria
- Proteinuria
Fetus
- IUGR
Malplacentation
- Reduced fetal movements
- Placenta abruptio: abdo pain, vaginal bleeding
Blood
- Thrombocytopenia
- DIVC
Oedema
- Swelling (extremities/ face/ sacral)
- DVT
Severe forms of HTN disorders
- HELLP syndrome
- Haemolysis
- Elevated Liver enzymes
- Low Platelets
*can occur in the absence of HTN and proteinuria
- Eclampsia
Prophylaxis for pre-eclampsia
If patient has ONE high risk factor OR 2 moderate risk factors, START:
- Low dose aspirin (100-150mg every night) (150mg nowadays)
- Start between 12-16 weeks of gestation - Calcium supplementation (1.5-2g daily) if low dietary calcium
Early detection and monitoring: MATERNAL
- Regular antenatal checks
- BP
- Dipstick proteinuria - Symptom review
- Low threshold to perform further ix if suspicious
- Bloods: FBC, LFT, RP
- Quantify proteinuria: 24h proteinuria >0.3g/24h (conventional) or spot urine protein creatinine ratio >30 mg/mmol
Early detection and monitoring: FETAL
- Fetal movements
- Serial symphysio-fundal heights
- Fetal heart auscultation
- Ultrasound scanning
What is assessed for during the ultrasound screening of fetus?
Findings in Malplacentation
Late 2nd trimester:
- Maternal uterine artery doppler: uterine artery doppler notching (uteroplacental perfusion screening test)
In 3rd trimester:
- Fetal growth (biometry – Head Circumference, Abdominal Circumference, Femur Length, calculate estimated fetal weight)
- Umbilical artery dopplers (fetal perfusion of placenta)
- Middle cerebral artery dopplers (proxy of fetal oxygenation)
- Amniotic fluid (Oligohydramnios may indicate placental insufficiency)