Pre-eclampsia is pregnancy disorder which occurs in approximately 2-8% of pregnancies and is considered one of the most dangerous and unpredictable complications of pregnancy. It usually presents in the second or third trimester and is characterized by hypertension (high blood pressure) and multi-organ system involvement.
There are striking differences in disease progression between women, for some women pre-eclampsia can present as a mild condition which may develop slowly over time, or it can progress quickly into a life-threatening disorder.
Currently, the diagnoses for pre-eclampsia is:
- New onset of high blood pressure (BP>140/90 during pregnancy and postpartum period)
- Hight blood pressure now accompanied by one or more other features such as protein in the urine, liver/kidney dysfunction or neurological indicators.
Pre-eclampsia is often symptomless, which can make it hard to diagnose initially and monitor progression. Symptoms, when they do occur, tend to indicate severity and should not be disregarded.
If you have high blood pressure in your pregnancy, your healthcare provider should be regularly assessing your blood pressure and managing appropriately as well as checking your blood for signs of pre-eclampsia.
They will monitor for:
- Proteinuria (protein detected in your urine, a sign of kidney filtration abnormality)
- Visual disturbances, specifically, starry vision
- Severe frontal headaches
- Excessive oedema (swelling) of the hands, legs and face
- Abnormal liver function tests
- Low platelet levels
Pre-eclampsia before 20 weeks is uncommon so the frequency of antenatal visits and checks becomes more frequent in the second semester.
Why does it happen?
While the exact mechanism and cause of pre-eclampsia is still unclear, evidence suggests pre-eclampsia is related to inadequate blood supply to/from the placenta. This results in a hypoxic environment which causes damage to the vascular system leading to high blood pressure and multi-organ injury.
Some of the major risk factors (based on research from 3 systematic studies)
- Chronic hypertension
- First time mothers
- Gestational diabetes
- Chronic kidney disease
- Previous stillbirth
- Maternal age >40yrs
- Pre-pregnancy BMI >30
- Twin pregnancy
- History of IUGR (intra-uterine growth restriction)
- Previous placental abruption
- >5 years between pregnancies
Treatment/management of pre-eclampsia
- Once pre-eclampsia is diagnosed, there is no ‘cure’ - other than to expediate delivery (when safe/necessary) as pre-eclampsia usually resolves following delivery of the placenta.
- High blood pressure can and should be managed by your healthcare provider to prevent vascular emergency. This can be treated by anti-hypertensive medications and regular blood pressure monitoring.
- Facilitation of labour should be considered where possible and timing of delivery optimal to ensure safety of mother and baby.
- Preterm delivery may be required in instances of severe pre-eclampsia as the consequences of disease progression often outweigh the risks of preterm birth.
- Women who are considered high risk may be commenced on low-dose aspirin and in some cases, calcium, in their pregnancy to help prevent pre-eclampsia.
Ongoing implications of Pre-eclampsia
- Babies born from mothers with Pre-eclampsia are at an increased risk for growth restriction, or being small for gestational age at birth
- Mothers are at two-fold increase in cardiovascular risk and death.
- Mothers are at three-fold increased risk for ongoing high blood pressure
- Changes to the liver, adrenal glands, heart and brain due to decreased organ perfusion
- Interestingly (and likely the only benefit) is decreased chances of developing breast cancer in mothers who have had pre-eclampsia in the past, particularly if the baby in that pregnancy was a male.
Written by Keryn Thompson RM & IBCLC (L-301766)
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Cover image by Lucas Mendes