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Pre-eclampsia
Pre-eclampsia
Other names	Preeclampsia toxaemia (PET)
	A micrograph showing hypertrophic decidual vasculopathy, a finding seen in gestational hypertension and pre-eclampsia. H&E stain.
Medical specialty	Obstetrics
Symptoms	High blood pressure, protein in the urine
Complications	Red blood cell breakdown, low blood platelet count, impaired liver function, kidney problems, swelling, shortness of breath due to fluid in the lungs, eclampsia
Usual onset	After 20 weeks of pregnancy
Risk factors	Obesity, prior hypertension, older age, diabetes mellitus
Diagnostic method	BP > 140 mmHg systolic or 90 mmHg diastolic at two separate times
Prevention	Aspirin, calcium supplementation, treatment of prior hypertension
Treatment	Delivery, medications
Medication	Labetalol, methyldopa, magnesium sulfate
Frequency	2–8% of pregnancies
Deaths	46,900 hypertensive disorders in pregnancy (2015)

Pre-eclampsia (PE) is a disorder of pregnancy caused by the onset of high blood pressure. In it, there is a large amount of proteinuria,^[1]^[2] which means protein in the urine.

Usually PE happens during the second half of pregnancy (from 20 weeks) or soon after delivery.^[3]^[5] It can develop for the first time in the first 4 weeks after birth.

They are usually picked up as signs and symptoms in routine tests.^[5] Sometimes the patient is unaware of the symptoms themselves when its diagnosed.

Cause

Risk^[5]

Factors have been identified that could increase chances of developing pre-eclampsia. Having previously had it is a risk factor. Genetics and being the first time delivering increases the chance by a small amount. Having an existing medical problem increases it by more. These medical problems are:

If a pregnant woman is considered to be at a high risk of developing pre-eclampsia, they might be advised to take a 75 to 150mg dose of aspirin every day from 12 weeks pregnant until delivery. Evidence suggests this can lower the chances of developing the condition.^[5]

Other factors increasing the risk, but by a small amount:

over the age of 40
it has been at least 10 years since the last pregnancy
a family history of the condition – for example, the mother or sister has had pre-eclampsia
obese at the start of pregnancy – meaning they had a body mass index (BMI) of 35 or more
if expecting twins or more, such as twins or triplets

Placenta

Pre-eclampsia is thought to be caused by the placenta not developing properly due to a problem with the blood vessels supplying it. The exact cause isn't fully understood.^[5] It may be likely that inherited changes in the genes have some sort of role, as the condition often runs in families. But this only explains some cases if it is true.^[5]

Signals or substances (hormones^{[verification needed]}) from the damaged placenta affect the mother's blood vessels, causing hypertension.^[5] At the same time, problems in the kidneys may cause important proteins that should remain in the mother's blood to leak into her urine, resulting in proteinuria.^[5]

The problem with the placenta means the blood supply between mother and baby is disrupted.^[5]

Early stages of pregnancy

If the placenta will not develop properly because it does not get enough nutrients, it can cause issues. This may lead to pre-eclampsia.^[5]

It's still unclear why the blood vessels don't transform as they should. The same as with earlier causes, pre-eclampsia can be caused by genetic factors. But this only explains one cause if it is true.^[5]

Symptoms

Baby

The main sign of pre-eclampsia in the unborn baby is slow growth. This is caused by poor blood supply through the placenta to the baby.^[5]

The growing baby receives less oxygen and fewer nutrients than it should, which can affect development. This is called intra-uterine or foetal growth restriction.^[5]

If the baby is growing more slowly than usual, this will normally be picked up during antenatal appointments It will be picked up during measurements.^[5]

Mother

Most people only experience mild symptoms, but it's important to manage the condition in case severe symptoms or complications develop.^[5]

Symptom severity

Severe case

Although many cases are mild, the condition can lead to serious complications for both mother and baby if it is not monitored and treated. Symptoms may be:^[5]

red blood cell breakdown
a low blood platelet count
not as good liver function
kidney dysfunction
swelling^[5]
shortness of breath, due to fluid in the lung
visual disturbances.^[4]^[5] (blurring or flashing lights)^[5]

If left untreated, it may result in seizures.

Early signs^[5]

Of pre-eclampsia include having high blood pressure (hypertension), proteinuria. In some cases, further symptoms can develop into the severe symptoms above, but also including:^[5]

severe headache
pain just below the ribs
vomiting
sudden swelling of the face, hands or feet

The earlier pre-eclampsia is diagnosed and monitored, the better the outlook for mother and baby. Symptoms of pre-eclampsia should mean: seek medical advice immediately by calling the midwife, GP surgery or emergency services (EMS).^[5]

Diagnosis

Pre-eclampsia is easily diagnosed during the routine checks that happen throughout pregnancy. Signs of high blood pressure are regular, and a urine sample is tested to see if it contains protein, during antenatal appointments.^[5]

However, if any of the symptoms of pre-eclampsia between antenatal appointments show, a midwife or GP should be seen for advice.^[5]

Tests: blood pressure, blood and urine test, other

Blood pressure checked with an inflatable cuff and a scale as a pressure gauge (a sphygmomanometer) regularly^[5]
Urine sample. This can easily be tested for protein using a dipstick, usually at every appointment^[5]
Blood test may be checked between 20 weeks and 36 weeks and 6 days pregnant.^[5] It measures levels of a protein called placental growth factor (PIGF)