OVERVIEW

Pregnancy for most women seems to be a very exciting, thrilling and captivating period. However this same beautiful dream phase of every woman’s life could become predicated by the occurrence of certain medical conditions that increases the morbidity and mortality for the mother and baby making the whole pregnancy period dreadful.

An example of such condition is pre-eclampsia. It complicates about 2%-7% of pregnancies with about 50,000 women dying annually. This is usually more common in primigravid (a woman who is pregnant for the first time) than multiparous women (a woman given birth to more than one child)

Pre-eclampsia is classified as an example of hypertensive disorders during pregnancy. Hypertension means an above optimum pressure with which the blood flows through the arteries such that it has detrimental effects on the body.

Putting numbers on it, hypertension is when an individual records on 2 or more consecutive occasions, blood pressures of greater than or equal to 140 and or 90 (systolic / diastolic). If this occurs after the 20th week of pregnancy, it is called gestational hypertension, and if it happens before the 20th week of pregnancy and persists for more than 6 weeks after delivery, it is called chronic hypertension.

DEFINITION 

Pre-eclampsia is when a woman becomes hypertensive after 20weeks of pregnancy with associated end organ damage as a result of the release of inflammatory mediators due to defunctive perfusion of blood between the uterus and placenta.

Most common evidence of end organ involvement is seeing proteins in the urine (proteinuria). Hence conventionally the definition of preeclampsia is the presence of hypertension and proteinuria in a previously normotensive non proteinuric woman after 20weeks of pregnancy. If a woman has chronic hypertension and begins to develop proteinuria in pregnancy it is called chronic hypertension superimposed with pre eclampsia.

So how does a woman having a raised blood pressure and proteinuria affect her and the baby?

● It causes damage to the blood vessels supplying all the organs of the body. Think of the blood going into the woman’s brain, heart, lungs, liver, and kidneys in a vessel. Once there is vessel damage or dysfunction, these paramount body parts are deficient of optimum blood supply causing them to begin to dysfunction as their cells and tissues undergo ischemia.

The kidneys lose their ability to prevent the loss of blood proteins into the urine.
When the woman loses blood proteins through the urine coupled with damage to
the endothelium of the vessels, it causes the fluid portion of the blood (plasma) to now move into the surrounding tissues and cavities in the body presenting as edema (swelling of the body).

Think of this edema; if fluid now builds up in the brain it puts pressure on the brain, the brain begins to malfunction and the woman could end up having vomiting, double vision and abnormal brain activity manifested as a seizure. She can then be tipped into a coma and stands a high chance of losing her life.

This same damage to the blood vessels leads to inflammatory processes occurring in the liver, causing damage to the cells and tissues of the liver and accumulation of fluid in the liver’s interstitial space.

This accumulation causes stretching of the outermost capsule of the liver causing severe pain in the right upper quadrant – mostly the epigastric region.
This same phenomenon will lead to malfunctioning of the heart , lungs and other organs of the body.

● The baby receives nourishment from the mother via the placenta which is the bedrock of this condition. If the vessels supplying the baby is defunct, the baby doesn’t receive enough nourishment, it then goes through growth restriction (small for gestational age) whiles in utero and eventually will die.

What brings about pre-eclampsia?
(PATHOGENESIS) 

The exact cause of preeclampsia is not known. However experts believe it begins in the placenta and spread to other parts. From the 20th week of pregnancy, the vessels (spiral arterioles) in the placenta are expected to dilate and have low resistance of vasoconstrictive factors to allow more exchange between the uterus and placenta.

However, due to certain factors, the spiral arteries fail to do so and this causes ischemia of certain placental parts thereby causing the release of inflammatory chemicals into the mother’s general blood circulation. These inflammatory mediators begin to damage the mother’s blood vessels causing them to constrict (become narrower) as well as become leaky.

The narrower they become the higher the blood pressure will be because now the heart has to pump blood at a higher pressure through narrowed vessels. Furthermore, as already explained above, the high pressure affects other organs like the kidneys causing their dysfunction leading to proteinuria and its sequelae.

The kidneys also have a huge role to play in further increasing blood pressure via the renin angiotensin aldosterone system triggered by decreased blood flow into the kidneys due to the narrowing; this further worsens the woman’s condition.

Risk factors

As we don’t know the exact causes of pre-eclampsia, it’s difficult to predict who will develop it or not.

However, you are considered at greater risk if you fall into the following risk factors. It is important to note that, not all pregnant women with the following condition will present with pre-eclampsia.

● first pregnancy
● extreme of age especially maternal age > 40yrs
● previous history of hypertensive disorder in pregnancy
● increased maternal age
● obesity
● diabetes
● hyperlipidemia
● multiple gestations (twins, triplets, etc.)
● pre-existing hypertension
● family history of hypertension
● use of illicit drugs
● smoking.
● In vitro fertilization.

Symptoms 

Symptoms depends on how severe the condition is. There are two categories of pre-eclampsia; mild pre-eclampsia and severe pre-eclampsia. In mild pre-eclampsia, the blood pressure is ≥ 140/90 while in severe pre-eclampsia, the blood pressure is ≥ 160/110 with severe symptoms

Some pregnant women with the mild form may have no symptoms. The following symptoms are usually in the severe form though they can also be seen in some cases of mild pre-eclampsia.

● Persistent headache
● Cerebral or visual disturbance
● blurred vision
● flashes of light
● nausea and/ or vomiting
● difficulty in breathing
● Abdominal pain (usually in the epigastric region and right upper quadrant of the abdomen)
● oliguria (urine output <500mls/24hrs)
● Sudden weight gain and swelling (edema): typically in your face and hands.

In sub-Saharan Africa, because of the increasing influence in western diet and lifestyle, most adults seem to develop hypertension quite early. Another contributing factor, work-related stress has predisposed most adults to hypertension development.

In adolescents, secondary hypertension is prominent due to the chronic use of drugs and alcohol. These cause kidney disorders which predispose such groups to hypertension.

Investigations

Usually the standard investigation to establish pre eclampsia is blood pressure measurement. Subsequently other test such as blood and urine analysis are done to complement the diagnosis and ascertain the severity.

Blood sample is usually taken for
● full blood count
● blood film comment
● urea and creatinine
● electrolytes
● uric acid
● liver function tests
urine sample is also taken for
● urine dipstick to measure the protein in urine.

Complications

If preeclampsia is not treated quickly and properly, it can lead to serious complications for both the mother and the baby.

Maternal complications

● Eclampsia (fits); preeclampsia plus seizures
● HELLP syndrome; hemolysis, elevated liver enzymes, and low platelet count- This is a syndrome which usually occur late in pregnancy that affects the breakdown of red blood cells, blood clotting, and liver function.
● placenta abruption; a condition in which the placenta separates from the normal inner wall of the uterus before delivery
● disseminated intravascular coagulopathy(DIC); blood clotting disorder
● Stroke
● retinal damage which can lead to loss of vision
● kidney failure
● pulmonary edema
● pulmonary infarction
● hepatic failure

Fetal complications

● fetal growth restriction; Babies of some women with pre-eclampsia may grow more slowly in the womb than normal because pre-eclampsia reduces the amount of nutrients and oxygen that gets to the baby.
● intrauterine fetal death; Some babies of women with pre-eclampsia may die in the womb before delivery
● Premature delivery
● early neonatal death as a result of prematurity

Prevention 

1. Modifiable risk factors: rest, exercise, avoiding sedentary lifestyles , reduce salt intake .
2. Prophylactic Drugs: Low dose aspirin and calcium supplements has been studied and known to have good effects in terms of reducing the risks of developing pre eclampsia.
3. Treating and control of pre-existing medical conditions before pregnancy e.g hypertension, diabetes, obesity, etc.
4. Early antenatal care visit. This allows women to be properly screened so that those who are at a high risk would have close monitoring of the condition.

Management 

The definitive treatment for pre-eclampsia is the delivery of the baby and placenta. Usually, the decision to deliver depends on the severity of the disease and the viability of the fetus.

In mild pre-eclampsia, expectant management is advisable provided the baby is not term (37 complete weeks).

Expectant management include: bed rest, close monitoring of the mother and fetus, using antihypertensive to control the high blood pressure
In severe pre-eclampsia, the following should be done;

● Control and monitoring of blood pressure using antihypertensive medications such as calcium nefidipine, labetalol, hydralazine and methyl dopa.
● Prevent eclampsia with magnesium sulphate
● Deliver the fetus and placenta as soon as practicable. This can be done either vaginally or via cesarean section. However the babies are delivered premature and require neonatal intensive care.

Conclusion

Pre eclampsia is a very common obstetric condition that has serious maternal and fetal effect. It is not entirely preventable but can be managed if diagnosed early. Once you’re pregnant, take care of yourself and your baby by seeking prenatal care.

Dr. Samuel Adu Agyen