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Preeclampsia is a condition unique to human pregnancy. It is a disorder which usually develops in the second half of gestation and occurs in around 5-8% of all pregnancies. Preeclampsia can also develop early in pregnancy if it is severe or may not become an issue until during labour or just after the baby has been born.
Preeclampsia is more common in women who are having their first baby. Some studies cite it occurring in up to as much as 10% of pregnancies, but whatever the statistics, it is the most common serious medical problem of pregnancy. It is important for all pregnant women to be checked during ante-natal appointments for any symptoms which could indicate them having preeclampsia. Without treatment, it can sometimes develop into eclampsia which has the potential to cause significant complications for both a mother and her baby.
In cases where the preeclampsia is only mild, there are usually no ill effects on either the mother or her baby. But if the blood flow through the placenta has been reduced and its function affected, the baby’s growth may potentially be impacted and the baby will not be as big or weigh as much as if preeclampsia was not present. A reduction in the oxygen and nutrients the baby receives can compromise its overall growth; this is known as Intra Uterine Growth Restriction (IUGR).
If the mother’s preeclampsia is severe, there is a risk of placental abruption, where the placenta shears away from the uterine wall. Premature delivery and even foetal death can occur in cases where the blood pressure becomes dangerously high.
Timing is the critical issue with preeclampsia. Balancing the baby’s growth and readiness for delivery, whilst not compromising the mother’s health is the major issue. The risk of death to a baby from maternal preeclampsia is not so much from the disorder itself, but because of prematurity complications.
It is not clearly understood why preeclampsia occurs in some women and not in others. Although the risk factors are fairly consistent, they are not prescriptive. It seems there may be an issue with a mother’s inflammatory response where her body’s immune system reacts to the presence of her baby and the placenta.
The only treatment for this condition is delivery of the baby. If the woman’s blood pressure becomes so high that there is a risk to her own health or her baby’s, delivery by caesarean section is usually attended. If the baby is going to be premature, steroid medication to assist with the baby’s lung maturity is given to the mother. Occasionally treatment with anti-hypertensive medication will buy enough time for the baby to remain in utero for as long as possible.
If the blood pressure is only slightly or moderately elevated, the mother may be prescribed oral anti-hypertensive medication and daily blood pressure monitoring. She may be able to do this herself with a portable blood pressure machine. The main objective of preeclampsia management is to monitor the mother’s blood pressure and the baby’s heart beat. With bed rest and a lowering of physical activity, there is usually a reduction in the blood pressure to within normal limits. Monitoring is also necessary to ensure that preeclampsia is not progressing to eclampsia.
By definition, non-severe hypertension is classified as having a blood pressure reading of 140-159/90-109. Severe hypertension being defined as a top or systolic reading of more than or equal to 160 or a bottom reading of more than or equal to 110.
Occasionally, preeclampsia escalates to a dangerous level. This can occur in a relatively short period of time and although it is uncommon its effects are so significant that it is worthwhile being aware of them. Seek medical assessment if you develop any of the following signs or symptoms:
Monitoring of a mother’s blood pressure continues in the early hours after delivery. If her blood pressure has been very high, medication is given and then prescribed routinely to keep it within normal limits. Regular monitoring is important. In the majority of cases, a mother’s blood pressure returns to a normal range once her baby is delivered.
There has been some evidence to support the findings that women who have had preeclampsia during their pregnancy are at a greater risk of cardiovascular disease later in life. Maintaining a healthy weight and lifestyle throughout life helps to reduce the likelihood of long term problems.
At present there are no real prevention strategies which are thought to be effective. In some women a daily dose of aspirin when taken from around the 14th week of pregnancy is thought to be preventative. But this would only have a positive effect on a small number of women and it is difficult to select which ones this would be.
There is also some evidence to support the idea that an addition of calcium supplements in a mother’s diet may be useful in preventing preeclampsia.