(Tuesday, 31st Mar, 2015)
High blood pressure (hypertension) in pregnancy
Hypertension is the medical term used to describe high blood pressure. Regular monitoring of blood pressure levels is a very important element of modern antenatal care.
While the Irish medical profession place great emphasis on blood pressure readings in pregnancy, many women remain confused about what actually constitutes high blood pressure.
The normal blood pressure reading in a healthy woman of 25 is 120/70mm of mercury. The upper figure (120) is called the systolic blood pressure while the lower figure which is, by far, the more important of the two readings is the diastolic blood pressure.
The upper figure, or systolic blood pressure, varies with emotion and exercise, but changes in the lower figure, or diastolic reading, indicate a fundamental alteration in the body.
In a normal pregnancy, the average reading of 120/70 should not alter greatly, although it may be reduced in mid-pregnancy.
If a woman has raised blood pressure before pregnancy, she will need to be specially carefully monitored throughout her pregnancy.
One of the most important reasons for regular monitoring of blood pressure throughout pregnancy is to detect the early signs of the pre-eclampsia, a condition which can have very serious consequences for both mother and baby if it is untreated.
Pre-eclampsia is a condition which is specific to pregnancy and, if undetected, it can lead to a much more serious, and potentially fatal, form of the disease known as eclampsia.
Pre-eclampsia is diagnosed when a woman develops high blood pressure (hypertension), accumulation of fluid in the tissues (oedema) and protein in the urine (proteinuria). It is extremely rare before 20 weeks and is more likely in a first pregnancy than subsequent pregnancies. An affected woman may also complain of headache, nausea, vomiting, abdominal pain or visual disturbances.
If pre-eclampsia is untreated it may lead to eclampsia, which is characterised by seizures, and may be fatal to both mother and baby.
For mild cases of pre-eclampsia, bed rest and frequent monitoring may be sufficient. Bed rest increases the blood flow to the placenta and, as a result, the nutrition to the developing baby is improved.
If the condition continues to worsen (a persistent blood pressure reading greater than 140/90 usually), a woman may be admitted to hospital for management, including anti-hypertensive drugs (drugs to reduce blood pressure) and intensive monitoring of both mother and baby.
If the increased blood pressure persists close to term or eclampsia is imminent, induction of labour or a caesarean section may be necessary.
Eclampsia is a condition characterized by seizures, which is unique to pregnancy. It develops in women with untreated or uncontrollable pre-eclampsia. The very best treatment for eclampsia is its prevention as, even with the very best of medical care, it can result in the death of both mother and baby.
Thankfully, eclampsia is a very rare condition in Ireland today, but the importance of regular antenatal check-ups, where blood pressure readings will be monitored, cannot be stressed enough.
There appears to be links between high blood pressure and being overweight, although there are many cases of underweight people with high blood pressure as well.
The advice to any woman contemplating pregnancy, especially if she is overweight and suffers from high blood pressure, is to lose weight before becoming pregnant.
Salt is another contributory factor in high blood pressure, so cutting down on salt, or cutting it out of the diet altogether, is also a good idea.
Antenatal care in Ireland is among the best in the world, so the most important piece of advice for any woman who wants to avoid the many serious problems associated with high blood pressure in pregnancy is to attend all her antenatal appointments.
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