Your Blood Pressure
It's normal for your blood pressure to change a little during pregnancy. It often decreases a little during the second trimester of pregnancy and increases toward the end of pregnancy.
If you have high blood pressure, resting in bed on your side can help. If your blood pressure is still too high, you may need medications to lower it.
Low Blood Pressure
There are two causes of hypotension (low blood pressure) in pregnancy. It can be caused by the enlarging uterus putting pressure on large blood vessels, such as your aorta and vena cava. This is called supine hypotension and may happen when you lie down. It can be alleviated or prevented by not sleeping or lying on your back.
The second cause is called postural hypotension. When you rise rapidly from a sitting, kneeling or squatting position, gravity causes blood to leave your brain. This may result in a drop in blood pressure. Avoid postural hypotension by getting up slowly from a sitting or lying position.
Blood-sugar problems can cause dizziness. High blood sugar (hyperglycemia) or low blood sugar (hypoglycemia) can make you feel dizzy or faint. Many doctors routinely test pregnant women during their pregnancies for problems with blood sugar.
If you have a problem with blood sugar, eat a balanced diet, don't skip meals and don't go a long time without eating. Many do better with eating 4 or 5 smaller meals a day, rather than 3 larger meals. If the condition is more serious, you may need to see a dietitian.
Pregnancy-Induced High Blood Pressure
Pregnancy-induced hypertension is high blood pressure that occurs only during pregnancy. It disappears after the baby is born. It develops in about 3% of women under age 40, and in 10% of women over 40.
This condition is treated by resting in bed on your side, by drinking lots of fluid and by avoiding salt and foods containing large amounts of sodium. Medications to lower blood pressure may be prescribed.