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Causes of low Blood pressure during pregnancy

Published by B+ve

Some of the physiological changes experienced during pregnancy is increased blood volume, relaxation of blood vessels, hemodilution, increased cardiac output, increased pulse rate and decrease in systolic and diastolic blood pressure, due to lower resistance in the peripheral arteries.

In a pregnant woman, there is an increased fow of blood in the body for proper supply of oxygen and food nutrients for it to reach the foetus. As a result of this, the body’s blood pressure decreases which becomes a major cause of low blood pressure or hypotension in a majority of pregnant women. However, other causes include having twins, a medical history of hypotension or other underlying medical illnesses.

During the frst and second trimester, blood pressure falls by 10-15 mm of hg. Decrease in peripheral resistance, to increase the circulation through the placenta is the explanation of low blood pressure. During the second trimester, placental circulation doubles, its arteries expand in size and number leading to hypotension.

A pregnant uterus of more than 20 weeks size falls on inferior vena cava in a supine position and decreases the preload to the heart, further decreasing the blood pressure leading to symptoms of hypotension that is dizziness, syncope and nausea. Blood pressure rises again in the third trimester.

Low blood sugar levels can also present as hypotension. During early pregnancy excess of estrogen and progesterone hormones can also give rise to lethargy, fatigue and shortness of breath. Hypotension can also be caused by blood loss for reasons such as threatened abortion, ectopic pregnancy and abruption placentae. Excessive dehydration due to vomiting can also be a reason of hypotension. Prolonged sitting or standing too can decrease venous return to the heart leading to syncope and hypotension.

Steps to ease the symptoms of hypotension

  • Lie on your left side as it increases the fow of blood to your heart
  • Avoid sudden movement, particularly when standing up from a seated position
  • Avoid standing for a long time
  • Consume several small meals during the day, instead of larger meals
  • Exercise regularly to keep the blood pressure normal
  • Drink plenty of fuids