Low blood pressure during pregnancy is not uncommon, especially during the first and second trimesters. Doctor Than Thi Quynh Hoa, from the Obstetrics and Gynecology Center at Tam Anh General Hospital in Hanoi, explains that during the first half of pregnancy, increased progesterone levels cause blood vessels to dilate, increasing blood volume to the uterus and placenta, resulting in slower blood circulation and a slight drop in blood pressure. The increased blood flow required to nourish the fetus also makes the heart and circulatory system work harder. This can lead to uneven blood distribution throughout the body, causing insufficient blood flow to the brain and other organs.

Several other factors can contribute to low blood pressure, such as sudden changes in posture from sitting to lying down or vice versa, dehydration, poor nutrition with insufficient iron, vitamin B12, or folic acid, and inadequate rest or prolonged sleep deprivation. The symptoms of low blood pressure during pregnancy can be subtle and easily mistaken for common pregnancy symptoms. Here are some of the most frequent symptoms.

Dizziness and lightheadedness are typical signs of a sudden drop in blood pressure, which reduces blood supply to the brain. Pregnant women may experience blurred vision, vertigo, or loss of balance when changing positions abruptly. In many cases, the dizziness forces them to sit or lie down to avoid falling.

Fatigue and exhaustion can occur due to inadequate blood supply to the organs. This can leave pregnant women feeling drained and struggling with daily activities.

A rapid heartbeat and shallow breathing occur as the body reacts to low blood pressure. The heart rate increases to compensate for the reduced blood flow.

Headaches and blurred vision result from decreased blood flow to the brain due to low blood pressure.

Cold, pale skin, especially in the extremities like hands and feet, is caused by weakened peripheral circulation.

Nausea can be easily mistaken for morning sickness. However, if accompanied by cold sweats, anxiety, shortness of breath, dizziness, and pale skin, it could indicate low blood pressure. This type of nausea often occurs when a pregnant woman is hungry, sleep-deprived, or after a sudden change in posture.

Sudden fainting usually happens in cases of severe low blood pressure when there isn't enough blood reaching the brain. This is a dangerous warning sign that can lead to falls, injuries, and potential harm to the fetus.

A doctor at the Obstetrics and Gynecology Center consults with a pregnant woman. Illustrative photo: Provided by the hospital

According to Dr. Hoa, normal blood pressure in pregnant women is around 90-120 mmHg (systolic) and 60-80 mmHg (diastolic). In most cases, mild low blood pressure doesn't seriously affect the fetus. However, if blood pressure frequently drops below 90/60 mmHg, especially below 80/50 mmHg, close monitoring is necessary as it can reduce blood flow to the fetus, leading to oxygen and nutrient deficiency. This can affect fetal development and cause complications like fetal distress, stillbirth, premature birth, and intrauterine growth restriction. The mother may also experience reduced blood flow to the brain, increasing the risk of fainting and falls.

If experiencing signs of low blood pressure, Dr. Hoa advises pregnant women to take prompt action to stabilize their condition. Immediate first-aid steps include lying on the left side to improve blood flow to the heart and brain, avoiding pressure on the vena cava. Placing a pillow under the feet and slightly elevating them can help blood return to the heart faster. Drinking enough water, eating a light snack, taking deep breaths, and relaxing can calm the nerves, increase oxygen and blood sugar levels. If feeling weak, unable to move, or at risk of fainting, it is essential to call for help from family or medical professionals.

To minimize the risk of low blood pressure, pregnant women should eat a balanced diet, have frequent small meals, avoid prolonged fasting, prioritize iron-rich foods, protein, B vitamins, and stay hydrated. They should avoid sudden changes in posture and stand up slowly after sitting for a long time. When getting out of bed, they should turn to their side before sitting up. Adequate rest, sufficient sleep, and stress management are also important. Regular blood pressure monitoring is crucial, especially for those with a history of low blood pressure or fainting during previous pregnancies. Light exercise such as walking, prenatal yoga, or swimming can improve blood circulation and blood pressure.

If low blood pressure persists or doesn't improve despite these measures, pregnant women should seek medical attention to rule out underlying medical conditions. Those with a history of low blood pressure due to medical conditions (severe anemia, infections, endocrine disorders, etc.) should follow their doctor's treatment plan.

Trinh Mai