What Causes Low Blood Pressure in Pregnant Women?

It is widely known that hypertension during pregnancy is extremely dangerous; however, hypotension must not be overlooked. Although hypotension has no obvious direct impact on the fetus, if left untreated, its associated risks may escalate. Pregnant women often experience symptoms such as dizziness, loss of appetite, and low mood—conditions that significantly compromise maternal health and, indirectly, fetal development. So, what causes hypotension in pregnant women?

Causes of Hypotension in Pregnancy

As gestational age advances, fetal growth accelerates. Concurrently, the uterus expands rapidly, compressing veins and impeding venous return, thereby reducing cardiac output—and consequently lowering blood pressure. In late pregnancy, reduced venous return to the heart—due to various physiological factors—further contributes to decreased blood pressure. Genetics: Some cases of pregnancy-related hypotension may have a hereditary component. Mild cases may present without noticeable symptoms, whereas more severe cases can manifest with dizziness, headache, fatigue, or even syncope—requiring timely medical intervention.

Deficiency of Qi and Blood: Women with inherently weak constitutions or inadequate nutritional intake during pregnancy are prone to hypotension due to qi and blood deficiency. Thus, expectant mothers should enhance their dietary nutrition by consuming iron- and blood-enriching foods—such as donkey-hide gelatin (ejiao), red dates, pork liver, chicken, beef, egg yolks, pig blood, and lean meat. Additionally, sudden postural changes during pregnancy can trigger hypotension. Uterine enlargement may compress the aorta and inferior vena cava; therefore, lying supine may induce hypotension, whereas sleeping on the side can reduce or prevent this effect. Similarly, abruptly rising from sitting, kneeling, or squatting positions may cause an acute drop in blood pressure, resulting in dizziness.

When experiencing hypotension, pregnant women should consume nutrient-dense foods rich in cholesterol and sodium—such as brain tissue, liver, and nuts—to help elevate blood pressure moderately. Regular, appropriate physical activity tailored for pregnancy is also recommended. Moreover, women with recurrent hypotension should consult a healthcare provider to identify the underlying cause and receive targeted treatment. We hope this information proves helpful.