Low blood pressure in pregnancy: values, symptoms and risks

Low blood pressure during pregnancy often results from the fact that during this time your body secretes hormones, and especially progesterone, that help relax blood vessel walls and increase blood flow to you and your baby. Many pregnant women suffer from low blood pressure and this is usually not a problem: it is generally a condition that does not require pharmacological interventions and which disappears during the third trimester. Your doctor will monitor your blood pressure throughout your pregnancy. Only rarely can it be indicative of some other problem (such as an ectopic pregnancy, which is a pregnancy in which a fertilized egg is implanted outside the uterus) and only if it is very low can it cause falls or damage to organs, a process called shock.

Blood pressure during pregnancy

Blood pressure is the force with which the heart pushes blood through the blood vessels.

It is quite common that during their pregnancy women have low blood pressure due to the countless changes their body undergoes during this period.

In the first two trimesters of pregnancy, blood pressure physiologically tends to drop, especially the minimum, until the 20-24th week, or in the middle of the second trimester.

However, low blood pressure cannot be considered a symptom of an ongoing pregnancy, even more so due to the fact that in the first phase of the first trimester,  low blood pressure is often asymptomatic.

Pressure readings in pregnancy

The value of systolic blood pressure (the “maximum”) is linked to the maximum blood flow expelled at each systolic phase, i.e. at each phase of contraction of the heart muscle.

The value of diastolic blood pressure (the “minimum”) is linked to the rest period of the heart, i.e. to the diastole phase.

In a healthy individual, the systolic blood pressure value (the one corresponding to the highest number) at rest should be around 120 mmHg, while the diastolic value (corresponding to the lowest number) should be around 80 mmHg. You are hypertensive when you are above 140 mmHg of maximum pressure, or you are above 90 mmHg of minimum pressure, while your blood pressure is considered low when you are below the normal level by at least one of these two values.

Compared to normal reference values ​​– i.e. compared to a systolic blood pressure around 120 mm Hg, and a diastolic blood pressure around 80 mm Hg. – in most pregnant women, systolic blood pressure drops by 5-10 mmHg, while diastolic blood pressure drops by about 10-15 mmHg.

Some people have lifelong low blood pressure, and show no signs of it. However, results from blood pressure measurements can vary depending on a person’s general health and medical history.

The cause

The woman’s body produces hormones, in particular progesterone which helps to relax the walls of the vessels, and this will probably cause them to drop in pressure during the first and second trimester of pregnancy.

However, as the third trimester approaches, blood pressure will begin to rise again, and should return to normal levels within a few weeks after delivery. 

The above is the most common cause of hypotension in pregnancy. The other possible causes may arise :

  • from dehydration,
  • from anemia,
  • from internal bleeding,
  • from taking certain medicines,
  • from heart disease,
  • from endocrine disorders,
  • of infections,
  • from nutritional deficiencies,
  • from allergic reactions.

Epidural anesthesia often leads to a sudden drop in blood pressure during labor. 

Symptoms of low blood pressure in pregnancy

Low blood pressure in pregnancy can cause the following symptoms

  • confusion
  • dizziness
  • weakness
  • fatigue
  • blurry vision
  • nausea
  • vomit
  • daze
  • cold, clammy, or pale skin

But low blood pressure can lead to serious symptoms, like fainting.

In any case, even the slightest symptoms should not be underestimated as they can lead to falls, with consequent risks for both the mother and the fetus. For this reason, even if only in the presence of confusion, dizziness, lightheadedness or weakness, it is advisable to talk to your doctor in order to find a remedy.

Common causes of low blood pressure other than pregnancy

Aside from pregnancy, other common causes of low blood pressure are as follows:

  • alcohol intake
  • taking anxiolytic drugs, antidepressants, painkillers, diuretics
  • diabetes
  • irregular heartbeat
  • heart failure
  • dehydration 

Prevention and natural remedies

Before taking medicines, it is possible to try both to prevent and to counteract low blood pressure by resorting to adequate nutrition. In particular,

  • taking a fair amount of salt through the normal diet (however the intake of an excessive amount of salt could affect the fetus or lead to too high blood pressure), 
  • drinking plenty of fluids, 
  • following a balanced diet,
  • taking daily the necessary vitamins, and all folic acid supplements.

His diagnosis

The existence of low blood pressure is detected using a fairly simple instrument: the sphygmomanometer.

To measure blood pressure, in a hospital, clinic or any outpatient clinic, a doctor or nurse will place a band around the arm, inflate it, and in a few seconds will detect the minimum and maximum value.

However, the detection is also feasible from your own home, using a blood pressure monitor that can be purchased in pharmacies, parapharmacies and even online for a few tens of euros.

Low pressure treatments

In general, special treatments are not necessary to counteract the lowering of blood pressure that occurs during pregnancy.

Doctors do not recommend that pregnant women take any medicines unless their symptoms are particularly severe and complications may occur.

The woman’s blood pressure will likely return to normal during the third trimester of pregnancy.

Helpful tips to manage symptoms

Here are some useful tips to increase blood pressure values, and to avoid/limit the onset of symptoms. The woman who is in the period of gestation should,

  • lie on your left side in order to increase blood flow to the heart, 
  • avoid getting up suddenly,
  • do not stand for prolonged periods,
  • eating frequent meals throughout the day
  • avoid taking excessively hot showers or baths,
  • stay hydrated;
  • wear clothes that are comfortable.

However, to prevent the symptoms of low blood pressure it is always good to follow a healthy diet and take the food supplements recommended by your doctor for pregnancy. Your doctor may also recommend increasing your salt intake.

Low blood pressure in pregnancy: when to worry

The pregnant woman must pay attention to those symptoms associated with low blood pressure that we indicate because they could indicate the existence of serious problems:

  • a feeling of faintness that gets worse
  • a severe headache ,
  • vision problems, 
  • excessive vomiting,
  • shortness of breath,
  • an extremely fast heartbeat,
  • a pain in the chest,
  • a bleeding,
  • a tingling sensation in one side of the body.

Extremely low blood pressure could – in particular – increase the risk of damage to maternal organs. In some rare cases, it could be associated with complications, such as ectopic pregnancy. 

Any problems for the unborn child

Much research has been done, both on the origin of low blood pressure during pregnancy and on how it could affect the fetus. However, the available results are limited.

Some studies have hypothesized that low blood pressure during pregnancy leads to certain problems, such as stillbirth, and low baby weight. However, these studies cannot be considered conclusive, and further research is needed to fully understand the impact of low blood pressure in pregnancy on the health of the baby. 

In the vast majority of cases, low blood pressure is nothing to worry about.


Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform, Maternicity.com.

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