Causes of high blood pressure in women

High blood pressure (hypertension) is a serious condition that may damage blood vessels and vital organs over time. According to the Centre for Disease Control and Prevention (CDC), around 1 in 3 adults in the US have hypertension, putting them at risk for the two leading causes of death – heart disease and stroke.

Recent research published in the Journal of Therapeutic Advances in Cardiovascular Disease suggests that women with high blood pressure are at a higher risk of vascular disease than their male counterparts. Researchers found “significant differences” in the mechanisms that causes high blood pressure in women, compared to men [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5159215/ ]. In this blog, I will be discussing some possible causes of hypertension among women and their associated risk factors.

Menopause

Developing hypertension is said to affect 13% of women under the age of 44. Nearly 50% of women in their 60s and 80% or more of those aged 75 and over. During the menopause your body goes through a number of changes. One of the symptoms that may develop includes hypertension. There is no conclusive link but there are various schools of thought to explain an increase in blood pressure and the onset of the menopause. For decades, estrogen has been thought to protect premenopausal women from heart disease. So when your estrogen levels start to decline, the level of high-density lipoproteins (good cholesterol) decreases, which then leads to the formation of plaque in the blood vessels, which narrows the arteries. This reduces the amount of blood that can get through, diminishing the amount of oxygen that reaches the heart. This then puts you at a greater risk of causing serious damage to your heart.

Due to an assumed link that estrogen lowered low-density lipoproteins (bad cholesterol), menopausal women are encouraged to consider using hormone therapy simply to protect their heart and improve health outcomes. But research conducted among participants between 2002 and 2004 found conflicting results. Women were given combined derivatives of progestin and estrogen. Results showed a slight increase in heart attacks, strokes and breast cancer. Several limitations to the study were found, which could have clouded the results. The progestin used in the study was previously linked to coronary artery spasms, while progesterone relaxes the arteries.

Research would indicate that the estrogen derivative taken alone or combined with a biologically identical progesterone, may have given different results. In other words, effectively increasing high-density lipoproteins (good cholesterol). This has been supported by an article in the Journal of the North American Menopause Society. Studies reviewed, found that post menopausal women who were taking biological identical estrogen and/or progesterone did not have any significant change in blood pressure.

There is another school of thought that links menopause with weight gain. Muscle mass tends to diminish with age, whilst fat increases. Excess body fat puts a strain on your heart, increasing your risk for developing hypertension and damage to your blood vessels. This can then lead to more serious health threats.

Bearing in mind menopause weight gain, it is important that you assess eating habits and your attitude to physical activity. If you continue to eat as you always have done and fail to exercise, then you can expect to continue to gain weight. Reducing body fat is crucial to controlling and preventing high blood pressure. According to a study published, a reduction of 5-10% can have a major impact on your blood pressure [https://jcp.bmj.com/content/56/1/17]

Pregnancy

High blood pressure is affecting more and more pregnant women. According to the Centre for Disease Control and Prevention (CDC), the number of pregnant women who developed hypertension in the United States almost doubled between 1993 and 2014 [ https://www.medicalnewstoday.com/articles/323969.php ]

In some women, blood pressure may also increase as a result of pregnancy, which can be dangerous for both mother and baby. Many babies born to mothers with hypertension are perfectly healthy, but the condition can cause low birth weight and premature delivery. The mother on the other hand, can experience kidney damage and other organ impairment. Close monitoring of hypertension and treatment is therefore very important, because this would help to reduce harm.

Blood pressure normally falls during pregnancy due to the increased production of hormones. These hormones foster fetal growth as well as to sustain and prepare the ‘mother-to-be’ for delivery and breastfeeding. These hormones, particularly progesterone, cause a general relaxing of the walls of your blood vessels.

As you approach the third trimester of the pregnancy, your blood pressure will then start to slowly rise. To coincide with your due date, the blood pressure should reach the level it was prior to pregnancy.

There are three main causation of hypertension during pregnancy:-

  1. Chronic high blood pressure
  2. Pre-eclampsia
  3. Gestational hypertension

Chronic high blood pressure

This is hypertension that was present before pregnancy or that occurs before 20 weeks of pregnancy. This blood pressure may increase during the first trimester and then fall again during the second trimester [to the original level prior to pregnancy].

Research has shown that chronic hypertension is associated with a high incidence of adverse pregnancy outcomes compared with the general population. This research supports the need for increased antenatal surveillance for women with chronic hypertension, in order to enable early identification of evolving complications.

The most recent UK Confidential Inquiry into Maternal and Child Health identified chronic disease as an underlying factor in preventable maternal deaths (reference). The World Health Organization (WHO) recommends that daily calcium supplementation (1.5g – 2.0g orally) is prescribed for pregnant women to reduce the risk of hypertension. This is particularly vital where there is low dietary calcium intake [https://www.who.int/elena/titles/calcium_pregnancy/en/].

Pre-eclampsia

Pre-eclampsia arises only during pregnancy and disappears after the fetus is delivered. It is a combination of high blood pressure, ankle swelling and protein in the urine during the second half of pregnancy. These symptoms are not evident during the early stages of pregnancy and as such, pre-eclampsia can be difficult to diagnose. It is only detectable by regular antenatal checks of maternal blood pressure and urine.

The British Charity Action on Pre-eclampsia (APEC) estimates that:

“Every year in the UK about 1000 babies die because of pre-eclampsia – many of these as a consequence of premature delivery, rather than the disease itself. Some 7 mothers die each year from complications or pre-eclampsia in the UK.” [https://www2.aston.ac.uk/aston-medical-school/amri/an-introduction-to-preeclampsia/index]

The exact cause of pre-eclampsia is not fully understood. Many experts believe that some cases of pre-eclampsia are caused by a shallowly implanted placenta, which becomes deficient in oxygen due to a problem with the blood vessels supplying it. The shallow implantation of the placenta in the lining of the womb, is believed to stem from the woman’s immune reaction. This then triggers a destructive attack on the tissues of the developing fetus, causing her blood pressure and protein levels to rise. The baby is now put at serious risk of harm.

A number of studies have identified a link between genetics and pre-eclampsia. Research has shown there to be an increased risk for women who have family members who have also been diagnosed with this condition [https://www.sciencedaily.com/releases/2012/11/121115132613.htm]. There are also schools of thought that suspect nutritional factors and obesity plays a role in its development. This is as yet, to be fully understood.

The treatment decisions for pre-eclampsia depends upon a number of factors:

  • How severe the condition is;
  • Potential for maternal complications;
  • How far along the pregnancy is;
  • Potential risks to the fetus.

Signs of severe pre-eclampsia include:-

  • Blurry vision, sometimes seeing flashing lights
  • Headaches, often severe
  • Malaise
  • Shortness of breath
  • Pain just below the ribs on the right side
  • Rapid weight gain (caused by fluid retention)
  • Vomitting
  • Decrease in urine output
  • Decrease in blood platelets
  • Impaired liver function

If the pregnancy is 37 weeks or later, then doctors may probably choose to deliver the baby to treat pre-eclampsia and avoid further complications. Less than 37 weeks and doctors may consider treatment options that give the fetus more time to develop. It just depends on the severity of the mother’s condition. They could simply choose to monitor the baby and mother closely. Encouraging bed rest and then wait for delivery.

If you have severe pre-eclampsia at 34 weeks of pregnancy or later, the American College of Obstetricians and Gynecologists recommends delivery as soon as medically possible. If the pregnancy is less than 34 weeks, then the use of corticosteroids could be advised. This will help to speed up the maturation of the fetal lungs before attempting delivery.

There is current research being undertaken in the United States and the United Kingdom, which is looking at whether a drug called ‘Pravastatin’ could be safe and effective to prevent or treat severe or early on-set pre-eclampsia. Studies have been carried out to mimic many of the key characteristics of this condition, and has shown that Pravastatin improves several of the biochemical measures associated with severe pre-eclampsia in women.

This research is still in its infancy, but these exciting results are definitely a move in the right direction [https://www.preeclampsia.org/].

Gestational Hypertension

Gestational hypertension is defined as high blood pressure without swelling or the presence of protein in the urine. This occurs in women who had normal blood pressure before conception. It usually arises in the late stages of pregnancy and then resolves within a few weeks of the delivery. It tends to occur again in future pregnancies.

Gestational hypertension is just as serious a condition as pre-eclampsia and requires the same careful monitoring.

Birth control pills

One very effective birth control method is the combined oral contraceptive pill. It is a combination of synthetic female hormones developed specifically to prevent pregnancy.

Medical researchers have found that the use of birth control pills can increase blood pressure in some women. There are no symptoms with this side effect. It is more likely to occur if you are overweight, have had hypertension during previous pregnancies or a family history of hypertension or mild kidney disease.[https://www.uptodate.com/contents/effect-of-hormonal-contraceptives-and-postmenopausal-hormone-therapy-on-blood-pressure]

Before you start taking oral contraceptives, I would advise that you speak with your doctor about the risks and to ensure close monitoring of your blood pressure.

Polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a condition that affects the way your ovaries work. 6 – 10% of women of reproductive age are diagnosed with this condition (ref). Research has shown that women diagnosed with PCOS have malfunctioning ovaries, which produce an excess amount of the male sex hormone called ‘Androgen’. These hormones are also typically present in women, in very small amounts.

With the presence of large amounts of hydrogen, this will affect your menstrual cycle. The hallmarks of PCOS are therefore menstrual cycle irregularities, excessive hair growth, weight gain, oily skin and acne.

One of the most devastating symptoms is a high risk of heart disease, which is due to hypertension and high cholesterol levels that many women with this condition develop. Despite this link, the exact mechanism responsible for hypertension in these women remains controversial. There is also an additional risk of developing diabetes. The combination of these findings is referred to as ‘metabolic syndrome’. Please follow the link below to learn more about this [https://www.webmd.com/heart-disease/guide/metabolic-syndrome#1].

Research documented in the International Journal of Cardiology 2014 found there to be an increased incidence of cardiovascular events in women with PCOS, but did not distinguish between coronary heart disease and stroke. They also failed to consider fatal and non-fatal events separately.

In any case, this highlights the need for clinicians to prioritize the screening of women with PCOS, as soon as a diagnosis is made. Along with the pharmacological treatments for hypertension, dyslipidaemia (high levels of fat in your blood) or insulin resistance (ref), I would recommend that you explore lifestyle modifications that may also prove effective in reducing your risk of a stroke or other heart complications.

Here are some suggestions that could help to decrease the effects of PCOS:-

  • Maintain a healthy weight – weight loss can reduce insulin and androgen levels and may restore ovulation.
  • Limit carbohydrates. Low-fat, high carbohydrate diets might increase insulin levels. Choose complex carbohydrates, these raise your blood sugar levels more slowly.
  • Be active. Exercise helps to lower blood sugar levels. By increasing your daily activities and participating in a regular exercise program may treat or even prevent insulin resistance. This will also help to keep your weight under control and reduce your risk of developing diabetes.

Conclusion

Once considered a “man’s disease”, heart disease is a complex illness that affects all genders. We cannot underestimate the risks associated with cardiovascular illness. The more awareness raised, hopefully lifestyle modifications can be explored that will help to prolong and improve your quality of life.

This blog has focused primarily on some causation of hypertension among women. Links have been made to references in order to substantiate some points made. I hope you have enjoyed reading this and has given you ‘food for thought’.

I would welcome any comments that you may have.

Jules

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