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Elevated Blood Pressure
Definition of Blood Pressure (BP)
Definition of Blood Pressure
The blood pressure is the force exerted against the arterial walls, dependent on the energy of the heart action, the elasticity of the walls of the arteries and the volume and viscosity of the blood. The two types of pressure measured are:
Systolic - This pressure occurs during heart contraction and is found at it's maximum pressure near the end of the stroke output of the left ventricle of the heart. The blood leaves the ventricle and is pumped through the parts of the body. When a reading is taken, this is the top number (e.g., the 140 in a 140/90 BP reading - and read as "140 over 90").
Diastolic - This pressure occurs when the heart is at rest and relaxes and is found at it's minimum pressure, filling with blood before the next contraction. This is the lower or bottom number (e.g., the 90 in a 140/90 BP reading).
The units in which BP is measured is "mmHg", meaning millimeters of mercury. The BP reading is an evaluation of how hard the heart must work in order for the blood to adequately circulate throughout the body. Pathologically high blood pressure (hypertension) is a serious concern which may represent or signal an underlying "dis-ease" problem in the body. High BP may contribute to or help bring about cerebral hemorrhage, cardiac arrest, headaches, visual problems, etc. In pregnancy, it is associated with convulsions, toxemia (eclampsia), and abruptio placentae.
However, it cannot be assumed that hypertension (high BP) appearing in pregnancy is always a problem.
A normal, healthy person's BP changes constantly and can vary 30 to 50 mmHg due to exercise, a ctivity, rest, temperature, time-of-day and nervousness, anxiety or stress levels. A simple visit to a physician's office for a blood pressure check can raise the BP reading by 15 to 20 mmHg due to "doctor's office anxiety". It is important to know the client's regular "at home, relaxed" blood pressure.
In pregnancy there is a drop in blood pressure in the second trimester followed by a rise in the third. This is related to normal blood volume expansion and is entirely physiological, not pathological. In a well nourished woman, the blood pressure may vary a great deal and not reflect any increased risk to mother or baby.
Hypertension in Pregnancy
Prior to 1972, the definition was a pressure of 140/90 or higher on any two occasions six hours apart. The redefinition of hypertension in pregnancy places many healthy women into a new "high-risk" catagory.
Checking Blood Pressure Accuracy
Interpreting Blood Pressure Readings
Low blood pressure (hypotension) readings are often found in young women, women who exercise regularly, and vegetarians. Symptoms of low BP include nausea, dizziness on rising, fainting, visual disturbances and breathlessness with exertion. These symptoms can be remedied by rising slowly and correcting hypoglycemia if the problem is low blood pressure.
Benign blood pressure elevations in a well-nourished, well-hydrated woman may be due to: a. Multiple gestation with the extra blood volume causing a normal rise in BP.b. Technical errors by health care provider, midwife, birthing assistant or technician. Review of BP taking instructions is required and recheck BP later in prenatal visit with client.
c. A lack of sodium (salt) in an otherwise well-nourished, well-hydrated woman can cause edema and high or elevated BP. Be sure she is salting her food to taste and using more if she is sweating and/or during hot weather.
d. Obesity is often associated with high bp readings due to inaccurately sized bp cuff. Be sure to have an appropriately sized bp cuff. If the reading is correct and her diet is good, then this is not a cause for concern.
e. Maternal stress or anxiety may also effect blood pressure, causing a rise. Some women have "labile" BP, which means they have "rapidly changing" blood pressure. Readings will rise significantly when they are stressed or have anxiety. Sometimes this will manifest during medical examinations (called white coat hypertension), during an exceptionally busy or hectic day or with the excitement of the onset of labor. If this occurs, then the midwife should wait until later in the prenatal or labor visit to do the BP check. This allows the woman to have a chance to relax before the blood pressure is taken. If high, retake again later with the woman in a reclining position. A decline in BP is usually seen at this time. If not, choices can be made by the midwife to either not worry about it since the woman's diet is good or a relative can retake the blood pressure at the woman's home and relay the information to the midwife. This latter choice will often reveal a lower blood pressure reading than was seen during the midwife's visit.
Essential hypertension may pre-exist pregnancy or may reveal itself during pregnancy. This may be a manifestation of repeated blood pressure checks during visits and possible anxiety from having it checked frequently (much more often than when the woman is in a healthy, non-pregnant state). Essential hypertension results from no known cause and commonly appears with age. Young black women will often exhibit this type of hypertension. Usually this type of hypertension is managed with hypertensive drugs, and in pregnancy with low sodium, low calorie diets and diuretics. Such medical management has led to a higher risk catagory and poor outcomes for these women. Recent studies have shown that undrugged and unrestricted hypertensive women can and do grow big, healthy babies having healthy placentas. They are not considered high risk on a proper nutritional diet adequate in protein, calories and nutrients for pregnancy.
Remedies For Benign Hypertension
Serious Causes of Hypertension & Underlying Problems
The physiology of toxemic hypertension is the body is trying to adequately nourish an extra organ (the placenta) without sufficient blood volume to do so. Pressure rises in an attempt to compensate while vessels constrict as edema causes pressure. A concentrated blood volume and poor prostaglandins production may cause abnormal platelet aggregation in the vessels increasing BP more. Headaches and blurred vision are symptoms of pressure in the brain and often precede convulsions. Abruption may occur as pressure pushes a poorly attached placenta away from uterine wall.
1. The midwife should advise the client on signs and symptoms of increasing severity of pre-eclampsia (epigastric pain, severe headache, blurred vision or stars, edema of the face, hands and ankles, convulsions).
2. The midwife should consider appropriate baseline labwork particularly if there is a history of pregnancy induced hypertension (PIH) or pre-eclampsia. Tests may include:
Routine urine "dipstick" analysis for protein and glucose at each prenatal visit. If protein is found, it is important to exclude a urinary tract infection (UTI) which may be present in spite of the lack of symptoms.
Urine microscopy & culture. This is done when protein has been found in the urine to exclude UTI. A midstream specimen with a bacterial count of less than 100,000/mm3 are unlikely to indicate active infection, especially if a significant white-cell count is not found in the urine. Bacterial counts between 10,000 and 100,000/mm3 are of borderline significance and a further urine sample should be obtained.
Serum urea and creatinine. The lower levels of serum urea and creatinine in normal pregnant women compared with non-pregnant clients/patients reflect the increased glomerular filtration rate which occurs during normal gestation. In PIH, especially if associated with proteinuria, the serum levels are higher than in normal pregnancy although usually within non-pregnant range. Levels above this range suggest underlying chronic renal impairment either as a cause or as a result of pre-existing hypertension. An acute rise in blood urea may occur in acute renal failure which sometimes accompanies eclampsia.
Serum electrolytes. Serum sodium and potassium concentrations are generally lower in normal pregnancy than in normal non-pregnant women. The administration of potassium-losing diuretics will aggravate this.
Serum uric acid. Like the blood urea, this is lower in normal pregnant women than in non-pregnant women due to the increased renal clearance. It is usually raised in the stage of pre-eclampsia, and a rising level in a woman with high blood pressure in the last trimester may be an indication of impaired fetal outcomes.
Blood film and platelet counts. The hemoglobin should be checked frequently in a pregnant woman. If she is severely hypertensive and has symptoms of severe pre-eclampsia there may be evidence of reduced platelets, increased reticulocytes and abnormally shaped red blood cells. 3. A complete prenatal check should be performed. Based on results of this prenatal:
High BP with no symptoms of pre-eclampsia, advise client to assume left lateral lying position 3-4 times daily for 30 minutes for 2 days. Review diet and lifestyle, and recommend complimentary therapies. If the blood pressure is still elevated, the woman should consult with her health care provider.
If high BP is accompanied by signs and symptoms of pre-eclampsia such as significant proteinuria, weight gain greater than 3 lbs in one week, and/or edema or other symptoms.
a. The woman should advise her health care provider immediately, she may anticipate possible hospitalization and IV therapy, bed rest and additional labwork.
b. The midwife should advise client to increase fluids and dietary protein.
Managing Hypertension in Labor & Postpartum
If is normal during the effort of labor and birth for the BP to be elevated. Women do not suddenly become toxemic after a perfectly healthy and well-nourished pregnancy, although this myth is commonly supported by the medical professional by labeling a hard working, laboring woman high risk when she has a rise in BP and protein in her urine from the normal stress she is experiencing from her labor.
If a woman is having increasingly severe and unresolvable symptoms associated with high BP in labor, it is appropriate to transport her to a medical facility. Symptoms include throbbing headaches, visual disturbances, or other problems which seem to be unrelated to the labor process. Although toxemia doesn't simply appear out of nowhere, it is possible for a woman to have seizure activity or other severe problems precipitated by the stress of labor which are not toxemia but are very serious.
In client cases of low BP, there are some herbal supplements which are contraindicated for use in labor. Herbs such as Blue Cohosh and Lobelia are a few contraindicated for low blood pressure problems. The midwife should check with good herbals or consult with a herbal health care provider regarding use of any herbal supplements that she may be unfamiliar with if she has a woman with BP range in one extreme or the other.
If every thing is fine, postpartum and bleeding is well under control and all is well, the midwife will probably not need to recheck the BP. Birth is a normal process. However, if bleeding is not under control or the woman is feeling light-headed or simply "not right", the placenta may be taking awhile to deliver or for any reason the midwife may be concerned, then by all means the blood pressure should be checked and rechecked often to see if the problem can be found and remedied.
In cases of hemmorhage, the midwife will often see a rise in blood pressure before it drops, as the body tries to compensate for the blood loss by making the heart work harder. Drugs often used in labor and postpartum, such as Pitocin, Ergotrate and Methergine, all raise the blood pressure, but if a woman is bleeding, this may be desirable. The midwife should listen to the birthing woman and not discount what a woman is telling her if she feels something isn't right. Internal bleeding (as with a hemotoma, for example) can be life threatening. If pain is accompanying a drop in blood pressure, with or without external hemmorhage signals, then bleeding is probably happening and should be thoroughly checked out as soon as possible. This type of bleeding may occur prior to birth from an abruption or placenta previa or after the birth with tears or a hemotoma. Obvious bleeding usually eliminates the pressure buildup, which can occur with painful concealed bleeding. In this situation, elevate the affected body and transport as necessary.
Information was obtained from "Understanding Lab Work in the Childbearing Year,
A guide for practitioners and consumers of health care in childbirth" by Anne Frye.
Thank you Anne.