During pregnancy, it is recommended to have a medical appointment on a regular basis. At each antenatal appointment, the Doctor / midwife takes a note of the blood pressure of the pregnant lady to measure the level of BP; it should be normal. Normal BP is a vital part of ensuring the health of the mother and baby during pregnancy.
Change in BP in pregnancy
A little change in the Blood Pressure (BP) is usual in pregnancy. These variations can be due to hormonal changes. The Progesterone hormone relaxes the blood vessels walls, thus reducing the BP in the 1st trimester and 2nd trimester. There is a fainting sensation or dizziness associated with low BP, especially when there is a long period of standing or when the lady gets up too suddenly.
In the midst of the pregnancy, the BP reaches its lowest level and then later rises back gradually after 24 weeks of pregnancy. During this time, you might have made that extra liter of blood that the heart pumps all around the body. It might return to normal or to pre pregnant level in the last few weeks prior to the birth of the baby.
Causes of change in BP
• Blood circulation expands in pregnancy
• Hormonal changes
• Dilation of blood vessels
• Alterations in Progesterone hormone levels
Measurement of BP
Monitoring is done at every antenatal appointment and a record of the measure of the level of BP is done by the mid wife / nurse. Depending on these values, further examination, tests and care is prescribed.
The BP is measured by the midwife / nurse using the following steps
• She will advise you to remove any tight clothing worn on the arm.
• She will cuff a wrap around the arm at a level above the elbow.
• She will then pump air into the cuff.
• This inflates the cuff temporarily hindering the blood flow for a brief period.
• The blood flow stops in the primary blood vessel in the cuffed arm.
• There is a tightening feeling but it does not hurt too badly.
• This cuff filled with air is gradually released.
• This cuff is connected to the monitor that analyses and gives the measure of BP.
• The final value is displayed on the screen of the monitor.
• The value displayed on the screen is noted by her.
• There are 2 values: systolic BP and Diastolic BP
• The first one or the systolic BP is the value of BP as the heart pumps the blood out around the body.
• The second one or the diastolic BP is the value of BP as the heart relaxes in between the beats.
• The BP value on an average should be about 110/70 for systolic and 120/80 for diastolic.
• Once the values are obtained and studies, she would inform you regarding the results – high or low BP.
Why emphasize on measuring the BP during pregnancy
• BP value tells you the condition of pregnancy – whether normal or with issues. If there are serious issues like preeclampsia then the midwife shall be looking for its symptoms as it is a risk in pregnancy.
• Preeclampsia can cause high BP and related issues. Along with BP, even urine tests are done in this condition. Protein presence in the urine and high BP are signs of preeclampsia. Earlier gestational hypertension poses a higher chance of getting preeclampsia.
• Both ways, regular BP check up and urine checkups are done during antenatal appointments for monitoring mother’s health.
Low Blood Pressure
A drop in BP is also not uncommon in pregnancy. The dilation in blood vessels due to hormonal changes leads to decrease in BP in pregnancy. It starts to lower in initial stages of pregnancy.
Symptoms experienced during Low BP in pregnancy
A severe lowering of BP can lead to organ damage which includes:
• Kidney failure
• Heart attack
In pregnancy, the BP drop is variable. In general the systolic BP lowers by 5-10Hg whereas the diastolic BP lowers by 15mmHg which return back to normal after pregnancy.