Low BP and pregnancy
Your blood pressure will rise and fall throughout the day depending on what you’re doing and it’s normal for it to change more during your pregnancy. Your body will be producing hormones, particularly progesterone which helps to relax the walls of your blood vessels and will likely cause your blood pressure to fall during your first and second trimester.
As you approach your third trimester your blood pressure will start to increase again and should be back to pre-pregnancy levels a few weeks before the birth of your baby.
It is important to monitor the blood pressure because a condition – Preeclampsia can develop, that can cause serious problems for you and your baby if it goes undetected. Your doctor will test your urine and check your blood pressure for signs of this condition.
The increased circulating blood volume at this stage of your pregnancy is to help your womb cope with the extra demands of your growing baby and is also a preparation in anticipation of a normal blood loss (about 500mls or two cups) when you give birth. Thanks to the pregnancy hormone oestrogen that helps the heart and blood vessels to cope with this extra volume, your blood pressure quickly settles down to what it should be– 120/80 mm Hg (mercury).
While there isn’t a definitive number that is too low, there are symptoms that are associated with low blood pressure:
cold, clammy skin