Pregnancy and High Blood Pressure

Pregnancy is the most important phase of women’s life. Pregnancy is a critical stage and even slight unwanted change in normal process can be vital to both mother and baby. Pregnant women needs to be careful about various aspects like food to be eaten, type of work they can do, what kind of medicines to use or to avoid, type of exercise to be done etc. one important health factor which is necessary to control during pregnancy is blood pressure. High blood pressure (HBP) may risk the life of both mother and baby. More idea about relation between pregnancy and high blood pressure can be acquired form this article. Apart from regulating BP in pregnancy phase, it is equally important to keep eye on BP before and after pregnancy.

High blood pressure Before Pregnancy

Some women’s may already have pre-existing high blood pressure. Some changes which are needed to be done before planning a pregnancy is to have

  • healthy diet
  • regular exercise
  • proper weight depending upon your height
  • quit smoking
  • quit alcohol

Folic acid supplements should also be taken before 3 months of planned pregnancy and should be continued for first 3 months after getting pregnant. If a woman already has HBP, she should consult doctor before planning a pregnancy. He may advice whether you need medicine to control BP or can stop the treatment during early phase of pregnancy you about what kind of drugs are safe during pregnancy. Having HBP doesn’t mean that you shouldn’t plan for pregnancy.

BP lowering drugs for Pregnancy

Pregnancy lasts for 38 to 42 weeks and is divided in to 3 phases called trimester. First 13 weeks (first trimester) is the period during which baby forms. Second trimester is from 14-27 weeks which is very crucial as organ development takes place during this phase and third trimester extends from 28 weeks until the birth and it is the phase where baby gets matures enough to survive. Babies are at most risk to drugs during second trimester phase.

The idea about safety of drugs can be gathered only from animal studies. No clinical study can be done in pregnant women or in women during their reproductive stages, so idea of toxic effects can be acquired only through reports of bad outcomes when pregnant women have inadvertently taken those drugs. Since there is more idea about the safety of older antihypertensive drugs than newer ones, it is recommended for women with high blood pressure to have older generation BP lowering drugs than newer ones either before pregnancy or at early stages of pregnancy.

Methyldopa even if it is considered as an old fashion drugs is the safest and most effective drugs and is suitable for use at all stages of pregnancy. Beta blockers are suggested but after 24 weeks of pregnancy because reports have shown that they may interfere with baby’s growth when given at early stages of pregnancy. Atenolol should be avoided because it leads to impaired baby growth. Less safety data is available for calcium channel blocker so it should be prescribed only if necessary and only at late stages of pregnancy.

Diuretics and ACE inhibitors are should be avoided completely during pregnancy because they may make pre-eclampsia worse. Also new drugs which are less evaluated during pregnancy should be avoided.

Pregnancy and High Blood Pressure

pregnancy and blood pressure

Blood pressure generally falls during pregnancy. The decline in blood pressure is observed in second trimester period and then it slowly rises until the baby is born. During pregnancy, baby fulfils all it’s the nutritional need from the blood supply by mother. Exchange of oxygen and nutrients from mother to baby is done via placenta. It can be understood that as the baby matures, more amount of blood is needed to be supplied to baby therefore blood volume in mother’s body increases which can cause rise in blood pressure. The placenta releases hormones which relax the walls of arteries and veins and they expand to facilitate storage of such large volume of blood and thus BP remains unaffected. However rise in BP may be observed at latter stages of pregnancy. If the rise in BP is observed for the first time in 36 weeks, it is considered as the best time to deliver baby. If BP rises between 24-36 week periods, you may require BP lowering drug to control BP as to delay the labour. The blood pressure for pregnant women above 140/90mmHg is considered as fatal. If BP reads 170/110mmHg, the women need to be hospitalised as she require immediate medical attention. The condition of Rise in blood pressure during pregnancy is known as eclampsia which is discussed in next section.

Pre-eclampsia and Pregnancy

We have discussed that blood pressure falls during pregnancy, but in many situation rise in blood pressure is observed in pregnant women especially at late stage of pregnancy. A situation where blood pressure rises during pregnancy is called as pre-eclampsia. The rise in BP could not be considered as the only parameter suspecting development of pre-eclampsia so, high protein in urine and oedema confirms the presence of pre-eclampsia. No signs or symptoms are observed at the early stages so the only media through which you can detect this disease is via regular antenatal check-up. 5% of women suffer from pre-eclampsia in their first pregnancy.  In majority of pregnant women, pre-eclampsia is developed but in mild form and blood pressure gets normal by itself after delivery of baby. But around 1 woman in 250 may get more severe form of pre-eclampsia. The chances of pre-eclampsia are more in a woman who gets pregnant after age of 40 or if she is already has high blood pressure. It is believed that women with pre-existing high BP has 2-10 times higher risk than women who had normal BP before pregnancy. Also risk increases by 2-4 folds more if there’s a family history of pre-eclampsia and by 10 fold if both mother and sister have suffered from pre-eclampsia during their pregnancy. Also note that about one third women who had pre-eclampsia in their first pregnancy gets mild pre-eclampsia in their second pregnancy. Blood pressure can be controlled in women with pre-eclampsia but it can be cured only after the delivery of baby but there may be risk of death or disability with baby.

But if blood pressure raises too high or no proper measures have been taken to control it, the more serious problem can arise- known as Eclampsia. The word Eclampsia which is derived from Greek word that means ‘flashing light’ because the first thing that women suffering eclampsia sees is flashing lights before fits develop. Fits or seizure is the main symptom of eclampsia. Soon after, condition becomes more severe as women may lose consciousness which is followed by spasm of all muscles and body starts shaking uncontrollably and in symmetrical order. It can be dangerous to both mother and baby. But the cases of eclampsia have dropped down because of developed and proper antenatal care.  Another condition called as fulminating pre-eclampsia, same as eclampsia but more severe because in such situation blood pressure rises suddenly even if no previous sign of rise in BP is recorded. Eclampsia or fulminating pre-eclampsia can be treated by giving BP lowering drugs and delivering baby as soon as possible by inducing labour or through caesarean section. Another way to control fits is by injecting magnesium supplements (Epsom salts).

Pregnancy and high blood pressure are strongly related since the major cause of eclampsia is high blood pressure; let’s focus more on pre-eclampsia because fits can be avoided only if blood pressure is controlled at this stage. Under condition of pre-eclampsia, arteries of placenta are not able to penetrate deep in to the walls of artery and gets narrow by the plaque and clot formation as a result placental blood supply decreases and thus blood volume increases throughout the body which results in rise in BP. pre-eclampsia may lead to premature birth. under this condition baby may be born with less weight, takes more time to establish good feeding pattern or may have physical disability ( in case of severe pre-eclampsia). The pre-eclampsia occurs when BP rises above 140/90 mmHg. You may have mild pre-eclampsia if diastolic blood pressure is between 90-99mmHg, moderate if diastolic BP lies between 100-109mmHg and severe if it goes above 110mmHg. Another way to identify pre-eclampsia is by high blood pressureobserving difference in BP before pregnancy and BP at late stage of pregnancy, if pre-pregnancy readings are not available, observe the difference in BP in early and late stage of pregnancy. If diastolic and systolic BP rises by 15mmHg and 30mmHg respectively, pre-eclampsia is present.

Another parameter that identifies pre-eclampsia is protein content in urine. If the amount of protein secreted in 24hrs period is more than 300mg, presence of pre-eclampsia is confirmed. Urine test is done to determine protein level. The rise in protein level in urine is due to kidney damage. Sometimes during pregnancy, the blood pressure rises so promptly that may results in kidney damage as kidney may not be able to adjust to sudden rise in blood pressure. Be careful while collecting urine specimen, it is normally suggested to take midstream (MSU) specimen by passing out little urine before collecting sample into container.

Next condition is oedema. Let me make you clear that oedema or swelling happens commonly to the pregnant women. If there’s no protein content in urine, and still you observe swelling, it means that you are safe from pre-eclampsia. But in case of pre-eclampsia, excess of protein gets excreted out which causes increase in volume of fluid that leaks out from the wall of capillary and causes swelling in most of the parts of body mainly in legs. Pre-eclampsia can also be suspected when doctors observe poor growth in baby while observing abdomen or when mother reports with decrease in baby movement.

Pre-eclampsia can be treated only by delivering baby. The doctors have to be careful regarding the extent of severity of pre-eclampsia, stage of pregnancy and decide accordingly to induce labour or plan caesarean section. Labour can be induced by breaking your water called as artificial rupture of membrane (ARM) or by giving prostaglandin pessaries or gel into vagina. Oxytocin injection can be given to induce uterine contraction if the above two methods fails.

High Blood Pressure after Pregnancy

Blood pressure drops down during pregnancy or gets elevated in case of pre-eclampsia. But after delivery blood pressure drops down to normal level in 6 weeks’ time period. Under any situation, if your blood pressure stays elevated even after 6 week period you need to start with BP lowering drug. Regular medical check-up is necessary to keep eye on BP level. Next thing to keep in mind is avoid use of drugs that may pass into breast milk in breast feeding women. BP Lowering drugs which are considered safe to be used during pregnancy is also safe for breast feeding women except methyl dopa because it may lead to depression. Thus methyl dopa should be avoided after delivery. Therefore Drugs like calcium channel blocker and beta blocker which are safe during pregnancy can be continued even after pregnancy.

Contraception and High Blood Pressure

Although contraceptives are not related to pregnancy and high blood pressure, but contraceptive medicines doo contribute in raising high blood pressure. There are two forms of contraceptive pills- combined oral contraceptive (COC) progesterone only pills (POP). POP are less effective than COC but effect on blood pressure is less than COC because it was observed that COC increases BP by 5/3mmHg and also risk of heart attack and stroke was more in case of COCs. COCs consists of combination of two different hormones- oestrogen and progesterone. Different generation of progesterone are available and plus point is the fact that drugs of different generation have same effect on heart. Although it was found that risk of venous thromboembolism was more with third generation progesterone like desogestrel or gestodene than second generation drug like levonorgestrol.

Women should stop taking COCs if they already have high blood pressure or any cardiovascular disorder and BP check-up should be done after every 6 months. Switching to POP can be other solution to COC as they are not associated with rise in BP.

Menopause and High Blood Pressure

Menopause is a period in women’s life where her menstrual period eventually stops. Menopause can occur in between age of 45-55 years. Many people believe during menopause phase blood pressure. This is not true because blood pressure normally rises with age and menopause has no effect in blood pressure. During menopause women may observe palpitation and flushing. These symptoms can be avoided using hormone replacement therapy (HRT). it reduces palpitations, flushing or mood swings and sleep disturbances. HRT can also help in reducing risk of osteoporosis and colon cancer. The benefits of HRT may be outweighed by the fact that it may increase the risk of venous thromboembolism, breast cancer and endometrial cancer. Recent studies have shown that HRT my increase the risk of cardiovascular disorder in women who have previously suffer from coronary heart disease. so it is necessary to have BP test for at least 2-3 times in  first 6 months and then after every 6 months if you start undergoing HRT.