When can my blood pressure rise during pregnancy?
If your blood pressure rises because you are pregnant, it is called gestational hypertension or pregnancy-induced hypertension (SiH). It is referred to only if your blood pressure rises after the 20th week of pregnancy.
If you have high blood pressure before week 20, you probably already had it before you became pregnant. In this case, your doctor tells you that you have chronic hypertension. That just means that she existed before.
Your doctor can tell you if your blood pressure is high when he / she reads the results after the test. He / she measures twice in a row to be sure. Your blood pressure is high if both measurements yield blood pressure readings greater than 140/90.
How often does high blood pressure occur during pregnancy?
High blood pressure is quite common. About one in ten expectant mothers is affected (Duley 2009). The likelihood of your blood pressure rising is greater if you are overweight.
You may want to calculate your body mass index (BMI). You can use our BMI calculator. You need to use your weight before pregnancy to get the right results.
If you calculate your BMI, you may find it easier to know how likely you are to get high blood pressure. Weight and blood pressure are related.
For example, a high BMI of 30 or more increases the likelihood that you will get high blood pressure fourfold.
Is high blood pressure in pregnancy questionable?
High blood pressure during pregnancy is usually treatable and you and your baby will be closely monitored. But this is really essential because hypertensive pregnancy is responsible for 15-20% of very rare maternal deaths during pregnancy, birth and postpartum.
The earlier your blood pressure rises during pregnancy, the greater the likelihood that you will get pre-eclampsia later. This pregnancy disorder can affect the work of the placenta. If the placenta is not working as well as it should, it can affect your baby's growth. It will not get enough nutrients and oxygen.
Your doctor will examine your urine to see if it contains protein because this, together with high blood pressure, confirms preeclampsia (CKS 2006) as a diagnosis. If you are overweight, your doctor will pay special attention to signs of pre-eclampsia. The likelihood of getting preeclampsia is greater if you are overweight (Kabiru and Raynor 2004).
The most important thing in preeclampsia is to recognize them early, so you and your baby can be monitored and treated. Therefore, it is very important that you go to all your checkups. Your doctor or midwife will measure your blood pressure every time. It is important to control it because you may not be able to say on your own whether your blood pressure is too high.
If the measurements result in pregnancy-induced or chronic hypertension, you may be prescribed medication to lower your blood pressure. These medications are safe for you and your baby (RCOG 2006, NCCWCH 2008, Duley 2009).
If your blood pressure rises too much, you may need to go to the hospital. There, you will be given medication to adjust your blood pressure (which will not harm your baby) and also monitor your baby carefully. If there are signs of growth problems in the baby or your condition gets worse, you will be suggested to initiate the birth artificially or to make a caesarean section. "Depending on the gestational age and the extent of pre-eclampsia, the only option for therapy may be induction or caesarean delivery," says gynecologist Dr. Birgit Kaliner.
What happens after the birth of my baby?
If your pre-pregnancy blood pressure was normal, it will likely return to normal within 12 weeks of your baby's birth (CKS 2006). If he does not return to his normal state, then you did not have any pregnancy-induced hypertension. You have chronic hypertension. This means that the blood pressure is high even after the birth of your baby. If this is the case, your doctor may recommend that you take medicines to make sure your blood pressure stays at a healthy level.
Learn about blood pressure during pregnancy.
Abrams BF, Laros RK. 1988. Overweight and pregnancy complications. Int J Obes. 12:293-303
CKS. Of 2006. Hypertension in pregnancy. Clinical Knowledge Summaries. cks.library.nhs.uk. [As of March 2010]
Duley L. 2009. Pre-eclampsia, eclampsia and hypertension. Clinical Evidence. clinicalevidence.bmj.com [as of March 2010]
Kabiru W, Raynor BD. 2004. Obstetric outcomes associated with increase in BMI category during pregnancy. AmJ Obstet Gynecol 191:928–32
NCCWCH. Of 2008. Antenatal care: routine care for the healthy pregnant woman. National Collaborating Center for Women's and Children's Health, Clinical Guideline. London: RCOG Press. www.nice.org.uk [pdf-document, as of March 2010]
Weiss JL, Malone FD, Emig D, et al. 2004. Obesity, obstetric complications and cesarean delivery rate - a population based screening study. At the J Obstet Gynecol 190:1091-7