Whether your pregnancy is managed by a midwife, obstetrician, general practitioner or through the public health system, there are a number of simple observations which will be performed at each antenatal visit. These observations are intended to plot the course of your health during pregnancy and to identify early warning signs of potentially concerning issues. Perhaps the most common of these observations are checking your blood pressure and testing your urine for the presence of protein. One of the primary reasons for doing so is that a rise in your blood pressure and/or the discovery of protein in your urine can be the first sign of a potentially serious condition called pregnancy-induced hypertension (or pre-eclampsia).

What is Pregnancy-Induced Hypertension?

Your heart utilises a complex network of blood vessels (arteries and veins) to pump blood around your body. The term blood pressure defines the amount of force that is being exerted on your arterial walls in circulating your blood. Hypertension is the term applied when blood pressure is persistently high – when your blood is consistently being pumped through your arteries with a degree of force above the range considered normal.

Hypertension is a relatively common condition affecting approximately one in seven Australian adults. When hypertension occurs during pregnancy it is referred to as pregnancy-induced hypertension. Approximately 10 to 12 percent of women will experience elevated blood pressure during pregnancy, with around 6 percent of women subsequently being diagnosed with pregnancy-induced hypertension (persistently high blood pressure). It generally occurs later in pregnancy after the 28th week, but can occur earlier. Onset can also occur after the birth of your baby.

What are the Early Symptoms of Pregnancy-Induced Hypertension?

As noted earlier in this article the most common symptoms of pregnancy-induced hypertension are:

• High blood pressure (hypertension); and
• Protein in your urine (proteinuria).

It is important to note though that neither of these symptoms are likely to be detected by anyone other than a trained medical professional. Routine antenatal checks during pregnancy are imperative to diagnosing and managing pregnancy-induced hypertension.

What are the Later Symptoms of Pregnancy-Induced Hypertension?

As pregnancy-induced hypertension progresses there are additional symptoms that can develop. Most commonly, pregnancy-induced hypertension can cause the retention of fluid in the body, known as oedema. Oedema is caused by changes in your blood chemistry, combined with pressure being exerted on your pelvic veins by your growing belly. The latter results in a slowing of the return of blood from your lower limbs back to your heart, forcing fluid from your veins into the tissues of your feet and ankles.

Oedema is a common condition in pregnancy which generally develops gradually and occurs in the lower parts of the body. However as a symptom of pregnancy-induced hypertension, oedema occurs suddenly and is not confined to the lower parts of the body, particularly affecting the face and hands.

As pregnancy-induced hypertension progresses it can cause a range of other symptoms including:

• Excessive weight gain due to fluid retention;
• Headaches;
• Vomiting;
• Vision problems, including blurring and flashes in the vision;
• Pain just below the ribs, in the upper abdomen;
• Generally feeling unwell.

Is Pregnancy-Induced Hypertension Dangerous?

Most cases of pregnancy-induced hypertension are relatively mild and ultimately do not create unresolvable issues within pregnancy. Many of these women can still plan for a natural vaginal birth after 37 weeks. However pregnancy-induced hypertension can worsen during pregnancy and place both mother and baby in danger.

Left untreated pregnancy-induced hypertension increases your risk of blood clotting issues, stroke impaired kidney and liver function, fluid on the lungs, seizures (fits) and death. Every day approximately 800 women die from pregnancy or childbirth-related complications world-wide, including pregnancy-induced hypertension. However approximately 90% of these deaths occur in developing countries.

Early detection and management is the key to minimising the risks associated with pregnancy-induced hypertension. That is one of the reasons why attending routine antenatal checks during pregnancy is so important.

Will my Baby Experience any Symptoms of Pregnancy-Induced Hypertension?

The most common symptom of pregnancy-induced hypertension seen in unborn babies is growth slower than that expected for gestational age. This growth restriction occurs because when a mother has pregnancy-induced hypertension, blood supply to the placenta can be poor. This results in your growing baby receiving less oxygen and fewer nutrients than it requires for healthy growth. This condition is referred to as intra-uterine growth restriction.

Obviously this can seriously impact on your baby’s health in-utero and ultimate chance of survival. Intra-uterine growth restriction has been shown to greatly increase the risk of stillbirth. In addition it increases the risk of premature birth, low APGAR scores, hypoxic brain injury (brain damage caused by oxygen deprivation), chronic lung disease, the need for respiratory support and prolonged neonatal intensive care, and ultimately a lower chance of survival after birth.

Who is Most at Risk of Developing it?

Any woman could develop pregnancy-induced hypertension during her pregnancy. However from research we know there are certain factors which increase the risk. These include women who:

• Have had pregnancy-induced hypertension in a previous pregnancy
• Are experiencing a multiple pregnancy (twins or more)
• Are over the age of 35 or under the age of 20
• Are underweight or overweight
• Had diabetes before becoming pregnant (as opposed to gestational diabetes)
• Have kidney disease, or a disorder of the immune system such as lupus
• Have a history of chronic hypertension
• Have a female relative with a history of pregnancy-induced hypertension
• Have a history of alcohol, drug or tobacco use

How is Pregnancy-Induced Hypertension Managed?

Initially treatment of pregnancy-induced hypertension may start with rest at home, but in some cases hospitalisation may be recommended and/or treatment with one of a number of blood-pressure medications deemed safe in pregnancy. These medications will not ‘cure’ the woman of pregnancy-induced hypertension but instead are intended to promote better outcomes for women and their babies.

Management of pregnancy-induced hypertension is essentially a balancing act between promoting the best outcomes for your baby while attempting as far as is possible to protect your health and wellbeing. For instance, while prolonging a pregnancy has no benefit for a woman with pregnancy-induced hypertension it may have significant benefits for her baby, since the degree of prematurity is directly linked to an infant’s likelihood of survival.

In serious cases a caesarean may be recommended to deliver the baby early and promote the best chance of survival for both mother and baby. However this decision must be weighed based on gestational age, the current state of health of mother and child and any other identified risk factors.

As stated a number of times in this article, the first most step in the management of pregnancy-induced hypertension is early diagnosis. This is best achieved through regular antenatal appointments with a suitably trained and qualified practitioner.

Written 20 March 2014

Resources

Better Health Channel. (n.d.). Blood pressure (high) – hypertension. Retrieved March 19, 2014 from http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Hypertension_means_high_blood_pressure

Cleveland Clinic. (n.d.) Pregnancy-induced hypertension. Retrieved March 19, 2014, from http://my.clevelandclinic.org/healthy_living/pregnancy/hic_pregnancy-induced_hypertension.aspx

Cosmi, E., Fanelli, T., Visentin, S., Trevisanuto, D., & Zanardo, V. (2011). Consequences in infants that were intrauterine growth restricted. Journal of Pregnancy. Vol. 2011, 6 pages. doi:10.1155/2011/364381

Health Direct Australia. (n.d.). Pregnancy-induced hypertension and pre-eclampsia. Retrieved March 19, 2014 from https://www.healthdirect.gov.au/article/pregnancy-induced-hypertension-and-pre-eclampsia

NHS Choices. (n.d.). Pre-eclampsia. Retrieved March 19, 2014 from http://www.nhs.uk/conditions/pregnancy-and-baby/pages/pre-eclampsia-pregnant.aspx#clos

NSW Health. (2011). Policy Directive: Maternity – management of hypertensive disorders of pregnancy. (n.d.). Retrieved March 19, 2014, from http://www.health.nsw.gov.au/policies/pd/2011/pdf/PD2011_064.pdf

Preeclampsia Foundation. (2013). Preeclampsia & international maternal mortality: The global burden of the disease. (n.d.). Retrieved March 19, 2014, from http://www.preeclampsia.org/component/lyftenbloggie/2013/05/01/188-preeclampsiainternationalmortalityfactsimpact

Society of Obstetric Medicine of Australia and New Zealand. 2008. Guidelines for the management of hypertensive disorders of pregnancy. Retrieved from http://www.somanz.org/pdfs/somanz_guidelines_2008.pdf