Preeclampsia Research Laboratories



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Preeclampsia Research Laboratories

Non profit research

PEARLS is a non profit organization established under the auspices of the Heart Research Institute, Royal Prince Alfred Hospital and Campbelltown Hospital to raise funds to support ongoing research into the cause of preeclampsia in pregnancy.

Professor Hennessy and her team are regarded as leaders in the world in preeclampsia research.

Growing since 2002

Established in 2002 by a small group of interested patients and doctors. At that time it was not known what causes preeclampsia. This condition has been baffling scientists and doctors for over 100 years.

Our mission is to find the cause of preeclampsia, and to develop a screening test which will directly save the lives of the thousands of babies and women who die from this condition every year.

Raising funds

PEARLS aims to raise funds to:

Did you know?

Preeclampsia is the most common complication of pregnancy.

One in 10 women will suffer from preeclampsia during their pregnancy.

Preeclampsia is often called "high blood pressure in pregnancy".

Roughly 780 babies die every day in the world from preeclampsia.

Preeclampsia is the major cause of premature birth.

Over one million women are affected worldwide every year.

Preeclampsia can cause both infant and maternal mortality.

Preeclampsia can cause devastating long term issues such as brain damage and high blood pressure.


1. What is preeclampsia?

Preeclampsia is high blood pressure in pregnancy.

It often occurs in the later stages of pregnancy and is discovered when the blood pressure starts to increase and sometimes when protein in found in the urine test. It is one of the most common complications of pregnancy, affecting one in ten pregnancies.

The most serious effects occur when blood pressure is dangerously high and the pregnancy needs to be delivered early - ending with a premature baby and very sick mother.

The mother can suffer headaches, pain under the ribs and often severe swelling. In the worst cases, the high blood pressure can lead to kidney damage, stroke and even death if untreated.

2. What's in a name?

"Eclampsia" was the Latin term for fitting or seizures.

Untreated, high blood pressure in pregnancy can lead to fitting which is why this condition came to be called preeclampsia.

In normal pregnancy blood pressure goes down. If you have preeclampsia, blood pressure goes up during the pregnancy.

3. Is high blood pressure by itself preeclampsia?


In addition to high blood pressure, a diagnosis of preeclampsia involves protein in the urine, liver pain, headache, blood abnormalities or a baby who has stopped growing.

High blood pressure, without these other problems is the milder form of the disease.

4. What increase in blood pressure and when defines preeclampsia?

Preeclampsia is defined as an increase in blood pressure compared to your first visit to the doctor, if the increase occurs after 20 weeks of your pregnancy. In Australia the critical markers used are a blood pressure reading of over 140/90, or a rise of 25 or more in the first number (the systolic blood pressure) or more than 15 in the second number (the diastolic blood pressure).

If your blood pressure was increased before 20 weeks of the pregnancy, it is likely that you have "essential" or chronic hypertension, rather than the blood pressure being a sign of the disease of preeclampsia. Some women have an increase in blood pressure on the oral contraceptive pill and may also experience higher blood pressure in pregnancy without this being a sign of preeclampsia.

5. Am I at risk for preeclampsia?

High blood pressure or preeclampsia happens to about 5% of all pregnant women in Australia.

There is not yet any screening test to tell a woman whether she is at significant risk of developing preeclampsia. A major aim for PEARLS and our colleagues in preeclampsia research worldwide is to develop a simple, effective and affordable screening test.

We can say, though, that there are circumstances that increase the chances of developing preeclampsia, and which make good medical care in pregnancy particularly important.

Risk is also increased if the mother has a medical condition such as:

6. What do the blood pressure numbers mean?

Blood pressure is defined by 2 numbers: for example, 120 over 80 or 120/80.

The higher number ("systolic blood pressure") reflects the maximum pressure of the blood within the blood vessels (tubing) of the circulation. This maximum burst of pressure occurs with every beat of the heart, when blood is forced by the heart's contraction into the circulation.

The lower number (or diastolic blood pressure) is the pressure measured in between heart beats. This number reflects how full the circulation is.

There is no single normal blood pressure.

Blood pressure measurements taken during a day for any individual person may be very variable. The measurement of blood pressure is affected by the age of the person, whether they are male or female, the level of activity, stress or exercise, sleep, and most importantly, pregnancy.

Common numbers that are recorded when not pregnant are 120/80. When not pregnant, blood pressure is only called high if the readings are taken at rest, repeated several times and go above a set number of 140/90. How this reading is treated will be determined by the age of the person, whether they have other diseases and what medications they may be taking.

In pregnancy, the blood vessels are bathed in all sorts of hormones related to being pregnant. These hormones have the overall effect of lowering the blood pressure by relaxing the blood vessels.

When the circulation is narrowed, or constricted, the blood hits the walls of the blood vessels with increased pressure and the numbers measured are higher. When the blood vessels are relaxed as occurs in normal pregnancy, blood pressure readings are reduced.

Therefore, it is not uncommon to have readings as low as 90/60 early in the pregnancy (often at the first visit to the doctor or midwife at 12 weeks after a missed period). There is no single normal blood pressure in pregnancy. There is a range of numbers that show whether each pregnant woman has responded to the hormones coming from her pregnancy. These numbers are affected by the age of the mother and her usual blood pressure when not pregnant.

The timing of the blood pressure measurement related to the exact number of weeks of the pregnancy is also important. Blood pressure changes between early, middle and late pregnancy. The usual pattern is for both numbers to fall from the first visit to around 24 weeks. It usually stays lower from 24 to 36 weeks and there may be a slight increase blood pressure as the time gets towards delivery. Labour itself does not usually increase blood pressure.

The other unusual feature of blood pressure in pregnancy is that the numbers do not rise as easily in response to activity or stress. This means that the mother keeps her lower pregnant blood pressure even in time of activity and stress that would normally increase blood pressure when not pregnant.

These changes in circulation in pregnancy - lower blood pressure and greater resistance to increases from the body's hormones - seem to be important to keep an adequate amount of blood flowing from the mother's circulation to the placenta which is feeding the baby. The role of the placenta in the control of blood pressure in pregnancy is a major focus of PEARLS and colleagues in preeclampsia research internationally.

7. What risks does preeclampsia present to mother and baby?

With good medical care the most severe complications of preeclampsia for the mother are rare in Australia, even where a woman has other preexisting medical problems.

However, we are dealing with a very serious disease. One of the most difficult issues when preeclampsia is diagnosed is grappling with the decision that possible early delivery will be required. Pre-eclampsia may require prolonged hospital stay and close specialist observation, to protect against risks of:

8. Antenatal care

The regular antenatal vists are designed to increase in frequency in later pregnancy. This increase is in order to assess the likely ability of the baby to be delivered vaginally, and to assess the growth and development of the baby; but of equal importance, the blood pressure and urine are screened for preeclampsia.

If the blood pressure is increased at any time before the delivery, then women may be requested to have more frequent blood pressure readings. They might be asked to visit a day stay unit where the blood pressures are taken for a few hours (rather than a one off reading) and the baby is assessed.

If increased blood pressure alone develops, some units may start tablets to lower the blood pressure (or at least prevent further rises in blood pressure). If other features of preeclampsia occur, such as headaches or liver pain, then admission to hopsital is likely to be required in a multidisciplinary centre such as a major teaching hospital. It is likely that blood pressure specialists will be involved early in the decision about the use of tablets and the possible timing of the delivery.

9. Medications

Common drugs in use in Australia are:

These drugs have different mechanisms of action and so often the plan is to use a combination of two at lower doses rather than go for a big dose of one medication. This reduces the side effects of one medication and gains the benefit of lower blood pressure with less side effects.

The medications are generally chosen depending on the experience of the staff using them.. There is no scientific evidence to support one medication over another.

Needless to say, newer medications are not proven to be safe in pregnancy by as many years of experience and therefore are not recommended.

Clonidine and Methyldopa have been used for several decades and are commonly used around the globe. They have a "central action" whereby they decrease blood pressure.

10. Delivery

Blood pressure elevated during delivery needs to be taken as seriously as in the antenatal period and after delivery. Normal labour does not significantly increase blood pressure.

The reasons for delivery of a baby in preeclampsia relate to the well being of the mother and the baby. If the blood pressure is difficult to control with oral medications or even intravenous medications then delivery to prevent problems from the high blood pressure alone can be required. If the mother is becoming progressively unwell with headache, vomiting or liver pain, then delivery may be recommended. If the blood tests show a deterioration in the platelet count (blood components required to stop bleeding in the delivery), or in the liver or kidney tests, then delivery might be recommended. If the baby is small and or not growing then that is a sign that the placenta is not working properly and that the baby may require early delivery.

The method of delivery depends on the wishes of the mother and her family and carers. The timing of the delivery is also important. If delivery is required earlier than 34 weeks then it is possible that a caesarean section will be recommended. Later in pregnancy a vaginal delivery is the optimal form of delivery depending on the ability of the team to control the blood pressure and also on how well the baby is coping with the delivery process.

11. Care post delivery

Preeclampsia can last as long as 3 months post-delivery. Don't despair, the majority of the symptoms of preeclampsia and the increased blood pressure are gone by the time you are discharged from hospital. If blood pressure continues after delivery then medications can be used that were not necessarily safe when the baby was still in the womb. Fluid tablets can be used if required to help with the fluid problems and high blood pressure of preeclampsia. The blood pressure may need to be checked frequently after delivery until the blood pressure has settled and then the medication can be gradually withdrawn.

12. Future pregnancies

Risk of preeclampsia goes down with each pregnancy with the same partner.

If preeclampsia occurs after 34 weeks of gestation then there is a slight risk of it occurring in the next pregnancy.

If the preeclampsia is discovered prior to 34 weeks of gestation, then the chance of there being an underlying blood clotting disorder, renal disease or auto-immune disease are possibly increased. This is more likely in women with a reason for the preeclampsia, kidney disease and prior high blood pressure.

13. Getting answers to more questions

We cannot promise to answer individual questions on line - apart from resource issues, answering any individual woman's questions about her pregnancy properly requires a thorough individual examination and taking a detailed individual history. If you have concerns about your own pregnancy your first contact should be your own doctor, who can arrange referral to a specialist with more detailed knowledge of preeclampsia if necessary.

However, if you would like to see questions addressed on this site which you cannot find an answer to at present, please contact us and we will seek to add further material as this site develops.


See our Facebook page for past and upcoming events .

If you would like to help us continue in the important work being done by the PEARLS research team, you can assist by donating now.

People behind PEARLS

Our mission is to find the cause of preeclampsia

Connect with Amanda

Amanda Davidson OAM  LLB  BCom


Amanda is a lawyer of over 25 years standing specializing in all aspects of the law relating to major projects and has a long term interest in the promotion of awareness for womens’ health issues.

Amanda had preeclampsia when she was pregnant with her son Harry. Realising how widespread and devastating preeclampsia is, she joined forces with her brilliant doctor to create PEARLS Preeclampsia Research Laboratories.

In 2015 she was awarded a Medal of the Order of Australia (OAM) in recognition of outstanding achievement and service related to her PEARLS initiatives.

Connect with Annemarie

Professor Annemarie Hennessy AM, MBBS, PhD, MBA, FRACP

Managing Director

Annemarie Hennessy is the leader for the Vascular Immunology Group and the Dean and Foundation Chair of Medicine at the Western Sydney University. She has over 20 years experience in preeclampsia research and is actively involved in clinical and laboratory research into the causes of high blood pressure during pregnancy. She directs PhD students at the Heart Research Institute (USYD) and at Western Sydney University.

In 2015 she was inducted as a Member (AM) of the Order of Australia for contribution to Medical Research, particularly in the area of clinical hypertension and maternal health.


Our fundraising committee has been instrumental in raising funds in support of PEARLS activities. Members are:

Amanda Davidson, Alex Perry, Annemarie Hennessy, Campbell Robertson-Swann, Joseph Akelian, Lauren Harvey, Sharon Burns, Stephen Broderick and Tony Harwood.

My inspiration is the mothers. They continue to guide and motivate the whole team in terms of the immediate importance of the work we do: Annemarie Hennessy




Need more information?

Contact Us

The PEARLS laboratories are based in Sydney, Australia at the Heart Research Institute in the Royal Prince Alfred Hospital precinct in Newtown and also at the School of Medicine, Western Sydney University, Campbelltown.

For Charity Auction tickets, donations and enquiries
Amanda Davidson
0418 679 737

PEARLS, Heart Research Institute, 7 Eliza Street, Newtown NSW 2042

Annemarie Hennessy


Preeclampsia Research Laboratories
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