Sleep hormone offers first treatment in 50 years for preeclampsia

By Hudson Institute communications. Reviewed by Associate Professor Rebecca Lim

A naturally occurring ‘sleep hormone’ could help prevent early delivery in pregnant women with the life-threatening complication, preeclampsia, a new study has found.

Dr Rebecca Lim outlining preeclampsia treatment discovery.
Dr Rebecca Lim

Hudson Institute of Medical Research and Monash University scientists showed that giving a treatment of the sleep hormone, melatonin to women with severe, early-onset preeclampsia could extend the length of their pregnancy by an average of six days.

The study, a collaboration with Monash Health and the University of Toronto, has been published in the Journal of Pineal Research.

Co-author, Dr Rebecca Lim said melatonin treatment could ‘buy’ crucial time in a pregnancy in women with severe pre-eclampsia. In some of these women, the only option is to deliver the baby prematurely to avoid life-threatening complications.

Dr Lim says melatonin – which helps to regulate our circadian rhythm and is often utilised as a sleep aid – has profound antioxidant and anti-inflammatory properties which bring immense potential in reducing the risks of preeclampsia for mother and baby.

“A severely preeclamptic pregnancy is like a ship that is about to run aground at high speed,” Dr Lim explains.

“The solution to date has been to deliver the baby prematurely to remove the problematic organ, the placenta. Melatonin treatment allows us to slow down the ship and buy crucial time in the pregnancy before we have to finally ‘abandon ship’ and deliver the baby.”

“There have been no material advances in the treatment of preeclampsia for nearly 50 years. Our study shows melatonin could be utilised as an effective adjuvant therapy to help babies develop for longer in the womb, while reducing the damage that preeclampsia causes on the mother’s blood vessels.”

Professor Euan Wallace outlining preeclampsia treatment discovery.
Professor Euan Wallace

Triple impact helping mother and baby

In the Phase I clinical trial, 20 women with severe early-onset preeclampsia were given a melatonin treatment in addition to their normal clinical care. Melatonin was shown to not only be safe – but also beneficial – for their pregnancies.

“Our study shows that melatonin treatment had three different positive impacts,” Dr Lim said.

“It extended the length of their pregnancy by almost one week, buying precious time for the baby’s vital organs to develop and decreasing the need for high blood pressure medications, which all help to create healthier outcomes for both mother and baby.”


  • Preeclampsia affects around 1 in 20 pregnant women and occurs when the placenta (which delivers vital oxygen and nutrition to the baby) doesn’t function properly.
  • Preeclampsia is associated with high blood pressure, fluid retention and protein in the urine. It normally begins after 20 weeks into a pregnancy.
  • Preeclampsia can lead to complications for both mother and baby, including preterm birth, fetal growth restriction and placental abruption. In severe cases, the condition can lead to the life-threatening condition for mother and baby, eclampsia.
  • Preeclampsia can be managed through blood pressure medication, but the only cure is to deliver the baby. If the baby is severely affected by preeclampsia, it may be delivered early.

Collaborators | University of Toronto

Journal | Journal of Pineal Research

Title | Melatonin improves endothelial function in vitro and prolongs pregnancy in women with early-onset preeclampsia

View publication |

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