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Researchers have found that women are more likely to have a preterm birth when exposed to extreme heat and those with pre-existing conditions may have an even higher risk.

Preterm or premature birth, when a baby is born before 37 weeks of pregnancy, is the leading cause of infant death worldwide and many children born early deal with ongoing health problems for the remainder of their lives.

The team from Women and Babies Research at the Kolling Institute and the University of Sydney examined over 918,000 births in NSW over a ten-year period.

The study found about 29,000 or 3.2 per cent of babies were born as a result of preterm birth. Importantly, researchers found that when it was hotter, the risk of preterm birth increased for all women and particularly for women with diabetes, hypertension, chronic illness and those who smoke.

On days where it was hotter than 33 degrees the risk of preterm birth increased by 12 per cent compared with a 20 degree day. This increase in risk was potentially higher for women with diabetes (29%), hypertension (29%), chronic illness (17%) and those who smoked during pregnancy (19%).

Lead study author Edward Jegasothy PhD said it was the first study to link effects of extreme weather and preterm birth in the temperate climate of New South Wales.

“We now have a better understanding of the relationship between extreme heat and preterm births. Our study adds to the growing body of evidence regarding the health impacts of climate change-related exposures. This is particularly important given the increasing temperatures and heatwave events not just in Australia, but globally,” he said.

“These findings are also important given the long term and significant implications of preterm births and the potentially exacerbated risk in mothers with underlying health conditions.”

The findings encourage pregnant women to stay well hydrated and reduce their exposure to extreme heat.

Doctors and researchers are increasingly concerned at the steady rise in premature twin births in New South Wales.

Professor Jonathan Morris and his team from the Kolling’s Women and Babies Research group analysed over 14,000 twin pregnancies from 2003-2014, finding 49 per cent of twins were born premature before 37 weeks, and 69 per cent of all births were planned either by pre-labour caesarean or induction.

“Previous research into singleton pregnancies has shown early birth placed an infant at increased risk of long-term developmental problems,” Jonathan said.

“In the short-term, babies born early were more likely to need help with their breathing, be admitted to a neonatal intensive care unit, have jaundice, spend longer in hospital and be readmitted to hospital in the first year of life.”

Jonathan said while an early planned birth is sometimes necessary, the aim should be to prolong the pregnancy for as long as it is safe to do so.

Lobaba Idris experienced this with her twins Zayn and Layla who were born via planned caesarean at Royal North Shore Hospital at 36 weeks and four days old.

In the last weeks leading up to the birth, Lobaba said every day was a relief. In 2019, Lobaba lost a baby at 21 weeks.

“I was keen to stay pregnant for as long as I could, but I have an autoimmune disease that needed to be monitored, and my baby girl was much smaller than her brother,” she said.

“We tried to wait until I was 37 weeks but she was so tiny we just knew it was the right time to have a c-section.”

Layla was born at just over two kilograms and Zayn was over 2.6 kilograms.

“Waiting as long as we did I think helped. The twins didn’t need to go into special care and could come home,” she said.

Twins are known to be smaller than singleton babies, and the management of their growth poses unique challenges as the wellbeing of both twins has to be considered.

“Use of singleton growth charts to plot the growth of twins are still being used without considering the different growth patterns which could occur in each twin pregnancy,” Jonathan said.

“This leads to healthy, well-grown twins being misclassified as growth restricted, and often results in unnecessary early birth, exposing these babies to problems associated with prematurity.”

In partnership with the NORTH Foundation, Jonathan and his team are raising funds to evaluate and develop fetal growth charts for twin pregnancies.

“The growth charts will ensure the growth of twins are correctly monitored, thereby avoiding unnecessary intervention and making it easier to identify twins who are at risk of complications,” he said.

Study results will also be used to develop national recommendations and inform clinical guidelines to assist clinicians to determine the best time for twins to be born.

To donate to the study, visit https://northfoundation.org.au/how-you-can-help/women-and-babies-research/

A large scale review has found the number of women smoking during pregnancy in NSW has halved, and yet there are still some concerning trends prompting calls for targeted campaigns.

Researchers from the Kolling Institute and the University of Sydney, analysed smoking rates in all pregnancies in New South Wales over a 22 year period from 1994 to 2016.

The Women and Babies Research team found the overall smoking rates during pregnancy have more than halved from 22.1% in 1994 to 8.3% in 2016, with less than one in ten women smoking during pregnancy at the end of the study period. The numbers fell from 19,850 women to 7,820.

Director of Women and Babies Research, Professor Jonathan Morris, said the reduction in numbers was positive and reflected the success of anti-smoking initiatives such as plain packaging and mandatory health warnings.

“The decrease however, was the lowest among younger mothers, under 25, and women from a lower socio economic background,” he said.

“The data indicated the highest rates of smoking were clustered in just four areas, including Hunter New England, South Western Sydney, Western Sydney and Western NSW.

“Over half the women who smoked during pregnancy lived in one these four regions, and up to 21% of women in these areas continued to smoke while they were pregnant.

“These trends are concerning and contributing to poor but avoidable health outcomes, such as stillbirth, neonatal death, low birth weight and preterm birth,” he said.

Associate Professor Tanya Nippita said around 8000 pregnancies each year are exposed to maternal smoking, and we would like to see that figure drop substantially.

“Armed with our research data, we believe the greatest reduction in smoking during pregnancy is likely to come from interventions targeting the four regions with the highest rates,” she said.

“Tailored programs represent the best use of resources, with the potential to achieve the best results.

“This is an important example of strong research data translating to improved public health outcomes,” she said.