Melbourne’s Covid lockdown restrictions led to fewer preterm births, and researchers want to examine why
Obstetricians and gynaecologists are examining why Covid-19 lockdown restrictions in greater Melbourne seem to have led to a reduction in babies being born early.
A peer-reviewed paper published in the medical journal, Ultrasound in Obstetrics and Gynaecology, and led by Monash Health obstetrician Dr Daniel Rolnik, was conducted across three maternity hospitals in Melbourne. The study included 3,150 women who were pregnant during tough Covid-19 pandemic restriction measures in Victoria during 2020, and 3,175 women who were pregnant before the restrictions were enforced.
Rolnik and his team examined rates of delivery before 34 weeks’ gestation, along with stillbirth and adverse outcomes, in both groups of women. About one in 10 women worldwide give birth preterm, before 37 completed weeks gestation, and it is the single most important perinatal risk factor for infant death or long term physical, neurological or intellectual disability.
“We decided to focus on delivery before 34 weeks rather than 37, because it’s much more clinically important because they are more premature and experience more adverse outcomes, whereas generally those babies born between 34 and 37 weeks are more mildly premature and usually they don’t run into as much trouble,” Rolnik said.
“What we found was a 30% reduction in preterm births in women who were pregnant during lockdown as compared to women who were pregnant before.”
There were 95 women in the lockdown group who gave birth prematurely, compared with 130 women in the other group. There were no significant differences between the groups regarding maternal age, smoking rates, region of birth, or having had previous preterm births.
There was no significant impact on rates of stillbirth between the two groups, but Rolnik said given stillbirth is rare, the sample sizes may not have been large enough to detect differences, and more studies were needed.
Rolnik said it was unclear why pregnancy during lockdown appeared to be associated with lower preterm births, especially in women with a history of preterm births. He said further research hoped to establish whether the reduction was positive because babies were being born with fewer complications, or whether those women experiencing complications and preterm births during lockdown were being seen at other facilities less equipped to provide acute care. This might be because women were reluctant to seek medical care from busier hospitals during a pandemic.
But he said it was likely the lockdown was somehow having a protective effect.
“One of the theories is that women in lockdown were less stressed, not necessarily less stressed psychologically, but physically,” Rolnik said.
“They may have had a lower workload due to restrictions, or been able to work from home.
“The other very interesting hypothesis is that people are getting fewer infections by common pathogens during lockdowns and public health measures, so less influenza for example. Other children not going to school also protects against these infections being brought into the home. Infections can be a reason that someone goes into early labour.”
Other studies conducted internationally during the pandemic have shown mixed outcomes in relation to preterm birth and stillbirth due to public health measures. Lockdowns can differ in terms of measures and restrictions, so direct comparisons can be difficult.
According to a review of international evidence by Safer Care Victoria, “one health region in Ireland reported a reduction in preterm birth of very low birthweight infants during the Covid-19 lockdown, and a similar study in Denmark reported similar reductions during the nationwide lockdown from a stable rate in the preceding five years”.
“In relation to stillbirth, the impact seems to be in the opposite direction,” the review said. “A study undertaken in one hospital in England demonstrated an increase in the stillbirth rate during the pandemic. These data however are not consistent, even within England.”
During the current outbreak in Victoria, all pregnant women who do become infected with Covid-19 despite lockdown restrictions and who develop worrying symptoms are being directed to Monash Medical Centre, a hospital in Clayton, where Rolnik is among the staff treating them.
Currently the hospital has two pregnant women admitted with Covid-19. Neither are fully vaccinated. Pregnant women were only made a priority group for vaccination by the federal government in August, despite expert advice deeming it safe earlier.
“They developed some pretty significant symptoms requiring admission, but they are stable at the moment and hopefully they will be OK,” Rolnik said.
“It is why vaccination for pregnant women is very important. At the moment, we are able to care for our pregnant cases in hospital quite well because the numbers are low and we are able to offer every help we can.”