Medical experts still learning about Covid-19 and premature birth

Prime Minister Boris Johnson and his fiancee Carrie Symonds are celebrating the arrival of a healthy baby boy, but there has been speculation about whether he came early.

Ms Symonds’s due date, which was never officially confirmed, had been described as “early summer”, leading to the belief that the arrival was expected in June.

Ms Symonds, 32, revealed this month that she had been in self-isolation after suffering coronavirus symptoms.

The baby comes just weeks after Mr Johnson, 55, was treated in intensive care after testing positive for the virus.

If Boris and Carrie’s baby was due in early June, then it has been born early

Dr Sarah Stock, a senior clinical lecturer in maternal and fetal medicine at Edinburgh University, said: “Preterm birth is birth less than 37 weeks’ gestation.

“If Boris and Carrie’s baby was due in early June, then it has been born early.

“At the moment, we don’t know whether Covid-19 infection causes preterm labour or other pregnancy complications that can lead to early birth.”

She said data is needed on infection rates from lots of pregnant women to understand the effects of Covid-19 on women and their babies, and “we just do not have that yet”.

Alexander Heazell, professor of obstetrics and director of the Tommy’s Research Centre, University of Manchester, said: “This birth would be counted as premature.

“There are mixed data about Covid and preterm birth. A systematic review of Sars-1 and Covid cases thus far suggests the preterm birth rate was roughly double the normal rate.”

Prof Andrew Whitelaw, emeritus professor of neonatal medicine at the University of Bristol, said: “With the scanty information available, Covid-19 does not appear to be a major risk factor for preterm birth.

“There have been reports from China of newborn infants born to mothers with active Covid-19 but the infants have not had serious illness.”

A spokeswoman for the Prime Minister and his partner said both mother and baby are “doing very well” after the birth in a London hospital on Wednesday morning.

It is understood Mr Johnson was present throughout the birth.

The Royal College of Obstetricians and Gynaecologists (RCOG) said that data is still being gathered about the new virus and its impact on pregnancy but “there is no evidence to suggest an increased risk of miscarriage”.

The RCOG said emerging evidence suggests that transmission from a woman to her baby during pregnancy or birth is “probable”.

In the reports of two cases where this seemed likely, both babies were discharged from hospital and are well.

It is important to emphasise that in all reported cases of newborn babies developing coronavirus very soon after birth, the baby was well

In all previously reported cases worldwide, infection was found at least 30 hours after birth.

In a statement, the RCOG said: “It is important to emphasise that in all reported cases of newborn babies developing coronavirus very soon after birth, the baby was well.

“Given current evidence, it is considered unlikely that if you have the virus it would cause problems with your baby’s development, and none have been observed currently.”

It noted there are some reports globally of babies who have been born prematurely to women who were very unwell with coronavirus.

It is not clear whether the virus caused these premature births or whether it was recommended the baby be born early to help the mother’s health and recovery.