Pregnant women are at increased risk of severe Covid-19 if they are from ethnic minority backgrounds, or if they have pre-existing conditions like obesity, high blood pressure and diabetes, a global study has found.

Up until now, those who are pregnant have been listed as ‘clinically vulnerable’ by the NHS, but the extent of this risk was not fully known.

The NHS website states: “There’s no evidence if you’re pregnant you’re more likely to get seriously ill from coronavirus, but pregnant women are in the moderate risk (clinically vulnerable) group as a precaution.” This is because pregnant people are typically deemed more at risk from viruses such as flu.

But new research led by the University of Birmingham and the World Health Organisation (WHO) suggests the risk of pregnant women being admitted to intensive care or needing ventilation is higher than non-pregnant reproductive-aged women with the virus.

The risk of pregnant women being admitted to intensive care still remains low at around one in every 5,000 pregnant women, Dr Edward Morris, president of the Royal College Obstetricians of Gynaecologists (RCOG), tells HuffPost UK. 

The new research, published in the BMJ, is part of an ongoing systematic review and meta-analysis of data, which began in April 2020.

The analysis of 192 studies looked at the impact of Covid-19 on pregnant women and their babies. It found one in 10 pregnant and recently pregnant women attending or admitted to hospital were diagnosed with confirmed Covid-19. They also had an increased risk of admission to an intensive care unit, receiving invasive ventilation and needing oxygenation treatment.

Dr John Allotey, of the University of Birmingham-based WHO Collaborating Centre for Global Women’s Health, said: “Pregnant women should be considered a high risk group, particularly those identified to have risk factors, for severe Covid-19 based on our findings.”

Risk factors in pregnancy

The study found pregnant women in the following groups were more likely to end up with severe illness and/or complications related to Covid-19:

• Increased maternal age,
• High body mass index (BMI),
• Non-white ethnicity,
• Pre-existing comorbidity including chronic hypertension and diabetes.

There was also emerging evidence from the review that pregnancy-specific conditions such as pre-eclampsia and gestational diabetes may be associated with severe Covid-19, however the authors said more data is needed.

Symptoms of Covid in pregnant women

Compared to non-pregnant women of reproductive age, pregnant women with Covid-19 are more likely to be asymptomatic, the study found. 

Previous research has also found this. The PregCOV-19 Living Systematic Review found an estimated 74% of women were asymptomatic, while another study from the US reported that 86% of women who were admitted in labour and who tested positive were asymptomatic.

When pregnant women do show symptoms, the most common ones are fever (40%) and cough (41%). Less frequent symptoms include difficulty breathing (21%), muscle pain (19%), loss of sense of taste (14%) and diarrhoea (8%). 

What about the risk to babies?

The review found the overall rates of stillbirth and neonatal death are low in women with suspected or confirmed Covid-19. Dr Allotey said mothers should be reassured that the risks to their babies is “very low”. 

It is possible for mothers to pass the virus on to their babies before birth, states the NHS, however when this has happened, the babies have recovered. There’s no evidence coronavirus causes miscarriage or affects how a baby develops in pregnancy.

Pregnant women with Covid-19 are more likely to experience preterm birth and their babies are more likely to be admitted to a neonatal unit, the review found.

Pregnant women and the Covid vaccine

Pregnant women are not offered the Covid vaccine unless they are considered high risk – either because of an underlying health condition or their job. 

What should pregnant women do now?

Pregnant women are urged to consider taking precautions to avoid catching the virus. This includes: washing hands regularly, staying at home as much as possible, practising social distancing and staying away from anyone who has symptoms of coronavirus.

Prof Thangaratinam said the new research “is crucial” to address important research questions and to shape healthcare policy and clinical decision-making.

In response to the study, Dr Morris, from the RCOG, said the findings support previous data that shows the majority of pregnant women with Covid-19 will experience mild or moderate symptoms, “but for pregnant women who are in their third trimester of pregnancy or have pre-existing medical problems, they are at a higher risk of developing severe illness”.

Despite it being almost a year into the pandemic, he said “there is still no robust data from the UK comparing pregnant and non-pregnant women with Covid-19”.

“This data gap extends to the Covid-19 vaccine and whether pregnant women will routinely be offered it,” he said. “So far none of the vaccines have undergone specific clinical trials in pregnant women, something that urgently needs to change.”

RCOG is encouraging pregnant women to contact their maternity team if they have any concerns about their or their baby’s health.

A Department of Health and Social Care spokesperson told HuffPost UK vaccines should only be considered for use in pregnancy when the potential benefits outweigh any potential risks for the mother and baby. “Women should discuss this with their GP, or other healthcare professional, and reach a decision based on individual circumstances,” they said.

“We continue to closely follow the independent recommendations of our scientific and medical experts at the Joint Committee on Vaccination and Immunisation, who advised the vaccine should be considered for pregnant women when risk of exposure to the virus infection is high and cannot be avoided, or if the woman has underlying conditions that place her at a very high risk of complications of Covid-19.”