Covid-19 risks to pregnant women and their babies outlined in global research review

Published: 12 March 2021

Pregnant women remain at increased risk of severe Covid-19, and their risk of being admitted to intensive care or needing invasive ventilation is higher than non-pregnant reproductive aged women with the virus, an ongoing global study has found.

The research team, including Professor Asma Khalil from the Molecular and Clinical Sciences Research Institute at St George’s, and led by the University of Birmingham and World Health Organization (WHO), found that pregnant women with Covid-19 are at increased risk of severe Covid-19. This was particularly the case for women from ethnic minority backgrounds, or with pre-existing conditions like obesity, high blood pressure and diabetes.

Their research, published in the BMJ, is part of a unique and ongoing living systematic review and meta-analysis of data, which began in April 2020, and follows the researchers’ first publication in the BMJ last August. 

This latest publication details the researchers’ analysis of the results of 192 studies – an additional 115 studies than were included in their August publication - into the impact of Covid-19 on pregnant women and their babies.

The review found that one in 10 pregnant and recently pregnant women attending or admitted to hospital for any reason were diagnosed with confirmed Covid-19. Overall, 339 pregnant women with confirmed Covid-19 died from any cause (0.02% of a total 41,664 women involved in 59 studies). The overall rates of stillbirth and neonatal death are low in women with suspected or confirmed Covid-19, the review found.

The most common clinical symptoms of Covid-19 in pregnant women were fever (40%) and cough (41%), although compared to non-pregnant women of reproductive age, pregnant and recently pregnant women with Covid-19 were more likely to by asymptomatic.

Increased maternal age, high body mass index, ethnic minority background, and pre-existing comorbidity including chronic hypertension and diabetes were identified as risk factors for pregnant women developing severe Covid-19. While there is emerging evidence from the review that pregnancy specific conditions such as pre-eclampsia and gestational diabetes may be associated with severe Covid-19, the authors state that more data are needed to robustly assess the association between pregnancy specific risk factors and Covid-19 related outcomes.

Professor Asma Khalil, author on the paper from St George’s, said: “Existing studies investigating whether pregnant women should be considered a high-risk group for severe Covid-19 report conflicting data. Our living systematic review uses robust methodology to assess the quality of evidence and is continually updated at regular intervals to provide the most recent data. These findings will be crucial in shaping healthcare policy, clinical decision-making, and most importantly counselling pregnant women.” 

Professor Shakila Thangaratinam, corresponding author and Co-Director of the WHO Collaborating Centre for Global Women's Health at the University of Birmingham, added: “Pregnant women and healthcare professionals will need to take into account the additional risks faced by pregnant women with Covid-19 in making decisions such as taking-up of vaccines if offered to prevent Covid-19, and plan management in pregnancy.”

This paper extends a portfolio of work by researchers at St George’s to tackle the Covid-19 pandemic. The University has launched a Coronavirus Action Fund to raise money for vital research into the pandemic and is actively seeking support for a broad research programme involving all parts of the University.

Please see our Covid-19 Guidance webpages for more information on the University’s response to the pandemic.