by University of Oxford

Credit: AI-generated image

Researchers from the University of Oxford, in collaboration with the Royal College of Obstetricians and Gynaecologists, the Universities of Leeds and Birmingham, Kings and Imperial Colleges London, have published new research that suggests pregnant women are no more likely to become ill with severe COVID-19 than non-pregnant woman. However, the majority of women who did become severely ill were in their third trimester of pregnancy, emphasising the importance of social distancing for this group.

The study, published today as a pre-print, looked at 427 pregnant women admitted to hospitals in the UK between 1 March and 14 April 2020 with confirmed COVID-19 (4.9 women out of every 1000 pregnant women, suggesting pregnant women are not at a higher risk of experiencing severe illness). Information for the study was collected from all 194 hospitals in the UK with a consultant-led maternity unit.

Pregnant women from black and ethnic minority backgrounds were more likely to be admitted to hospital for COVID-19. This inequality persisted even when women from London, the West Midlands and the North West were excluded from the analysis, meaning the difference cannot be explained by higher rates of COVID-19 infection in those areas.

The analysis also showed that older pregnant women, those who were overweight or obese, and pregnant women who had pre-existing medical problems, such as high blood pressure and diabetes, were more likely to be admitted to hospital with the infection. Women who were admitted to hospital with COVID-19 in pregnancy were less likely to smoke than a group of comparison pregnant women.

Other important findings from the study include:

• One in five babies born to mothers hospitalised with COVID-19 were born pre-mature and were admitted to a neonatal unit

• One in twenty babies born had a positive test for COVID-19, but only half of them immediately after birth

Sixty percent of the women admitted to hospital have now given birth, while the remaining forty percent have ongoing pregnancies. Most women have now been discharged home. Around one in 10 women required intensive care, and sadly five women have died.

Outcomes for babies born to mothers with COVID-19 were mostly good. Although almost one in five were born prematurely and were admitted to a neonatal unit, fewer than twenty babies were born very premature (when their mothers were less than 32 weeks pregnant). One in twenty babies born had a positive test for COVID-19, but only half of these babies had positive test immediately after birth, suggesting that transmission of infection from mother to baby is low.

Professor Marian Knight, Professor of Maternal and Child Population Health at the Nuffield Department of Population Health, University of Oxford and lead investigator for the study, said, "A very small number of pregnant women do become severely ill with COVID-19 and sadly some women have died. Our thoughts must remain with their families. It is concerning that more pregnant women from black and minority ethnic groups are admitted with COVID-19 in pregnancy and this needs urgent investigation.

"Most pregnant women who were admitted to hospital were more than six months pregnant, which emphasises the importance of continued social distancing measures in the later stages of pregnancy. Following the current guidance about careful social distancing will help prevent infection."

Edward Morris, President of the Royal College of Obstetricians and Gynaecologists and an author on the study, said, "Admission with infection in pregnancy is also associated with older maternal age, overweight and obesity, and the presence of pre-existing medical conditions. Awareness of these factors is important for both women and their doctors and midwives to help ensure women receive appropriate advice about prevention and complications of COVID-19 are recognised early. Detailed advice and guidance for women is available on the RCOG website."

Gill Walton, Chief Executive of the Royal College of Midwives, said, "During this current crisis, pregnancies have continued, babies have been born, and, throughout it all, midwives have been at their side, supporting and caring for them. It's absolutely vital that women continue to attend antenatal appointments to ensure that they and their babies are well. Staying in touch with their maternity services team will help put any concerns at ease and enable them to act quickly when necessary."

Information for the study was collected using a research system called the UK Obstetric Surveillance System (UKOSS).

More information: Characteristics and outcomes of pregnant women hospitalised with confirmed SARS-CoV-2 infection in the UK: a national cohort study using the UK Obstetric Surveillance System (UKOSS). (preprint): www.npeu.ox.ac.uk/downloads/fi … annual-reports/UKOSS%20COVID-19%20Paper%20pre-print%20draft%2011-05-20.pdf

Provided by University of Oxford