Pregnant women with coronavirus are more likely to need intensive care and give birth early, finds study
However, they are less likely to show symptoms of Covid-19. Being overweight, older and having other pre-existing medical conditions increase their risk of having a more serious disease
Pregnant women are thought to be a high-risk group for Covid-19 infection and there are concerns about potential adverse effects of the virus on both mother and baby. However, published reviews on Covid-19 in pregnancy quickly become outdated as new evidence emerges. A new study now helps to shed light on the risks of Covid-19 for pregnant women and their babies.
An international team of researchers has found that pregnant women seen at the hospital with suspected or confirmed Covid-19 are less likely to have fever or muscle pain and symptoms of the disease, but seem to be at an increased risk of needing intensive care than non-pregnant women of similar age.
The findings also reveal that pregnant or recently pregnant women with Covid-19 are more likely to give birth prematurely and their newborns are more likely to be admitted to a neonatal unit. Researchers found that 1 in 4 of all babies born to women with Covid-19 were admitted to a neonatal unit, but data on causes of preterm births or indications for admission to neonatal units among these babies are lacking. Stillbirth and newborn death rates, however, are low.
"We found that one in 10 pregnant or recently pregnant women who are attending or admitted to hospital for any reason are diagnosed as having suspected or confirmed Covid-19, although the rates vary by sampling strategy. The Covid-19 related symptoms of fever and myalgia (muscle pain) manifest less often in pregnant and recently pregnant women than in non-pregnant women of reproductive age. Whereas testing for SARS-CoV-2 (the virus that causes Covid-19) in non-pregnant women is based on symptoms or contact history, testing in pregnant women is usually done when they are in hospital for reasons that might not be related to Covid-19," write the authors in the study published in BMJ.
The paper is a “living systematic review” that compares the clinical features, risk factors and outcomes of Covid-19 in pregnant and recently pregnant women with non-pregnant women of similar age. It has been led by experts at the University of Birmingham, UK, the World Health Organization (WHO), the UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), and other collaborators. Living systematic reviews are useful in fast-moving research areas such as Covid-19 because they can be updated regularly as new information becomes available.
"With the establishment of several national and global prospective cohorts, we expect the sample size of our meta-analysis to increase further in the coming months. Our living systematic review and metaanalysis, with its regular search and analyses updates, is ideally placed to assess the impact of new findings on the rapidly growing evidence base," the researchers emphasize.
Dr Edward Morris, president of the Royal College of Obstetricians and Gynaecologists, who was not involved in the study, says that while overall risks to pregnant women from coronavirus are low, the findings of this study highlight the particular risks to pregnant women, especially those in the third trimester of pregnancy, should they become unwell with coronavirus. "Pregnant women are included in the list of people at moderate risk as a precaution and pregnant women should, therefore, continue to follow the latest government guidance on social distancing and avoiding anyone with symptoms suggestive of coronavirus," he suggests.
The report is based on 77 studies reporting rates, clinical features (symptoms, laboratory and X-ray findings), risk factors and outcomes for 11,432 pregnant and recently pregnant women admitted to the hospital and diagnosed as having suspected or confirmed Covid-19. The studies were designed differently and were of varying quality, but experts were able to allow for that in their analysis.
Compared with non-pregnant women of reproductive age, the investigators found that pregnant and recently pregnant women with Covid-19 were less likely to report symptoms of fever and muscle pain, but they were more likely to need admission to an intensive care unit and invasive ventilation. The odds of giving birth prematurely was also higher in pregnant and recently pregnant women with Covid-19 compared to those without the disease. A quarter of all babies born to mothers with Covid-19 were admitted to a neonatal unit and were at increased risk of admission than those born to mothers without the disease.
Marian Knight, professor of maternal and child population health, Nuffield Department of Population Health, University of Oxford, who was not involved in the study, emphasizes that reviews such as this can only be as good as the studies they summarise and it is important to note that a high proportion of the included studies have a substantial risk of bias.
"It is also important to recognize that, while this review reports high preterm birth rates, a number of women affected by Covid-19 in pregnancy are still pregnant, and thus are not included in the study data. This may make preterm birth rates appear artificially high. Preterm birth rates are likely to be lower once all women have given birth and their information is included. Nevertheless, some pregnant women affected by Covid-19 may have a subsequent preterm birth, and preventing infection remains essential. Pregnant women should thus continue to pay attention to hand washing and social distancing measures to reduce their risk of coronavirus," recommends Knight.
Evidence currently suggests that people who are non-White, are older, who are overweight and/or have a pre-existing medical condition, are more vulnerable to severe disease due to Covid-19. According to the new findings, pregnant women with Covid-19, who have pre-existing medical conditions, such as diabetes or chronic high blood pressure, or those who are older or overweight, are also more likely to suffer severe health complications due to coronavirus.
"Maternal risk factors associated with severe Covid-19 were increasing age, high body mass index, chronic high blood pressure, and pre-existing diabetes. Pre-existing maternal comorbidity was associated with admission to an intensive care unit and the need for invasive ventilation. These findings underline the need for pregnant women and recently pregnant women to take all precautions to avoid COVID-19 disease, in particular, if they have underlying conditions,” says the team.
Researchers point to some study limitations that may have affected their results, including differences in study size, design, and definitions of symptoms, tests and outcomes. However, strengths include the large sample size and robust search methods to minimize the risk of missing studies and duplicate data, they explain.
Implications for healthcare
According to the researchers, healthcare professionals should be aware that pregnant women with Covid-19 and their newborn babies might need access to intensive care and specialist baby care facilities. This is particularly true for pregnant women with Covid-19 alongside other underlying medical conditions. The experts suggest that mothers with pre-existing comorbidities will need to be considered as a high-risk group for Covid-19, along with those who are obese and of older age.
"Clinicians will need to balance the need for regular multidisciplinary antenatal care to manage women with pre-existing comorbidities against unnecessary exposure to the virus, through virtual clinic appointments when possible. Pregnant women with Covid-19 before term gestation might need to be managed in a unit with facilities to care for preterm neonates," the findings state.
The team believes it is crucial to stress that whether or not a woman has Covid-19, her right to a positive pregnancy and childbirth experience must be ensured. "It is also important to recognize the increased stress and anxiety caused by Covid-19, which may be particularly felt by pregnant women, recently-pregnant women, and their partners, children, and families; healthcare providers have a role in responding to pregnant women in an appropriate and compassionate way," suggest authors.