Are pregnant women at a higher risk of death with COVID-19, and if so, what confers this increased risk?
A recent research letter published on the preprint server medRxiv* in June 2020 evaluates the risk factors that may lead to higher mortality in pregnant women with COVID-19 in middle-income countries.
The current pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is more deadly to the elderly and the sick, particularly those with underlying chronic inflammatory conditions such as cardiovascular disease, obesity, and diabetes. The mortality in the elderly population segment is many times higher than that in the young, depending on the age bracket.
Even in countries with a high prevalence of COVID-19, a survey of mortality data shows that women are at all ages less likely to fall sick with the infection, to develop a severe infection, or to die, than men. This has suggested that pregnant women are also not more vulnerable to infection or complications than the general population. However, not much is known about how other conditions affect mortality in this subgroup.
The current paper deals with the effect of other medical conditions, or of advancing maternal age, on maternal mortality, in Mexico. Mexico had over 10,000 COVID-19 linked deaths among about 94,000 cases at the time of the study. This made it Number 2 in terms of mortality due to the pandemic, among Latin American countries, and third in terms of the number of confirmed cases.
Designed as a prospective study, the research makes use of data retrieved from the epidemiological survey data for viral respiratory diseases.
The surveillance covers 475 units with over 135,000 individuals, including 1,241 pregnant women, being tested for viral respiratory disease. All pregnant women who tested positive by RT-PCR for the SARS-CoV-2 between January 1 and May 11, 2020, were included in the study, for a total of 224 participants.
The researchers also examined the data on other medical conditions in this subgroup, like pregestational diabetes, chronic hypertension, chronic obstructive pulmonary disease (COPD), asthma, immunosuppression, obesity, chronic kidney disease, and smoking.
Of the 224 pregnant women with COVID-19, 25 had severe disease, with 7 deaths. This corresponds to just above 3% of the cohort, occurring at a median of 9 days from the earliest symptoms.
Of the total deaths, 5/7 deaths occurred in women with other illnesses complicating pregnancy. The pregnant women who died were likely to be older, at a median of 37 years vs. 29 years for the general cohort. Overall, women over 35 years had almost 8 times higher odds of dying compared to those below this age.
While about a third of all women in this group had other illnesses, the percentage of pregnant COVID-19 cases with comorbidities went up to over 71% of those who died, conferring 6-fold higher odds of death in this subgroup. The highest odds of death were in those with diabetes (40-fold). Other conditions were not significantly associated with a higher risk of death.
Increased Mortality and Risk Factors
While advanced maternal age was associated with higher mortality risk in this study, diabetes was found to be the single most significant risk factor for death among pregnant women with COVID-19. The link between elderly maternal age and death is explained in part by the increasing incidence of lifestyle and non-communicable diseases in this age group, which is an almost universal phenomenon.
Over the last few years, rapid economic and cultural changes have occurred globally, which has led to lifestyle changes in many low- and middle-income countries (LMIC). This is reflected in the increasing number of diabetic and obese individuals across the population spectrum, including pregnant women.
This trend is also partly responsible for the higher rate of complications and deaths among the elderly population with COVID-19. It is, therefore, a matter of public health priority to bring down the incidence of obesity and diabetes in LMIC.
The low number of deaths limits the current study as a result of which much cannot be inferred about the underlying risk factors. However, there is a definite significant association of higher mortality in pregnant women infected with SARS-CoV-19, with diabetes and advanced age. This should prompt health policy planners to evolve protective measures for this highly susceptible population.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.