We have presented the MMR estimates increase during the pandemic and provided an overview of the magnitude of COVID-19 confirmed and unconfirmed maternal mortality cases. In addition, when analyzing pregnant women hospitalized due to COVID-19, we have identified particular conditions that increased vulnerability for adverse outcomes.
Of the 1056 maternal deaths recorded in Mexico in 1 year, COVID-19 was to some extent associated with 27.5% of maternal deaths that occurred. During this period, it was the leading cause of maternal death in the country. Before the advent of COVID-19, maternal mortality’s leading causes were obstetric hemorrhages and hypertensive diseases [11, 12]. This nationwide MMR was surpassed in twelve states; the most dramatic increases were observed in Guerrero, Morelos, and Chihuahua.
In the present study, the Maternal Mortality Ratio due to COVID-19 was 13.6 for confirmed and 2.4 for unconfirmed cases, while lethality among hospitalized pregnant patients was 2.8%. These results are far above the projected panorama of more than COVID-19-related maternal deaths for the United States of America [13]. A systematic review of thirteen studies from three countries (China, the United States of America, and Italy) found mortality among pregnant women with COVID-19 to be zero [14]. In other studies, maternal mortality is not assessed, for instance, in a metanalysis review of adverse pregnancy outcomes among pregnant women with COVID-19 in China and European countries [15]. The present results suggest that in Mexico, COVID-19 among pregnant women may have an unprecedented fatality rate.
Access to proper and timely care during pregnancy can dramatically affect outcomes. Intensive care unit (ICU) access is particularly vital in acute COVID-19 cases, but this can vary widely between different countries. In a study mentioned above, [14] ICU admissions of pregnant women with COVID-19 in China, the United States of America, and Italy averaged 3%. In a study of pregnant women with COVID-19 (N = 637; 1.6% mortality) hospitalized in China, ICU admission was 9.6% [16], higher than the present study’s 1.7% ICU admission rate. The second cause of maternal mortality in Mexico during the study was hypertensive diseases, proteinuria in pregnancy, puerperium (15.1%), and obstetric hemorrhage (13.8%). These disorders may be unrelated to COVID-19 infection per se. Still, the conditions prevailing in Mexico during the pandemic (e.g., long-term confinement and its immediate social correlates) may be propitious for allowing treatable adverse conditions to end in maternal mortality. This situation warrants further analysis since adequate prenatal control helps identify women with risk factors for developing obstetric hemorrhages, such as clinical diagnosis of the accrete placenta. However, the massive increase in demand for health services caused by the COVID-19 pandemic in Mexico has severely taxed the public health system’s capacity. The need for more ICU wards and additional healthcare personnel to treat the influx of COVID-19 cases resulted in the implementation of strategies such as suspension of chronic and non-urgent care in hospitals [17,18,19,20] and giving ICU priority to COVID-19 cases.
Maternal mortality is an indicator of a country’s development level. It evidences poverty and social exclusion, and in 2015, WHO reported that 303,000 women died due to complications during pregnancy or birth, which translates to an MMR of 216 deaths per 100,000 live births. Of these deaths, 99% occurred in developing countries, and most were preventable [20].
In the current environment, this is unattainable in Mexico, which is particularly alarming compared to the 39 deaths per 100,000 live births from all causes of maternal mortality nationwide from 2005 to 2014 [21].
Maternal mortality has increased in Mexico due to COVID-19, specifically in severe cases manifesting ARDS and/or pneumonia. Complications were more probable when the cardiorespiratory system was affected. The particular vulnerability of pregnant women to SARS-CoV-2 can be explained by the probable involvement of the pathophysiological pathway involving T-helper system response and th1/th2 balance, as described for the Influenza A virus [22]. Individual lifestyle may also have some effect on case severity. The way to address this threat is for maternal health care professionals to closely monitor patients with COVID-19. Their clinical manifestations need to be controlled using a preventive approach focusing on those with underlying chronic conditions, which documents signs and symptoms of severity as a way of deciding if and when ambulatory or in-hospital treatment is indicated. Procedures need to be developed based on available resources and existing guidelines, and patients need to be aware of them [23, 24].
As shown in the present results, not all maternal deaths in Mexico are directly related to COVID-19 infection but rather to uncontrolled conditions during pregnancy due to the limited healthcare availability. Social distancing and limited mobility are crucial to reducing SARS-CoV-2 transmission. Nonetheless, healthcare during pregnancy is also essential to ensure healthy pregnancies. In-person medical attention can be reinforced during this pandemic by telemedicine or web-based strategies to monitor and detect any pregnancy or COVID-19 related complication and guide decision-making, including suitable transportation to specialized health centers [25].
Unintended pregnancies are commonly associated with late or no prenatal care in Mexico [26], and these pregnancies may be more frequent at both extremes of the reproductive age span (< 18 or > 38 years). During the pandemic, unintended pregnancies can be complicated by confinement and consequent delays in or omission of early medical attention. A recent estimate is that 145,719 births in Mexico in 2020 were from unintended pregnancies, mainly in response to the social behaviors derived from confinement and the barriers to adequate healthcare and family planning created by the pandemic [27]. For instance, the Pan-American Health Organization (PAHO) recently called on member states to intensify and improve access to prenatal care services and preventive measures to reduce COVID-19 morbidity and mortality. Furthermore, the PAHO asked its members to renew their commitment to reducing maternal and perinatal mortality even more than pre-pandemic [4], implying an urgent need for preventive strategies at all levels.
Limitations
The retrospective design applied in the study poses limitations such as the inability to add relevant information (e.g., more specific clinical manifestations, pregnancy duration, or fetal/neonatal health status). Such information could be relevant when explaining Mexico’s maternal mortality panorama during the current pandemic. Data on pre-pregnancy BMI > 30 was collected at the moment of COVID-19 diagnosis. The patient’s social, economic, and reproductive determinants could not be retrieved for the present study because these data are not available until the annual datasets are completed and published. Furthermore, it was not within the study scope to identify increases in mortality due to COVID-19 because it did contemplate access to women with high-risk pregnancies in healthcare facilities.