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Infection during pregnancy: Continued challenges into the 21st century

Since the first evidence of life on earth approximately 3.7 billion years ago, there has been an open, yet close, interaction between all kinds of living species. The fact that humans carry about 9% of viral DNA in our genome, which had been vectored by retroviruses about 70–90 million years ago, illustrates the great power of invisible intruders on the one hand, and both openness and vulnerability of humans on the other. In 1980, smallpox was declared by WHO to be eradicated from the world in perhaps the single most important achievement in public health. Polio was being tamed through an aggressive vaccine programme and the public health community set their sights on eradicating this disease as well. Swine flu had just been avoided, and Legionnaire’s disease deciphered. Syphilis had virtually disappeared. New, more powerful antibiotics were being introduced, and no infectious disease appeared to be immune from the eventual development of effective vaccines or antibiotics. The medical field felt invincible when it came to infectious diseases. We were wrong. We subsequently entered a new era of infection-related public health crises. First came the HIV epidemic, followed by an international recurrence of congenital syphilis. Then came the Severe Acquired Respiratory Syndrome (SARS) outbreak in 2003, H1N1 influenza in 2008–2009, recurrent episodes of Ebola Virus infection, the appearance of Zika virus in 2018 with its devastating fetal and neonatal sequela, and, beginning in 2019, the SARS-CoV-2 viral pandemic. Concurrent research advances in the identification, isolation and genetic sequencing of causative agents of new infectious diseases led to the sequencing of the SARS-CoV-2 virus within weeks of its initial appearance and creation of safe and effective vaccines in less than a year. Despite these impressive accomplishments, clearly infectious diseases cannot be conquered. A new pandemic, potentially more deadly than prior ones, seems to now appear every 3–5 years. While mortality from infectious diseases had declined precipitously from 1900 to 1980, this trend has been reversed over the past 40 years. Mortality trends undoubtedly will further increase with the current SARS-COV 2 pandemic. In this special theme issue of BJOG, we focus on infectious diseases that are of particular concern to pregnant women and their neonates. Our intent is to highlight new cutting-edge research in the identification of specific infections in pregnancy, their pathogenesis, and means of prevention and effective treatment. We also sought to highlight the critical need of continued research to decipher how a more thorough understanding of the pathophysiology of infection in pregnancy can lead to improvements in maternal, fetal and neonatal outcomes. The unique physiology of pregnancy, with multiple immunological, hormonal, nutritional and behavioural alterations, results in altered susceptible to pathogenic agents, often leading to increased morbidity and maternal and fetal mortality. Given the overriding concerns of clinicians, researchers and the general public in response to the current SARS-CoV-2 pandemic, a major focus of this issue is on articles highlighting the latest findings of this infection in pregnant versus non-pregnant women and its consequences for mother and baby. The development of RNA vaccines to treat the SARS-CoV-2 outbreak and their mechanism of action is described along with studies detailing their efficacy in pregnant women. Concerns about vaccine hesitancy, currently still an unfortunate controversy in many countries, is also discussed. Not wishing to neglect other viral infections highly relevant to pregnant women, this issue also presents studies related to HIV, hepatitis B, hepatitis C, and cytomegalovirus maternal infection. In addition, in the area of bacterial infections a diverse group of articles are presented dealing with consequences of maternal mycoplasma infections, breast implants and postpartum mastitis, causes of endometritis in women undergoing in vitro fertilisation and the value of immunisation against group B streptococcus. Lastly, an in-depth review is presented detailing the potential value of analysis of regions of the female genital tract at the single cell level to help resolve the current controversy of which regions contain microorganisms and which are sterile. We hope that becoming familiar with the articles presented in this issue will improve the comprehension of clinical investigators, enabling them to better transmit the latest and most accurate information to their patients. Concurrently, an improved understanding of outstanding unresolved issues will hopefully motivate researchers to focus on these issues that are so critical to maternal and neonatal well-being. As long as there is life on earth, there will be this interplay between bacteria, viruses and living beings. Given this, we cannot foresee how newly emerging or re-emerging infections will threaten us in the future.