Respiratory complications of pregnancy

Increased risk of severe COVID-19 in pregnancy in a multicenter propensity score-matched study

OBJECTIVES

To explore the association between COVID-19 severity and pregnancy using measures such as COVID-19 ordinal scale severity score, hospitalization, intensive care unit (ICU) admission, oxygen supplementation, invasive mechanical ventilation, and death.

METHODS

We conducted a retrospective, multicenter cohort study to understand the association between COVID-19 severity and pregnancy. We reviewed consecutive charts of adult females, ages 18-45, with laboratory testing for SARS-CoV-2 infection between March 1, 2020, and August 31, 2020. Cases were patients diagnosed with COVID-19 during pregnancy, whereas controls were not pregnant at the time of COVID-19 diagnosis. Primary endpoints were the COVID-19 severity score at presentation (within four hours) and the nadir of the clinical course. The secondary endpoints were the proportion of patients requiring hospitalization, ICU admission, oxygen supplementation, invasive mechanical ventilation, and death.

RESULTS

A higher proportion of pregnant women had moderate to severe COVID-19 disease at the nadir of the clinical course than non-pregnant women (25 vs. 16.1 %, p=0.04, respectively). There was a higher rate of hospitalization (25.6 vs. 17.2 %), ICU admission (8.9 vs. 4.4 %), need for vasoactive substances (5.0 vs. 2.8 %), and invasive mechanical ventilation (5.6 vs. 2.8 %) in the pregnant cohort. These differences were not significant after applying propensity score matching.We found a high rate of pregnancy complications in our population (40.7 %). The most worrisome is the rate of hypertensive disorders of pregnancy (20.1 %).

CONCLUSIONS

In our propensity score-matched study, COVID-19 in pregnancy is associated with an increased risk of disease severity and pregnancy complications.

A Review of Coronavirus Disease 2019 in Pregnancy

Pregnancy is an independent risk factor for morbidity and mortality in coronavirus disease 2019 (COVID-19) with increased rates of operative delivery, intensive care unit admission, and mechanical ventilation as well as a possible increased risk of death, independent of other risk factors, compared with nonpregnant women with COVID-19. Furthermore, pregnancy outcomes are worse in those with COVID-19 with increased risk for preeclampsia, venous thromboembolism, preterm birth, miscarriage, and stillbirth compared with pregnant women without COVID-19. Importantly, pregnant women of nonwhite ethnicity appear to be at greater risk of severe COVID-19, necessitating improved access to care and closer monitoring in these women. The management of COVID-19 in pregnancy is largely similar to that in nonpregnant people; however, there is an important emphasis on multidisciplinary team involvement to ensure favorable outcomes in both mother and baby. Similarly, vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is safe in pregnancy and improves maternal and neonatal outcomes.

The Relationship Between Delivery and the PaO2/FiO2 ratio in COVID-19: A Cohort Study

OBJECTIVE

To study the effect of delivery on the pO₂ /FiO₂ ratio (P/F ratio) in patients with COVID-19-related acute respiratory distress syndrome (ARDS) and to compare characteristics between delivered and undelivered pregnant patients with COVID-19.

DESIGN

Retrospective cohort.

SETTING

Four hospitals in Houston, Texas.

POPULATION

Pregnant patients admitted to the hospital for COVID-19.

METHODS

Among patients with ARDS who were delivered during their hospitalization for COVID-19, linear mixed models were used to investigate time trends before and after delivery of the P/F ratio. Patient characteristics were compared between patients delivered during their hospitalization for COVID-19 and those discharged undelivered.

MAIN OUTCOME MEASURES

The P/F ratio, age, gestational age, length of stay, and severity of illness,.

RESULTS

Between May 4, 2020 and July 26, 2020, 61 pregnant patients were admitted for COVID-19. Baseline characteristics were similar between the study groups. Delivery occurred in 21 (34%) of patients during their hospitalization for COIVD-19. Delivered patients had more severe disease and were admitted at a later gestational age than patients not delivered. Ten of these 21 patients (48%) were delivered preterm, and of these, six were delivered due to complications of COVID-19 and four were delivered for obstetric indications. In patients with ARDS who were delivered (n=17), the P/F ratio had a negative slope that improved after delivery.

CONCLUSIONS

COVID-19-related ARDS in pregnancy requires multidisciplinary care and individualized decision-making, but delivery slows the deterioration of the P/F ratio in these patients.

Current Challenges in Diagnosis of Venous Thromboembolism

In patients with suspected venous thromboembolism, the goal is to accurately and rapidly identify those with and without thrombosis. Failure to diagnose venous thromboembolism (VTE) can lead to fatal pulmonary embolism (PE), and unnecessary anticoagulation can cause avoidable bleeding. The adoption of a structured approach to VTE diagnosis, that includes clinical prediction rules, D-dimer testing and non-invasive imaging modalities, has enabled rapid, cost-effective and accurate VTE diagnosis, but problems still persist. First, with increased reliance on imaging and widespread use of sensitive multidetector computed tomography (CT) scanners, there is a potential for overdiagnosis of VTE. Second, the optimal strategy for diagnosing recurrent leg deep venous thrombosis remains unclear as is that for venous thrombosis at unusual sites. Third, the conventional diagnostic approach is inefficient in that it is unable to exclude VTE in high-risk patients. In this review, we outline pragmatic approaches for the clinician faced with difficult VTE diagnostic cases. In addition to discussing the principles of the current diagnostic framework, we explore the diagnostic approach to recurrent VTE, isolated distal deep-vein thrombosis (DVT), pregnancy associated VTE, subsegmental PE, and VTE diagnosis in complex medical patients (including those with impaired renal function).

Alkaline phosphatase protects lipopolysaccharide-induced early pregnancy defects in mice

Excessive cytokine inflammatory response due to chronic or superphysiological level of microbial infection during pregnancy leads to pregnancy complications such as early pregnancy defects/loss and preterm birth. Bacterial toxin lipopolysaccharide (LPS), long recognized as a potent proinflammatory mediator, has been identified as a risk factor for pregnancy complications. Alkaline phosphatase (AP) isozymes have been shown to detoxify LPS by dephosphorylation. In this study, we examined the role of alkaline phosphatase (AP) in mitigating LPS-induced early pregnancy complications in mice. We found that 1) the uterus prior to implantation and implantation sites following embryo implantation produce LPS recognition and dephosphorylation molecules TLR4 and tissue non-specific AP (TNAP) isozyme, respectively; 2) uterine TNAP isozyme dephosphorylates LPS at its sites of production; 3) while LPS administration following embryo implantation elicits proinflammatory cytokine mRNA levels at the embryo implantation sites (EISs) and causes early pregnancy loss, dephosphorylated LPS neither triggers proinflammatory cytokine mRNA levels at the EISs nor induces pregnancy complications; 4) AP isozyme supplementation to accelerate LPS detoxification attenuates LPS-induced pregnancy complications following embryo implantation. These findings suggest that a LPS dephosphorylation strategy using AP isozyme may have a unique therapeutic potential to mitigate LPS- or Gram-negative bacteria-induced pregnancy complications in at-risk women.

Prenatal care providers and influenza prevention and treatment: lessons from the field

To better understand the knowledge, attitudes, and behaviors of providers regarding influenza infection and vaccination in pregnancy, fourteen focus groups were conducted among 92 providers in Atlanta, GA; Dallas, TX; and Portland, OR in late 2009. NVivo 8.0 was used for analysis. Most providers had no experience with pregnant women severely affected by influenza. Many perceived the 2009 H1N1 pandemic to be limited and mild. Providers knew that pregnant women should receive the 2009 H1N1 vaccine and reported plans to vaccinate more patients than the previous season. Most knew CDC guidelines for antiviral treatment and prophylaxis, but some reported hesitancy with presumptive treatment. Although awareness of influenza's potential to cause severe illness in pregnant women was observed, providers' experience and comfort with influenza prevention and treatment was suboptimal. Sustained efforts to educate prenatal care providers about influenza in pregnancy through trusted channels are critical.

Pulmonary CT angiography protocol adapted to the hemodynamic effects of pregnancy

OBJECTIVE

The purpose of this study was to compare the image quality of a standard pulmonary CT angiography (CTA) protocol with a pulmonary CTA protocol optimized for use in pregnant patients with suspected pulmonary embolism (PE).

MATERIALS AND METHODS

Forty-five consecutive pregnant patients with suspected PE were retrospectively included in the study: 25 patients (group A) underwent standard-protocol pulmonary CTA and 20 patients (group B) were imaged using a protocol modified for pregnancy. The modified protocol used a shallow inspiration breath-hold and a high concentration, high rate of injection, and high volume of contrast material. Objective image quality and subjective image quality were evaluated by measuring pulmonary arterial enhancement, determining whether there was transient interruption of the contrast bolus by unopacified blood from the inferior vena cava (IVC), and assessing diagnostic adequacy.

RESULTS

Objective and subjective image quality were significantly better for group B-that is, for the group who underwent the CTA protocol optimized for pregnancy. Mean pulmonary arterial enhancement and the percentage of studies characterized as adequate for diagnosis were higher in group B than in group A: 321 ± 148 HU (SD) versus 178 ± 67 HU (p = 0.0001) and 90% versus 64% (p = 0.05), respectively. Transient interruption of contrast material by unopacified blood from the IVC was observed more frequently in group A (39%) than in group B (10%) (p = 0.05).

CONCLUSION

A pulmonary CTA protocol optimized for pregnancy significantly improved image quality by increasing pulmonary arterial opacification, improving diagnostic adequacy, and decreasing transient interruption of the contrast bolus by unopacified blood from the IVC.

Unusual association of ST-T abnormalities, myocarditis and cardiomyopathy with H1N1 influenza in pregnancy: two case reports and review of the literature

Introduction

Myocarditis is rarely reported as an extra-pulmonary manifestation of influenza while pregnancy is a rare cause of cardiomyopathy. Pregnancy was identified as a major risk factor for increased mortality and morbidity due to H₁N₁ influenza in the pandemic of 2009 to 2010. However, to the best of our knowledge there are no previous reports in the literature linking H₁N₁ with myocarditis in pregnancy.

Case presentation

We report the cases of two pregnant Caucasian women (aged 29 and 30), with no pre-existing illness, presenting with respiratory manifestations of H₁N₁ influenza virus infection in their third trimester. Both women developed evidence of myocarditis. One woman developed acute respiratory distress syndrome, almost reaching the point of requiring extra-corporeal membrane oxygenation, and subsequently developed persistent cardiomyopathy; the other recovered without any long-term consequence.

Conclusions

While it is not possible to ascertain retrospectively if myocarditis was caused by either infection with H₁N₁ virus or as a result of pregnancy (in the absence of endomyocardial biopsies), the significant association with myocardial involvement in both women demonstrates the increased risk of exposure to H₁N₁ influenza virus in pregnant women. This highlights the need for health care providers to increase awareness amongst caregivers to target this 'at risk' group aggressively with vaccination and prompt treatment.

Safety of oseltamivir in pregnancy: a review of preclinical and clinical data

Pregnant women with influenza are at increased risk of morbidity, particularly due to respiratory complications. A high excess mortality rate among pregnant women has been observed in previous influenza pandemics and healthcare agencies have provided recommendations on the use of oseltamivir to treat pregnant women who are infected with the pandemic (H1N1) 2009 virus. This article reviews pre-clinical and clinical data to assess the safety of oseltamivir administered during pregnancy, in the context of the effects of influenza on adverse pregnancy outcomes and fetal malformations. The effects of influenza during pregnancy, whether mediated directly by the virus or by fever or other events secondary to the underlying infection, are not yet well understood, but some data indicate an increased risk of birth defects in women infected with influenza during the first trimester. Animal and toxicology studies do not suggest that clinically effective dosages of oseltamivir have the potential to produce adverse effects on fetal development. Additionally, transplacental transfer of the drug and its active metabolite was very limited and not detectable at normal therapeutic doses in an ex vivo human placenta model. To investigate the safety of oseltamivir in pregnancy, the Roche oseltamivir safety database was searched for all exposures to oseltamivir during pregnancy in the 9 years up to 14 December 2008. In addition, a search of the literature was carried out. Of 232 maternal exposures to oseltamivir in the Roche database, pregnancy outcomes were known for 115 of these exposures. The incidence of adverse pregnancy outcomes was as follows: spontaneous abortions 6.1% (7/115), therapeutic abortions 11.3% (13/115) and pre-term deliveries 2.1% (2/94 live births), values that are not higher than background incidence rates. Fetal outcomes were known in 100 of the 232 exposures. For the nine cases of birth defect that were reported, the timing of oseltamivir exposure in relation to the sensitive period for inducing the birth defect was analysed. Two cases of ventricular septal defect, a more common birth defect, and one case of anophthalmos, an uncommon birth defect, were consistent with exposure to oseltamivir during the sensitive period for these birth defects. For other birth defects, there was either no exposure to oseltamivir during the sensitive period for the defect or insufficient information for assessment. These findings were consistent with other reports in the published literature, including a series of 79 Japanese women exposed to oseltamivir during the first trimester. Together with the other evidence reviewed herein, review of the company safety database suggests that oseltamivir is unlikely to cause adverse pregnancy or fetal outcomes, but available data are limited. Clinicians who use oseltamivir in pregnant women should consider the available safety information, the pathogenicity of the circulating influenza virus strain, the woman's general health and the guidance provided by health authorities. Roche will continue to monitor all reports of oseltamivir use during pregnancy.

Is routine influenza immunization warranted in early pregnancy?

Routine influenza immunization is recommended for select groups because of their higher risk of serious influenza outcomes. Based on that benefit-risk framework, we assessed whether routine administration of trivalent inactivated influenza vaccine (TIV) is warranted in pregnancy, beginning in 1st trimester. Higher maternal mortality due to influenza was extensively described during the 1918 and 1957 pandemics, but epidemiologic evidence thereafter is limited to case reports and a single ecologic analysis during a single season. Significantly elevated rates of hospitalization have been reported with seasonal influenza beginning in 1st trimester among women with select comorbidities and during the 2nd half of normal pregnancy. TIV protection against serious outcomes in pregnant women has not yet been shown. Although harm has also not been shown, sample size to date is insufficient to assert TIV safety in 1st trimester. Benefit-risk analysis suggests influenza immunization may be warranted at any stage of pregnancy during certain pandemics and annually among women with select comorbidities. TIV may also be warranted to protect women against influenza-related hospitalization during the 2nd half of normal pregnancy. Evidence is otherwise insufficient to recommend routine TIV as the standard of practice for all healthy women beginning in early pregnancy.

Effects of Bacillus cereus var. toyoi on immune parameters of pregnant sows

Changing immune parameters during pregnancy have previously been reported in humans and cattle, and have been suggested to contribute to increased susceptibility to infections. However, data regarding immune parameters during pregnancy in sows are rare. In this study, we investigated the peripartal immune status of sows using phenotypical (FACS analysis) as well as functional (proliferation assays, cytokine analysis) parameters of peripheral blood mononuclear cells (PBMCs) in pregnant sows. In previous studies, we reported a modulation of the immune system after feed supplementation of the probiotic Bacillus cereus var. toyoi in piglets [Schierack, P., Wieler, L.H., Taras, D., Herwig, V., Tachu, B., Hlinak, A., Schmidt, M.F., Scharek, L., 2007. Bacillus cereus var. toyoi enhanced systemic immune response in piglets. Vet. Immunol. Immunopathol. 118, 1-11]. Here, we extended these previous studies to include investigations of possible probiotic effects on the peripartal immune status of sows and their reproductivity. We show that immune parameters of sows change during pregnancy, the proliferative response of PBMCs to several bacterial antigens in control animals decreased from days 90 to 30 ante partum. Relative numbers (%) of CD3+CD8+, CD4+, cytotoxic T, CD14+ and CD21+ cells were reduced compared to non-pregnant sows. In contrast, the proliferative response of PBMCs of probiotic-treated sows increased during pregnancy. Bacterial antigens primarily stimulated the proliferation of naïve CD21+ cells and the relative CD21+ cell numbers were elevated in the probiotic group in the absence of effects on other immune cell populations. The clinical and microbial status of both control and probiotic sows was similar, excluding pre-existing health problems or infections as responsible for the immunological changes, and feed supplementation also had no significant effects on reproductivity. The results suggest that the probiotic B. cereus var. toyoi can alter the proliferative response of lymphocytes and affects the immune cell population ratios of pregnant sows. How and to what extent this may affect health and reproductivity should be the focus of further studies.

Influenza-attributed hospitalization rates among pregnant women in Canada 1994-2000

BACKGROUND

Although it is recommended that pregnant women at risk for influenza complications receive influenza vaccine, it is not clear if healthy pregnant women are at increased risk for adverse outcomes. We aimed to estimate the rate of hospitalization attributable to influenza for healthy pregnant women and for those with known co-morbidities.

METHODS

Hospital admission records of women admitted from 1994 to 2000 with a respiratory condition during pregnancy were extracted from the hospitalization database (Canadian Institute of Health Information). Admissions for childbirth were excluded. Weekly admissions, stratified by the presence of co-morbid conditions, were modelled as a function of viral activity, seasonality, trend, and holiday effects using Poisson regression with proxies for influenza and other viral activity developed previously for similar age-specific models of influenza-attributed hospital admissions.

RESULTS

Approximately 300 hospitalizations of pregnant women per year were attributed to influenza, of which 140 were in women with co-morbidities. This hospitalization rate corresponds to 150 (95% CI 140-170) hospitalizations per 100,000 pregnant women per year. An estimated 1 in 1000 healthy pregnant women were hospitalized due to influenza per year. Asthma was the most important risk factor, accounting for an estimated 450 (95% CI 300-600) admissions per 100,000 pregnant women. Admission rates in pregnant women were relatively constant across multiple influenza seasons of varying severity among older adults. During the four weeks of peak influenza activity, 60% of respiratory-related admissions of otherwise healthy pregnant women could be attributed to influenza.

CONCLUSION

Healthy pregnant Canadian women have consistently higher rates of hospital admission attributable to influenza infection than their non-pregnant peers. The admission rate for healthy pregnant women corresponds to the rate for men and women aged 65 to 69 years, which suggests that this population may benefit from annual influenza immunization.

Community influenza activity and risk of acute influenza-like illness episodes among healthy unvaccinated pregnant and postpartum women

This study investigated the relation between weekly levels of influenza activity and the risk of acute influenza-like illness episodes among 8,323 healthy pregnant and postpartum women enrolled in a Puget Sound region, Washington, health maintenance organization, Group Health Cooperative, between June 1991 and December 1997. The authors classified weeks between October and May for isolate activity level based on surveillance data for influenza, respiratory syncytial virus, parainfluenza, and adenovirus infection. Influenza-like illness episodes were identified from medical encounters assigned a diagnostic code consistent with a symptomatic influenza infection. The authors compared the occurrence of influenza-like illness episodes within each pregnancy stage for periods with varying levels of influenza isolate detection in the community. Repeated-measures logistic regression methods accounted for time-dependent factors. The adjusted strength of association between influenza exposure and influenza-like illness episodes increased as the pregnancy stage progressed (first trimester odds ratio = 1.12, 95% confidence interval: 0.79, 1.59; second trimester odds ratio = 1.30, 95% confidence interval: 0.97, 1.73; third trimester odds ratio = 1.84, 95% confidence interval: 1.31, 2.59; postpartum period odds ratio = 2.28, 95% confidence interval: 1.42, 3.68). Pregnancy stage modified the association between influenza activity and influenza-like illness episodes. Findings estimate that 20-43 pregnant/postpartum women would need to be vaccinated with an 80% effective vaccine to prevent one influenza-like illness episode.

Pneumonia in pregnancy

OBJECTIVE

Historically, pneumonia during pregnancy has been associated with increased morbidity and mortality compared with nonpregnant women. The goal of this article is to review current literature describing pneumonia in pregnancy. This review will identify maternal risk factors, potential complications, and prenatal outcomes associated with pneumonia and describe the contemporary management of the varied causes of pneumonia in pregnancy.

RESULTS

Coexisting maternal disease, including asthma and anemia, increase the risk of contracting pneumonia in pregnancy. Neonatal effects of pneumonia in pregnancy include low birth weight and increased risk of preterm birth, and serious maternal complications include respiratory failure. Community-acquired pneumonia is the most common form of pneumonia in pregnancy, with Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae accounting for most identified bacterial organisms. Beta-lactam and macrolide antibiotics are considered safe in pregnancy and are effective for most community-acquired pneumonia in pregnancy. Viral respiratory infections, including varicella, influenza, and severe acute respiratory syndrome, can be associated with maternal pneumonia. Current antiviral and respiratory therapies can reduce maternal morbidity and mortality from viral pneumonia. Influenza vaccination can reduce the prevalence of respiratory hospitalizations among pregnant women during influenza season. Pneumocystis pneumonia continues to carry significant maternal risk to an immunocompromised population. Prevention and treatment of Pneumocystis pneumonia with trimethoprim/sulfamethoxazole is effective in reducing this risk.

CONCLUSIONS

Prompt diagnosis and treatment with contemporary antimicrobial therapy and intensive care unit management of respiratory compromise has reduced the maternal morbidity and mortality due to pneumonia in pregnancy. Prevention with vaccination in at-risk populations may reduce the prevalence and severity of pneumonia in pregnant women.

Pulmonary complications of pregnancy

Pregnancy induces significant physiologic stresses on the pulmonary and cardiovascular systems that may precipitate respiratory compromise. In addition, certain disease states that are unique to the pregnant woman, such as amniotic fluid emboli syndrome, may be associated with respiratory failure. The physiologic changes that affect the pregnant woman are reviewed. Pregnancy-related conditions are discussed as well as how common diseases, such as the acute respiratory distress syndrome, asthma, pneumonia, and AIDS,have to be approached when balancing the needs of the fetus with maternal well-being.

Embolism during pregnancy: thrombus, air, and amniotic fluid

Pulmonary embolism is the primary cause of acute respiratory decompensation during pregnancy. Regardless of the nature of the embolism, a high index of suspicion, early diagnosis, and aggressive resuscitation need to be instituted to achieve a successful maternal and fetal outcome. Several clinical characteristics will assist practitioners to distinguish among the different forms of embolism and to institute specific measures of treatment.