The changing landscape of SARS-CoV-2: Implications for the maternal-infant dyad.

The COVID-19 pandemic represents the greatest challenge to date faced by the medical community in the 21st century. The rate of rapid dissemination, magnitude of viral contagiousness, person to person transmission at an asymptomatic phase of illness pose a unique and dangerous challenge for all patients, including neonatal and obstetric patients. Although scientific understanding of the pathophysiology of the disease, nature of transmission, and efficacy of mitigation strategies is growing, neither a cure or vaccine have been developed. While COVID-19 is primarily a disease of older patients, infection is now seen across all age demographics with reports of illness in pregnant patients and infants. Altered hormone status and predominance of Th-2 immune helper cells may result in increased predisposition to SARS-CoV-2. Case reports of pregnant patients demonstrate a clinical presentation comparable to non-pregnant adults, but evidence of vertical transmission to the fetus is controversial. Neonatal reports demonstrate an inconsistent and non-specific phenotype, and it is often difficult to separate COVID-19 from the underlying conditions of prematurity or bacterial infection. The development of international registries to enable risk profiling of COVID-19 positive pregnant mothers and/or their offspring may facilitate the development of enhanced mitigation strategies, medical treatments and effective vaccinations.

Prematurity: present and future.

The study of preterm labor and prematurity has undergone a major transformation in its approach from an inevitable part of obstetrics with few answers to one in which science has led to knowledge and clinical intervention. Despite these advancements, understanding of preterm labor and prevention of prematurity is still limited. In the current review, we begin the discussion with fetal viability, first from a historical perspective and then from the understanding of this issue from a prospective of various professional organizations. We then present the scope of the problem of preterm birth from various countries including the discrepancy between the US and Europe. We continue with updates on extreme prematurity and outcomes with two longitudinal studies from the past 2 years. We further review available interventions for prematurity and discuss the use of antenatal corticosteroids. First, we examine their use in the context of professional recommendations and then examine the trajectory of their continued use in the late preterm period. We focus on a European-based trial with preliminary results and an ongoing American counterpart. The current knowledge of molecular mechanisms behind preterm labor is presented with a focus on the multiple etiologies of preterm labor, both known and presumed, with updates in the basic science realm. Furthermore, we present up-to-date studies on prediction of preterm birth and prematurity-related morbidity.

Fetal echocardiography: z-score reference ranges for a large patient population.

OBJECTIVES: The main goal was to develop new z-score reference ranges for common fetal echocardiographic measurements from a large referral population. METHODS: A retrospective cross-sectional study of 2735 fetuses was performed for standard biometry (biparietal diameter (BPD) and femoral diaphysis length (FDL)) and an assessment of menstrual age (MA). Standardized fetal echocardiographic measurements included aortic valve annulus and pulmonary valve annulus diameters at end-systole, right and left ventricular diameters at end-diastole, and cardiac circumference from a four-chamber view of the heart during end-diastole. Normal z-score ranges were developed for these echocardiographic measurements using MA, BPD and FDL as independent variables. This was accomplished by using first standard regression analysis and then weighted regression of absolute residual values for each parameter in order to adjust for inconstant variance. RESULTS: A simple, linear regression model was the best description of the data in each case and correlations between fetal cardiac measurements and the independent variables were excellent. There was significant heteroscedasticity of standard deviation with increasing gestational age, which also could be modeled with simple linear regression. After this adjustment, the residuals conformed to a normal distribution, validating the calculation and interpretation of z-scores. CONCLUSION: Development of reliable z-scores is possible for common fetal echocardiographic parameters by applying statistical methods that are based on a large sample size and weighted regression of absolute residuals in order to minimize the effect of heteroscedasticity. These normative ranges should be especially useful for the detection and monitoring of suspected fetal cardiac size and growth abnormalities.