Preeclampsia in pregnant women with COVID-19: a prospective cohort study from two tertiary hospitals in Southern Brazil.

Background: COVID-19 is an infectious pathology that shows vascular changes during pregnancy, as well as in the placentas. The main objectives of this study were to estimate the prevalence and the risk factors for preeclampsia in hospitalized pregnant women with COVID-19. As well as comparing maternal and perinatal outcomes in hospitalized pregnant women with COVID-19 and preeclampsia with those without preeclampsia. Methods: Prospective cohort study of 100 hospitalized pregnant women from two tertiary hospitals, diagnosed with COVID-19, and divided into two groups: PE+ group (pregnant women with COVID-19 and preeclampsia) and PE- group (pregnant women with COVID-19 without preeclampsia). These pregnant women had prevalence, risk factors, maternal and perinatal data analyzed. Results: The prevalence of preeclampsia was 11%. Severe COVID-19 was the main risk factor for preeclampsia (OR = 8.18 [CI 1.53-43.52]), as well as fetal growth restriction was the main perinatal outcome (OR = 8.90 [CI 1.52-38.4]). Comorbidities were more frequent in the PE+ group (63.6% vs 31.5%, p = 0.03), as well as prematurity (81.8% vs 41.6%, p = 0.02), low birth weight (63.6% vs 24.7%, p = 0.01), and the need for neonatal intensive care admission of the newborn (63.6% vs 27.0%, p = 0.03). Pregnant women with PE had twice as long a length of stay in the intensive care unit (RR = 2.35 [CI 1.34-4.14]). Although maternal mortality was more frequent among pregnant women with PE, it was not statistically significant. Conclusions: Prevalence of preeclampsia in hospitalized pregnant women with COVID-19 was 11%. Severe COVID-19 was the main risk factor for preeclampsia and associated comorbidities increased the risk for developing preeclampsia. Long length of stay in the intensive care unit was the main maternal outcome and fetal growth restriction was the main perinatal outcome of preeclampsia.

HIV, Placental Lesions, and Adverse Perinatal Outcomes.

Africa has the highest number of pregnant women with human immunodeficiency virus (HIV). In some studies, HIV has been associated with adverse perinatal outcomes. However, the pathophysiological mechanism leading to adverse fetal outcomes is not known. Maternal vascular malformation, chorioamnionitis, and decreased placental weight have been described as placental features associated with HIV in some studies. The use of antiretroviral therapy has reduced perinatal transmission of HIV and adverse fetal outcomes. However, placental mechanisms associated with HIV and the fetal immune response to maternal HIV infection are poorly understood. Additional research is required to understand whether altered maternal immunity in women living with HIV can trigger fetal responses leading to stillbirth or preterm birth.

The Effects of COVID-19 on the Placenta During Pregnancy.

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. The virus primarily affects the lungs where it induces respiratory distress syndrome ranging from mild to acute, however, there is a growing body of evidence supporting its negative effects on other system organs that also carry the ACE2 receptor, such as the placenta. The majority of newborns delivered from SARS-CoV-2 positive mothers test negative following delivery, suggesting that there are protective mechanisms within the placenta. There appears to be a higher incidence of pregnancy-related complications in SARS-CoV-2 positive mothers, such as miscarriage, restricted fetal growth, or still-birth. In this review, we discuss the pathobiology of COVID-19 maternal infection and the potential adverse effects associated with viral infection, and the possibility of transplacental transmission.

Late-onset intrauterine growth restriction and HHV-6 infection: A pilot study.

Late-onset Intrauterine growth restriction (IUGR) refers to impaired growth and development of the fetus, characterized by placental morphological abnormalities that affect the fetus's supply of nutrients. Human leukocyte antigen-G (HLA-G) is physiologically expressed during pregnancy, but decreased in normal placenta during the last weeks of gestation possibly inducing childbirth. Several viruses involved in congenital infection, such as herpesviruses, exploit HLA-G expression as an immune-escape mechanism. To date, despite different congenital herpetic infections having been associated with late IUGR, no direct implication of Human herpesvirus 6 (HHV-6) infection has been reported. We evaluated HLA-G expression and HHV-6 infection in 11 placentas from late-onset IUGR newborns and 11 placentas from uncomplicated pregnancies by histopathological and immunohistochemistry analysis. We found higher levels of HLA-G expression and HHV-6 presence in IUGR placenta samples compared with control placenta samples. We report HHV-6 staining in IUGR placenta samples, characterized by high HLA-G expression. These preliminary data suggest a possible involvement of HHV-6 infection in HLA-G deregulation that might affect vessel remodeling and prevent the correct pregnancy outcome in the IUGR condition.

Vertical Transmission of SARS-CoV-2 in Second Trimester Associated with Severe Neonatal Pathology.

The effects of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in women on the gestation course and the health of the fetus, particularly in the first and second trimesters, remain very poorly explored. This report describes a case in which the normal development of pregnancy was complicated immediately after the patient had experienced Coronavirus disease 2019 (COVID-19) at the 21st week of gestation. Specific conditions included critical blood flow in the fetal umbilical artery, fetal growth restriction (1st percentile), right ventricular hypertrophy, hydropericardium, echo-characteristics of hypoxic-ischemic brain injury (leukomalacia in periventricular area) and intraventricular hemorrhage at the 25th week of gestation. Premature male neonate delivered at the 26th week of gestation died after 1 day 18 h due to asystole. The results of independent polymerase chain reaction (PCR), mass spectrometry and immunohistochemistry analyses of placenta tissue, umbilical cord blood and child blood jointly indicated vertical transmission of SARS-CoV-2 from mother to the fetus, which we conclude to be the major cause for the development of maternal vascular malperfusion in the studied case.

Human Herpesviruses 6A and 6B in Reproductive Diseases.

Human herpesviruses 6A (HHV-6A) and human herpesvirus 6B (HHV-6B)-collectively, HHV-6A/B-are recently-discovered but ancient human viruses. The vast majority of people acquire one or both viruses, typically very early in life, producing an ineradicable lifelong infection. The viruses have been linked to several neurological, pulmonary and hematological diseases. In early human history, the viruses on multiple occasions infected a germ cell, and integrated their DNA into a human chromosome. As a result, about 1% of humans are born with the full viral genome present in every cell, with uncertain consequences for health. HHV-6A may play a role in 43% of cases of primary unexplained infertility. Both the inherited and acquired viruses may occasionally trigger several of the factors that are important in the pathogenesis of preeclampsia. Transplacental infection occurs in 1-2% of pregnancies, with some evidence suggesting adverse health consequences for the child. While emerging knowledge about these viruses in reproductive diseases is not sufficient to suggest any changes in current practice, we write this review to indicate the need for further research that could prove practice-changing.

Performance of a local reference curve for predicting small for gestational age fetuses in pregnant women with HIV/AIDS.

PURPOSE: To compare the performance of a local estimated fetal weight curve with curves established for other populations to predict small for gestational age (SGA) fetuses. METHODS: A retrospective and cross-sectional study involving 231 fetuses in which the performance of a local curve (proposed model) was compared with the Hadlock and Intergrowth-21st curves in the prediction of SGA fetuses, by applying them to a population of high-risk pregnant woman with HIV/AIDS. For each model, a receiver operating characteristic curve was adjusted, considering the SGA classification by the neonatal Intergrowth method as the gold standard, and the area under the curve (AUC) was calculated. RESULTS: The models presented linear correlations with each other. The agreement of the proposed model with Hadlock was very good (kappa = 0.83), whereas the proposed model and Intergrowth-21st had moderate agreement (kappa = 0.44). The SGA fetus detection sensitivities of the proposed model and Hadlock were 61.9% and 57.1%, with specificity of 84.1% and 86.2% and accuracy of 80.1% and 81%, respectively, without statistical difference. The sensitivity of the Intergrowth-21st model was 33.3%, while the accuracy was 85.7% and the specificity was 97.4%. The AUC estimated values for the Hadlock, proposed, and Intergrowth-21st models were 0.834, 0.832, and 0.835, respectively. CONCLUSION: The proposed model and Hadlock were interchangeable in the prediction of SGA fetuses and superior to the Intergrowth-21st model.

Pregnancy and neonatal outcomes of COVID-19: coreporting of common outcomes from PAN-COVID and AAP-SONPM registries.

OBJECTIVE: Few large cohort studies have reported data on maternal, fetal, perinatal and neonatal outcomes associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy. We report the outcome of infected pregnancies from a collaboration formed early during the pandemic between the investigators of two registries, the UK and Global Pregnancy and Neonatal outcomes in COVID-19 (PAN-COVID) study and the American Academy of Pediatrics (AAP) Section on Neonatal-Perinatal Medicine (SONPM) National Perinatal COVID-19 Registry. METHODS: This was an analysis of data from the PAN-COVID registry (1 January to 25 July 2020), which includes pregnancies with suspected or confirmed maternal SARS-CoV-2 infection at any stage in pregnancy, and the AAP-SONPM National Perinatal COVID-19 registry (4 April to 8 August 2020), which includes pregnancies with positive maternal testing for SARS-CoV-2 from 14 days before delivery to 3 days after delivery. The registries collected data on maternal, fetal, perinatal and neonatal outcomes. The PAN-COVID results are presented overall for pregnancies with suspected or confirmed SARS-CoV-2 infection and separately in those with confirmed infection. RESULTS: We report on 4005 pregnant women with suspected or confirmed SARS-CoV-2 infection (1606 from PAN-COVID and 2399 from AAP-SONPM). For obstetric outcomes, in PAN-COVID overall and in those with confirmed infection in PAN-COVID and AAP-SONPM, respectively, maternal death occurred in 0.5%, 0.5% and 0.2% of cases, early neonatal death in 0.2%, 0.3% and 0.3% of cases and stillbirth in 0.5%, 0.6% and 0.4% of cases. Delivery was preterm (< 37 weeks' gestation) in 12.0% of all women in PAN-COVID, in 16.1% of those women with confirmed infection in PAN-COVID and in 15.7% of women in AAP-SONPM. Extreme preterm delivery (< 27 weeks' gestation) occurred in 0.5% of cases in PAN-COVID and 0.3% in AAP-SONPM. Neonatal SARS-CoV-2 infection was reported in 0.9% of all deliveries in PAN-COVID overall, in 2.0% in those with confirmed infection in PAN-COVID and in 1.8% in AAP-SONPM; the proportions of neonates tested were 9.5%, 20.7% and 87.2%, respectively. The rates of a small-for-gestational-age (SGA) neonate were 8.2% in PAN-COVID overall, 9.7% in those with confirmed infection and 9.6% in AAP-SONPM. Mean gestational-age-adjusted birth-weight Z-scores were -0.03 in PAN-COVID and -0.18 in AAP-SONPM. CONCLUSIONS: The findings from the UK and USA registries of pregnancies with SARS-CoV-2 infection were remarkably concordant. Preterm delivery affected a higher proportion of women than expected based on historical and contemporaneous national data. The proportions of pregnancies affected by stillbirth, a SGA infant or early neonatal death were comparable to those in historical and contemporaneous UK and USA data. Although maternal death was uncommon, the rate was higher than expected based on UK and USA population data, which is likely explained by underascertainment of women affected by milder or asymptomatic infection in pregnancy in the PAN-COVID study, although not in the AAP-SONPM study. The data presented support strong guidance for enhanced precautions to prevent SARS-CoV-2 infection in pregnancy, particularly in the context of increased risks of preterm delivery and maternal mortality, and for priority vaccination of pregnant women and women planning pregnancy. Copyright © 2021 ISUOG. Published by John Wiley & Sons Ltd.

Are routine genetic and urine cytomegalovirus testing useful investigations in symmetrically growth restricted infants?

In this six-year study, there were 1118 newborn genetic testing; there were 162 genetic testing for symmetrically growth retarded infants. Out of this, only six infants had positive results yielding a low odds ratio of 0.21 for having any significant chromosome results. Urine CMV testing was positive only in one infant out of 118 tested.

Association Between Maternal Human Papillomavirus Infection and Adverse Pregnancy Outcomes: Systematic Review and Meta-Analysis.

BACKGROUND: Experimental studies provide evidence of the harmful effect of human papillomavirus (HPV) infection on pregnancy, but observational studies are inconclusive. We systematically assessed the association between HPV and adverse pregnancy outcomes. METHODS: We searched electronic databases up to December 1, 2019. We included observational studies on the association between HPV and adverse pregnancy outcomes. We conducted a random-effect meta-analysis for each outcome and assessed heterogeneity between studies. RESULTS: From 3034 citations, we included 38 studies and quantitatively synthesized 36 studies. Human papillomavirus was significantly associated with preterm birth (age-adjusted odds ratio [aOR], 1.50; 95% confidence interval [CI], 1.19-1.88), preterm premature rupture of membranes (aOR, 1.96; 95% CI, 1.11-3.45), premature rupture of membranes (aOR, 1.42; 95% CI, 1.08-1.86), intrauterine growth restriction (aOR, 1.17; 95% CI, 1.01-1.37), low birth weight (aOR, 1.91; 95% CI, 1.33-2.76), and fetal death (aOR, 2.23; 95% CI, 1.14-4.37). No significant association was found for spontaneous abortion (aOR, 1.14; 95% CI, 0.40-3.22) and pregnancy-induced hypertensive disorders (aOR, 1.24; 95% CI, 0.80-1.92). Most of the studies were of moderate or low quality, and substantial between-studies heterogeneity remained unexplained. CONCLUSIONS: We found a consistent and significant association between HPV and preterm birth and preterm premature rupture of membranes. Human papillomavirus may also be associated with intrauterine growth restriction, low birth weight, and fetal death, but findings are limited by suboptimal control of biases.

Maternal and neonatal infections of herpes simplex virus-1 and cytomegalovirus in Saudi Arabia.

It is common practice to screen for human cytomegalovirus (CMV) and herpes simplex virus (HSV) among women with infertility problems, recurrent abortion or exhibiting intrauterine growth restriction during pregnancy. Nonetheless, limited information exists about the incidence of these viruses in Saudi Arabia. The IgG and IgM antibodies of 761 women and 85 of neonates who showed intrauterine growth retardation (IUGR) were reviewed against cytomegalovirus and herpes simplex virus-1. Tests were repeated only for those with positive results. Recent infection of herpes simplex virus-1 and cytomegalovirus was evidenced by the presence of IgM in the female patients: incidence was 1.1% and 1.3% respectively. None of the neonates showed positive IgM for cytomegalovirus, but a single case showed a positive result for herpes simplex virus-1 IgM. Among the female patients, however, the presence of IgG indicated previous exposure to cytomegalovirus in 92% of cases and herpes simplex virus in 80.8%. It was concluded that although previous exposure to CMV and HSV-1 were found in high percentages in women experiencing infertility problems but did not appear to be associated with neonates exhibiting intrauterine growth retardation.

Urinary bladder agenesis and renal hypoplasia potentially related to in utero Zika virus infection.

This case report describes the clinical findings of a 22-year-old pregnant woman with confirmed Zika virus infection, at 16 weeks of gestation, in Sucre, Colombia. Her ultrasound revealed severe oligohydramnios, intrauterine growth restriction, and a complete absence of the urinary bladder of the fetus. The poor prognosis led to the decision to terminate the pregnancy. Autopsy of the fetus revealed severe bilateral renal hypoplasia.

Human papillomavirus infection and intrauterine growth restriction: a data-linkage study.

OBJECTIVE: Using unbiased population data, to examine whether having a positive Pap smear, and thus a high probability of Human Papilloma Virus (HPV) infection, is a significant risk factor for intrauterine growth restriction (IUGR) in a subsequent pregnancy. STUDY DESIGN AND METHODS: Two independent population-based databases, namely the South Australian Perinatal Statistics Collection and the South Australian Cervical Screening Database, were deidentified and linked by the SANT Datalinkage Service. Analyses were performed on cases where Pap smear screening data was available for up to 2 years prior to a singleton live birth. Population characteristics and pregnancy related data were compared statistically by normal birth weight versus IUGR (10th percentile - known as small for gestational age (SGA), small for gestational age) and (3rd percentile birth weight - known as VLBW, very low birth weight). The association between cervical screening results and IUGR was assessed using generalized linear log binomial regression models. RESULTS: A total of 31,827 women met the criteria. Of these, 1311 women (4.1%) had a positive Pap smear within 2 years of the current pregnancy. Those having a positive Pap smear were more likely to have a baby with IUGR than those with negative smear results. For SGA, 5.8% babies were from mothers with positive Pap smears compared to 4.0% with negative smears indicating a 40% higher risk of having an SGA baby (95%CI 20-70%) among women with positive Pap smears. For VLBW, 7.6% mothers had positive Pap smears compared with 4.0% with negative smears (p < .001), which reflects a 90% increased risk (95%CI 40-150%). These associations reduced to 20% (95%CI 1-40%) and 50% (95%CI 10-100%) for SGA and VLBW, respectively, after adjusting for all other significant covariates including maternal age, ethnicity, marital status, occupation, smoking, pregnancy history, and maternal health during pregnancy. CONCLUSIONS: Mothers with a positive Pap smear have an increased risk of IUGR, especially for VLBW, which is independent of other risk factors. The results confirm previous findings in a small study and emphasise the need to consider the risks of both cancer and IUGR in all HPV vaccination programs.

Prospective Cohort Study of Congenital Cytomegalovirus Infection during Pregnancy with Fetal Growth Restriction: Serologic Analysis and Placental Pathology.

OBJECTIVE: To investigate prospectively the prevalence of congenital cytomegalovirus (CMV) infection and the pathologic features of the placenta in cases of fetal growth restriction (FGR). STUDY DESIGN: Forty-eight pregnant women who were diagnosed with FGR during pregnancy were enrolled for 15 months. Maternal CMV serologic tests, pathologic examinations of the placenta, and newborn urinary CMV-DNA polymerase chain reaction tests were performed in all the cases. The clinical characteristics and laboratory findings of the pregnant women and their newborns were collected. Biomarkers for inflammation, angiogenesis, and placental hormones were measured in the maternal serum at FGR diagnosis or in the neonatal urine at birth. RESULTS: One of the 48 cases with FGR was a congenital CMV infection. CMV antigen was detected in the placenta of 7 cases with FGR. The change rate of the estimated fetal body weight was significantly lower in FGR cases with placental CMV detection. Placental villitis was observed more frequently in FGR cases with placental CMV detection. Human placental lactogen was significantly decreased in FGR cases with placental CMV detection. Increased C-reactive protein and serum amyloid A levels in the maternal serum were observed more frequently in FGR cases with placental CMV detection. Newborn urine ß-2 microglobulin levels were significantly higher in FGR cases with placental CMV detection. CONCLUSIONS: Serologic tests for maternal CMV, the change rate of the estimated fetal body weight, analysis of several biomarkers, and placental pathologic examinations might be helpful in comprehensively predicting the possibility of congenital CMV infection.

Effects of Zika infection on growth.

OBJECTIVES: To present the currently available evidence of the effects of congenital Zika virus infection on infant growth, to discuss possible intervening factors, and to describe preliminary data on this growth in a cohort of exposed children. SOURCE OF DATA: Non-systematic review in PubMed, BVS, CAPES, Scopus, Web of Science, Cochrane and Google Scholar databases in the last 5 years, using the terms infection/disease by Zika virus and growth/nutrition/nutritional status/infant nutrition and nutritional needs. Additionally, the anthropometric data of the first 2.5 years of a cohort of children exposed to the Zika virus during pregnancy were reviewed. SYNTHESIS OF DATA: Both intrauterine growth restriction and low birth weight were reported in series of cases of children with congenital Zika syndrome. The postnatal growth deficit of these children appears to be directly proportional to the degree of neurological impairment. The etiology is multifactorial, and nutritional and non-nutritional factors are probably involved. The data from the present cohort show that the head circumference evolution depends on this measurement at birth and that weight-height growth has a trend toward lower weight and length in children with congenital microcephaly and normocephalic at birth who develop some neurological abnormality. CONCLUSIONS: The few existing data suggest that, in children with congenital Zika, the greater the degree of neurological impairment, the greater the impact on growth, whether or not associated with microcephaly at birth.

Effects of Zika infection on growth / Repercussões da infecção por Zika sobre o crescimento

Abstract Objectives: To present the currently available evidence of the effects of congenital Zika virus infection on infant growth, to discuss possible intervening factors, and to describe preliminary data on this growth in a cohort of exposed children. Source of data: Non-systematic review in PubMed, BVS, CAPES, Scopus, Web of Science, Cochrane and Google Scholar databases in the last 5 years, using the terms infection/disease by Zika virus and growth/nutrition/nutritional status/infant nutrition and nutritional needs. Additionally, the anthropometric data of the first 2.5 years of a cohort of children exposed to the Zika virus during pregnancy were reviewed. Synthesis of data: Both intrauterine growth restriction and low birth weight were reported in series of cases of children with congenital Zika syndrome. The postnatal growth deficit of these children appears to be directly proportional to the degree of neurological impairment. The etiology is multifactorial, and nutritional and non-nutritional factors are probably involved. The data from the present cohort show that the head circumference evolution depends on this measurement at birth and that weight-height growth has a trend toward lower weight and length in children with congenital microcephaly and normocephalic at birth who develop some neurological abnormality. Conclusions: The few existing data suggest that, in children with congenital Zika, the greater the degree of neurological impairment, the greater the impact on growth, whether or not associated with microcephaly at birth.

Resumo Objetivos: Apresentar as evidências atualmente disponíveis das repercussões da infecção congênita pelo vírus Zika no crescimento infantil, discutir possíveis fatores intervenientes e descrever dados preliminares desse crescimento em uma coorte de crianças expostas. Fonte dos dados: Revisão não sistemática nos portais de banco de dados PubMed, BVS, Capes, Scopus, Web of Science, Cochrane e Google Scholar nos últimos cinco anos, com o uso dos termos infecção/doença pelo vírus Zika e crescimento/nutrição/status nutricional/nutrição infantil e necessidades nutricionais. Além disso, foram revistos os dados antropométricos dos primeiros dois anos e meio de uma coorte de crianças expostas ao vírus Zika durante a gestação. Síntese dos dados: Tanto a restrição do crescimento intrauterino como o baixo peso ao nascer têm sido relatados em séries de casos de crianças com síndrome de Zika congênita. O déficit de crescimento pós-natal dessas crianças parece ser diretamente proporcional ao grau de comprometimento neurológico. A etiologia é multifatorial, com fatores nutricionais e não nutricionais provavelmente envolvidos. Os dados de nossa coorte mostram que a evolução do perímetro cefálico é dependente do valor dessa medida ao nascimento e que o crescimento pondero-estatural apresenta uma tendência de menor peso e comprimento em crianças com microcefalia congênita e normocefálicas ao nascimento, mas com alguma anormalidade neurológica evolutiva. Conclusões: Os poucos dados existentes sugerem que em crianças com Zika congênita, o impacto sobre o crescimento será tanto maior quanto maior for o grau de comprometimento neurológico, associado ou não à microcefalia ao nascimento.

Consequences of in utero exposure to Zika virus in offspring of AG129 mice.

Zika virus (ZIKV) can cause various diseases in offspring after congenital infection. The purpose of this study was to identify disease phenotypes in pups exposed to ZIKV in utero. Female interferon-α/ß, -γ receptor knockout mice (AG129) were infected intraperitoneally with ZIKV 7.5 days' post coitus (dpc). Viral RNA, antigen and infectious virus were detected in some, but not all, maternal and fetal tissues at various times during gestation. Fetuses of infected dams had significant intrauterine growth restriction (IUGR), which was more pronounced as females neared parturition. Pups born to infected dams were significantly smaller and had significantly shortened skull lengths, as determined by measurement with a caliper and by micro-CT analysis, as compared with age-matched controls. Growth rates of exposed pups after birth, however, was similar to sham-exposed offspring. Viral RNA was detected in pups of infected dams after birth. A lower survival rate was observed in neonates exposed to ZIKV in utero. A mortality rate of over 50%, attributed to consequences of ZIKV infection, occurred after birth in pups born to infected dams. A transient hearing loss was observed in some animals exposed to virus in utero. No motor deficits or cognitive deficits were detected using running wheel or viral paresis scoring assays. Abnormalities in offspring included smaller size, shorter skull length and increased neonatal mortality, while the only functional deficit we could detect was a low incidence of transient hearing loss.

Ultrasound Findings Associated With Antepartum Viral Infection.

This article reviews the sonographic manifestations of fetal infection and the role of ultrasound in the evaluation of the fetus at risk for congenital infection. Several ultrasound findings have been associated with in utero fetal infections. For the patient with a known or suspected fetal infection, sonographic identification of characteristic abnormalities can provide useful information for counseling and perinatal management. Demonstration of such findings in the low-risk patient may serve to identify the fetus with a previously unsuspected infection. The clinician should understand the limitations of ultrasound in the prenatal diagnosis of congenital infection and discuss them with the patient.

Type I interferons instigate fetal demise after Zika virus infection.

Zika virus (ZIKV) infection during pregnancy is associated with adverse fetal outcomes, including microcephaly, growth restriction, and fetal demise. Type I interferons (IFNs) are essential for host resistance against ZIKV, and IFN-α/ß receptor (IFNAR)-deficient mice are highly susceptible to ZIKV infection. Severe fetal growth restriction with placental damage and fetal resorption is observed after ZIKV infection of type I IFN receptor knockout (Ifnar1-/-) dams mated with wild-type sires, resulting in fetuses with functional type I IFN signaling. The role of type I IFNs in limiting or mediating ZIKV disease within this congenital infection model remains unknown. In this study, we challenged Ifnar1-/- dams mated with Ifnar1+/- sires with ZIKV. This breeding scheme enabled us to examine pregnant dams that carry a mixture of fetuses that express (Ifnar1+/-) or do not express IFNAR (Ifnar1-/-) within the same uterus. Virus replicated to a higher titer in the placenta of Ifnar1-/- than within the Ifnar1+/- concepti. Yet, rather unexpectedly, we found that only Ifnar1+/- fetuses were resorbed after ZIKV infection during early pregnancy, whereas their Ifnar1-/- littermates continue to develop. Analyses of the fetus and placenta revealed that, after ZIKV infection, IFNAR signaling in the conceptus inhibits development of the placental labyrinth, resulting in abnormal architecture of the maternal-fetal barrier. Exposure of midgestation human chorionic villous explants to type I IFN, but not type III IFNs, altered placental morphology and induced cytoskeletal rearrangements within the villous core. Our results implicate type I IFNs as a possible mediator of pregnancy complications, including spontaneous abortions and growth restriction, in the context of congenital viral infections.