SARS-CoV-2 infection as cause of in-utero fetal death: regional multicenter cohort study

OBJECTIVE

Placental infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to placental insufficiency and in-utero fetal death (IUFD). The objective of this study was to confirm and quantify the extent to which fetoplacental infection with SARS-CoV-2 is a cause of fetal death.

METHODS

This was a multicenter retrospective cohort study of fetal deaths that underwent postmortem examination between January 2020 and January 2022 in three fetal pathology units in Paris, France. All cases of IUFD and termination of pregnancy (TOP) occurring in 31 maternity hospitals in the Paris region undergo detailed placental pathological examination in these units. Databases were searched for cases of IUFD and TOP. Cases with fetal malformation or cytogenetic abnormality were excluded to avoid bias. We included cases of IUFD with a placental or undetermined cause and cases of TOP in the context of severe intrauterine growth restriction (IUGR). Placentas were sent to a single virology unit for reverse-transcription polymerase chain reaction (RT-PCR) testing by a single laboratory technician blinded to the initial postmortem examination report. Our primary endpoint was the proportion of positive placental SARS-CoV-2 RT-PCR tests in the cohort.

RESULTS

Among 147 722 deliveries occurring over 2 years, 788 postmortem examinations for IUFD and TOP for severe IUGR were recorded, of which 462 (58.6%) were included. A total of 13/462 (2.8%) placentas tested positive for SARS-CoV-2 by RT-PCR. Wild-type virus and alpha and delta variants were identified. All positive cases had histological lesions consistent with placental dysfunction. There was a strong correlation between SARS-CoV-2 placentitis and the presence of chronic intervillositis and/or massive fibrin deposits in the placenta. When both lesion types were present, the specificity and negative predictive value for the diagnosis of placental SARS-CoV-2 infection were 0.99 (95% CI, 0.98-1.00) and 0.96 (95% CI, 0.94-0.98), respectively.

CONCLUSIONS

At the height of the SARS-CoV-2 pandemic, the cause of more than half of fetal deaths in the Paris area was determined by postmortem analysis to be of placental or undetermined origin. Of these cases, 2.8% were due to placental SARS-CoV-2 infection with a specific pattern of histological involvement. This study highlights the need for SARS-CoV-2 screening in stillbirth assessment. The impact of vaccination coverage remains to be established. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Secondary prevention of congenital cytomegalovirus infection with valacyclovir following maternal primary infection in early pregnancy

OBJECTIVE

Cytomegalovirus (CMV) maternal primary infection (MPI) in early pregnancy is the main risk factor for congenital CMV (cCMV) infection with long-term sequelae. Our aim was to evaluate, in a single center offering CMV serology screening at 11-14 gestational weeks, secondary prevention of cCMV by administration of high-dosage maternal oral valacyclovir (VACV) in the first trimester of pregnancy.

METHODS

This was a case-control study in a longitudinal cohort of pregnancies with CMV-MPI diagnosed prior to 14 weeks of gestation by serology screening (immunoglobulin (Ig) M and IgG measurement and IgG avidity) between 2009 and 2020. From October 2019 onwards, all women presenting at our center with MPI before 14 weeks' gestation were offered treatment with high-dosage oral VACV (8 g/day, 4 g twice/day). We used propensity score matching to compare fetal infection rates in cases treated with maternal oral VACV (8 g/day) with those in untreated controls. Fetal infection was assessed following amniocentesis at 17-22 weeks of gestation, by polymerase chain reaction (PCR) analysis of amniotic fluid for viral DNA.

RESULTS

Of 310 cases of CMV-MPI identified, 269 underwent amniocentesis for PCR. Of these, 66 were offered, and 65 accepted, treatment with VACV. From the remaining untreated cases, we selected 65 controls, matched for proportion of periconceptional infections and gestational age at amniocentesis. VACV was initiated at a median gestational age of 12.71 (interquartile range (IQR), 10.00-13.86) weeks and the median duration of treatment was 35 (IQR, 26-54) days. On multivariate logistic regression, fetal infection was lower in the treated group (odds ratio, 0.318 (95% CI, 0.120-0.841); P = 0.021). One treated patient developed acute renal failure 4 weeks after initiation of VACV therapy, but this resolved within 5 days after treatment was stopped.

CONCLUSION

This study confirms the acceptability, tolerance and benefit of secondary prevention by VACV of cCMV infection in a clinical setting with a well-established routine maternal serum screening policy in the first trimester of pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

First-trimester diagnosis of congenital cytomegalovirus infection after maternal primary infection in early pregnancy: feasibility study of viral genome amplification by PCR on chorionic villi obtained by CVS

OBJECTIVE

To evaluate the feasibility of amplification of the viral genome by polymerase chain reaction (PCR) analysis of trophoblast samples obtained by chorionic villus sampling (CVS) in cases of maternal primary infection (MPI) with cytomegalovirus (CMV) in early pregnancy.

METHODS

This was a prospective study carried out at the Department of Obstetrics and Fetal Medicine, Hopital Necker-E.M., between October 2019 and October 2020. Following CMV serology screening in early pregnancy, CVS was offered to women at 11-14 weeks' gestation after CMV-MPI ≤ 10 weeks. Array-comparative genomic hybridization and amplification of the viral genome by PCR were performed on the trophoblasts obtained by CVS. All cases also underwent amniocentesis from 17 weeks onwards and PCR was performed on the amniotic fluid. Secondary prevention with valacyclovir was initiated as soon as MPI was diagnosed, to decrease the risk of vertical transmission. We evaluated the diagnostic performance of CMV-PCR of trophoblast obtained by CVS, using as the reference standard PCR of amniotic fluid obtained by amniocentesis.

RESULTS

CVS was performed in 37 pregnancies, at a median (range) gestational age of 12.7 (11.3-14.4) weeks. CMV-PCR in chorionic villi was positive in three and negative in 34 cases. CMV-PCR following amniocentesis, performed at a median (range) gestational age of 17.6 (16.7-29.9) weeks, was positive for the three cases which were positive following CVS and, of the 34 patients with a negative finding following CVS, amniocentesis was negative in 31 and positive in three. The sensitivity of CMV-PCR analysis of trophoblast obtained by CVS for the diagnosis of CMV, using as the reference standard PCR analysis of amniotic fluid obtained by amniocentesis, was 50% (95% CI, 19-81%), specificity was 100% (95% CI, 89-100%), positive predictive value was 100% (95% CI, 44-100%) and negative predictive value was 91% (95% CI, 77-97%).

CONCLUSIONS

Diagnosis of placental infection following MPI in early pregnancy can be achieved by PCR amplification of the CMV genome in chorionic villi. We propose that negative CMV-PCR in the trophoblast after 12 weeks could be used to exclude CMV-related embryopathy leading to sequelae. However, this needs to be confirmed through long-term follow-up evaluation. These findings could help to establish CVS as the diagnostic test of choice following maternal serology screening in early pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Maternal infections: revisiting the need for screening in pregnancy

The decision to implement screening for infections during pregnancy depends upon epidemiological, economic, therapeutic and test performance criteria. It therefore varies with public health priorities from country to country. When screening is implemented, the first trimester has become the best time slot to build individual care pathways in this field. This is most relevant for evaluating the risk of embryonic consequences, planning diagnostic testing, initiating primary or secondary prevention and optimising the accuracy of ultrasound follow-up. This article is a critical appraisal of epidemiological data and current international screening recommendations for infections in pregnancy. TWEETABLE ABSTRACT: Screening for infections in pregnancy: a critical review of current epidemiological evidence and international guidelines.

Refining the prognosis of fetuses infected with Cytomegalovirus in the first trimester of pregnancy by serial prenatal assessment: a single-centre retrospective study

OBJECTIVE

To define the predictive value (PV) of known prognostic factors of fetal infection with Cytomegalovirus following maternal primary infection <14 weeks of gestation, at different time points of pregnancy: the end of the second trimester; following prenatal magnetic resonance imaging (MRI) at 32 weeks of gestation; and using all ultrasound scans performed in the third trimester (US3rdT).

DESIGN

A retrospective study.

SETTING

Reference fetal medicine unit.

POPULATION

Sixty-two fetuses infected <14 weeks of gestation.

METHODS

We defined second-trimester assessment (STA) as the combination of ultrasound findings <28 weeks of gestation and fetal platelet count at cordocentesis. Three groups were defined: normal, extracerebral, and cerebral STA.

MAIN OUTCOME MEASURES

For each group, the PV of STA alone, STA + MRI, and STA + US3rdT were assessed retrospectively. Outcome at birth and at follow-up were reported.

RESULTS

The STA was normal, and with extracerebral and cerebral features, in 43.5, 42.0, and 14.5%, respectively. The negative PV of normal STA and MRI for moderate to severe sequelae was 100%. The residual risk was unilateral hearing loss in 16.7% of cases. Of pregnancies with cerebral STA, 44% were terminated. Following extracerebral STA, 48% of neonates were symptomatic and 30% had moderate to severe sequelae. In those cases, the positive and negative PV of MRI for sequelae were 33 and 73%, respectively. STA + US3rdT had a lower negative PV than MRI for symptoms at birth and for moderate to severe sequelae. Any false-positive findings at MRI were mostly the result of hypersignals of white matter.

CONCLUSIONS

Serial assessment in the second and third trimesters by ultrasound and MRI is necessary to predict the risk of sequelae occurring in 35% of pregnancies following fetal infection in the first trimester of pregnancy.

TWEETABLE ABSTRACT

Serial ultrasound prognostic assessment following fetal CMV infection in the 1st trimester is improved by MRI at 32 weeks.