Table 1.
Classification System for Maternal‐Fetal‐Neonatal SARS‐CoV‐2 Infections
| Patient | Category | Case Definition |
|---|---|---|
| Maternal infection during pregnancy | ||
| Symptomatic mother | Confirmed | Detection of the virus by PCR in a respiratory sample (nasopharyngeal/ nasal/broncho‐alveolar lavage) |
| Possible | No testing done | |
| Unlikely a | No detection of the virus by PCR in a respiratory sample and no other cause identified | |
| Not infected a | No detection of the virus by PCR in a respiratory sample and other cause identified | |
| Asymptomatic mother who has positive contact history | Confirmed | Detection of the virus by PCR in a respiratory sample |
| Unlikely a | No detection of the virus by PCR in a single respiratory sample | |
| Not infected | No detection of the virus by PCR in two respiratory samples taken at different time points | |
| Congenital infection with intrauterine fetal death/stillbirth | ||
| Fetal tissues or autopsy material | Confirmed | Detection of the virus by PCR from fetal or placental tissue or electron microscopic detection of viral particle in tissue or viral growth in culture from fetal or placental tissue |
| Possible | Detection of the virus by PCR in surface swab from fetus or placental swab on fetal side | |
| Unlikely | Detection of the virus by PCR in surface swab from maternal side of placenta only and no testing done or no detection of the virus by PCR from fetal or placental tissue | |
| Not infected | No detection of the virus by PCR or by electron microscopy in fetal tissue(s) on autopsy | |
| Congenital infection in live born neonate | ||
| Clinical features of infection in newborn and mother with SARS‐CoV‐2 infection | Confirmed | Detection of the virus by PCR in umbilical cord blood b or neonatal blood collected within first 12 hours of birth or amniotic fluid collected prior to rupture of membrane c |
| Probable | Detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) AND placental swab from fetal side of placenta in a neonate born via cesarean section before rupture of membrane or placental tissue | |
| Possible a | No detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) BUT presence of anti‐SARS‐CoV‐2 IgM antibodies in umbilical cord blood or neonatal blood collected within first 12 hours of birth or placental tissue | |
| Unlikely | No detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) or umbilical cord blood, or neonatal blood collected within first 12 hours of birth or amniotic fluid AND antibody testing not done | |
| Not infected | No detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) or umbilical cord blood, or neonatal blood collected within first 12 hours of birth or amniotic fluid AND no anti‐SARS‐CoV‐2 IgM in umbilical cord blood or neonatal blood collected within first 12 hours of birth | |
| No clinical features of infection in newborn and mother with SARS‐CoV‐2 infection | Confirmed | Detection of the virus by PCR in cord blood b or neonatal blood collected within first 12 hours of birth |
| Probable | Detection of the virus by PCR in amniotic fluid collected prior to rupture of membrane but no detection in umbilical cord blood or neonatal blood collected within first 12 hours of birth | |
| Possible | Presence of anti‐SARS‐CoV‐2 IgM in umbilical cord blood or detection of the virus by PCR in placental tissue but no detection of the virus by PCR in umbilical cord blood or neonatal blood collected within first 12 hours of birth or amniotic fluid | |
| Unlikely | No detection of the virus by PCR in cord blood or neonatal blood collected within first 12 hours of birth or amniotic fluid collected prior to rupture of membrane c AND serology not done | |
| Not infected | No detection of the virus by PCR in cord blood or neonatal blood collected within first 12 hours of birth or amniotic fluid collected prior to rupture of membrane c AND no anti‐SARS‐CoV‐2 IgM in cord blood | |
| Neonatal infection acquired intrapartum | ||
| Clinical features of infection in newborn and mother with SARS‐CoV‐2 infection | Confirmed | Detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning the baby) AND at 24‐48 hours of age AND alternate explanation for clinical features excluded |
| Probable | Detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) but not at 24‐48 hours of age AND alternate explanation for clinical features excluded | |
| Possible | No detection of the virus by PCR in nasopharyngeal swab at birth AND detection of the virus by PCR in any of maternal vaginal/placental/cord/skin swab at birth AND alternate explanation for clinical features excluded | |
| Unlikely | No detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) OR in any of maternal vaginal/placental/cord/neonatal nasopharyngeal/skin swab at birth AND alternate explanation for clinical features not identified | |
| Not infected | No detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning baby) OR in any of maternal vaginal/placental/cord/neonatal nasopharyngeal/skin swab at birth AND alternate explanation for clinical features identified | |
| No clinical features of infection in newborn and mother with SARS‐CoV‐2 infection | Confirmed | Detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning the baby) AND at 24‐48 hours of age |
| Possible | Detection of the virus by PCR in nasopharyngeal swab at birth (collected after cleaning the baby) AND not at 24‐48 hours | |
| Not infected | No detection of the virus by PCR in nasopharyngeal swab at birth AND no detection of the virus by PCR in any of vaginal swab in mother/placental swab/skin/cord swab at birth | |
| Neonatal infection acquired postpartum | ||
| Clinical features of infection in newborn at ≥48 hours age (parent or caregiver may or may not have SARS‐CoV‐2 infection or were not tested) | Confirmed | Detection of the virus by PCR in nasopharyngeal/rectal swab at ≥48 hours of birth in a neonate whose respiratory sample tested negative by PCR at birth |
| Probable | Detection of the virus by PCR in nasopharyngeal/rectal swab at ≥48 hours of birth in a neonate who was not tested at birth | |
| Not infected a | No detection of the virus by PCR in nasopharyngeal/rectal swab at ≥48 hours of birth and other cause identified | |
This system is for maternal SARS‐CoV‐2 infection diagnosed prenatally or within 2‐3 weeks of birth.
Category definitions: Confirmed, Strong evidence of infection with confirmatory microbiology; Probable, Strong evidence of infection but confirmatory microbiology lacking; Possible, Evidence suggestive of infection but incomplete; Unlikely, Little support for diagnosis but infection cannot be ruled out; Not infected, No evidence of infection.
Abbreviations: IgM, immunoglobulin M; PCR, polymerase chain reaction.
a
In highly suspicious cases, repeat sample may be needed due to test limitations.
b
Collected using sterile precaution and thorough cleaning of cord.
c
Includes sample taken at cesarean section performed before rupture of membranes.
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