TORCH syndrome consists of infections in a neonate or a fetus due to any of the following: Toxoplasma gondii, rubella virus, cytomegalovirus, and herpes simplex virus. These infections are grouped together as their clinical manifestations are almost identical and they account for a majority of the perinatal morbidity and congenital anomalies. They rarely cause symptoms in a pregnant woman but they influence the pregnancy and are an important cause of a poor fetal outcome.
The acronym TORCH means toxoplasmosis, rubella virus, cytomegalovirus (CMV), and herpes simplex viruses. TORCH syndrome consists of a cluster of similar manifestations caused by these agents which account for most of the perinatal infections associated with serious fetal and neonatal morbidity and mortality  . Effects of the infections include spontaneous abortions, intrauterine fetal death, fetal growth restriction, congenital fetal anomalies, premature deliveries, and stillbirths . Risk factors for TORCH infection include pregnancy and immunocompromised state .
Toxoplasma gondii is a protozoan parasite which causes toxoplasmosis. Women become infected after consuming contaminated food or water. Following ingestion of the cysts, there is an incubation period ranging from one to three weeks. The infected woman usually does not develop any clinical manifestations but if pregnant, may suffer miscarriages, stillbirth, or may deliver a baby with congenital malformations  .
Rubella is a viral disease acquired through droplet infection. A pregnant woman, when infected, may have mild symptoms or may be asymptomatic but can transfer the infection vertically to her fetus via the placenta . This can result in congenital anomalies if the infection occurs during the period of fetal organogenesis leading to fetal cardiac defects, cataracts, and hearing loss which together constitute the congenital rubella syndrome .
CMV infection is transmitted via direct contact with infected body fluids . The incubation period ranges from one to three months and a pregnant woman can transmit the infection to the fetus transplacentally leading to fetal growth retardation, intracranial calcification with microcephaly, hepatosplenomegaly, chorioretinitis, thrombocytopenic purpura, and anemia .
Herpes simplex viral infection can be due to herpes simplex virus 1 (HSV1) or herpes simplex virus 2 (HSV2). HSV1 is transmitted by contacts of non-sexual nature while HSV2 is transmitted sexually. A majority of genital herpes infections in pregnancy are asymptomatic but can cause significant fetal morbidity and mortality with spontaneous abortions, premature delivery, and neonatal herpes infection    .
It is difficult to diagnose TORCH infections in pregnant women clinically as patients are often asymptomatic and do not manifest any signs. Serology testing forms the mainstay with the detection of corresponding antibodies. Polymerase chain reaction (PCR) is also used to identify the infection and for subsequent follow-up . An adequate diagnosis may require a laboratory which offers specialized tests as serology is difficult to interpret, especially in CMV infection.
A primary CMV infection can be diagnosed in a pregnant woman by positive CMV IgM, IgG, and low IgG avidity, while more precise methods are composed of PCR testing of urine or serum samples and a rapid virus isolation. PCR is also used to detect HSV from genital lesions in pregnancy. Cultures from infected skin, oral and ocular lesions or cerebrospinal fluid (CSF) in infected neonates can help to diagnose HSV infection. Rubella can be detected in a pregnant woman with IgM and IgG antibody levels . In ambiguous cases, amniotic fluid PCR and viral culture may be required to confirm the diagnosis.Ultrasonography is indicated to detect fetal complications resulting from these perinatal infections. Findings include fetal growth retardation, cardiac defects, microcephaly and intracranial calcifications in the case of CMV infection.
Ultrasonography is indicated to detect fetal complications resulting from TORCH infections. Findings may include fetal growth retardation, cardiac defects, microcephaly, and intracranial calcifications. A fetal echocardiogram can be performed if cardiac anomalies are detected on ultrasonography. Invasive tests like chorionic villus sampling and amniocentesis can also be performed to confirm TORCH syndrome but these tests are associated with a high incidence of fetal morbidity and loss.
Invasive tests like chorionic villus sampling and amniocentesis can also be performed to confirm TORCH syndrome but these tests are associated with a significant possibility of complications.