Nahmia called the complex combination of perinatal infections TORCH, toxoplasma (To), rubella (R), cytomegalovirus (C), and herpes simplex virus type 1 or 2 (H). It has been almost half a century since the concept of TORCH was introduced. Should screening tests for antibodies to the 4 pathogenic microorganisms be performed during pregnancy? How should it be done? This is still a controversial issue in the medical community.
Cytomegalovirus screening
1. Routine cytomegalovirus screening is performed in pregnant women using serological methods and quantitative urine CMV-DNA testing.
2. Cytomegalovirus serologic testing can be considered for pregnant women with influenza-like symptoms or ultrasound findings that indicate cytomegalovirus infection during pregnancy.
3. Health care providers and caregivers who are seronegative (IgG negative) should undergo serologic surveillance during pregnancy. Serologic surveillance should also be performed for pregnant women (IgG negative) who are at risk of exposure to infant urine and saliva.
4. The diagnosis of initial maternal giant cell infection during pregnancy should be based on the new appearance of virus-specific IgG antibodies in the serum of pregnant women (who have previously been seronegative) or the finding of specific IgM antibodies accompanied by a decrease in IgG antibody affinity.
5. The diagnosis of recurrent infection should be based on a pregnant woman who has previously tested positive for IgG antibodies, a significant increase in the current IgG antibody titer (4-fold increase in quantitative testing), with or without the presence of IgM antibodies, and a high affinity for IgG (≤ 16 weeks); a positive saliva or throat swab specimen or other human tissue culture for cytomegalovirus; or a positive urine, saliva or throat swab specimen or other human tissue culture for cytomegalovirus. High cytomegalovirus copy number by quantitative PCR from urine, saliva or throat swab or other human tissues.
For first-time infected pregnant women, the couple should be informed that the risk of intrauterine vertical transmission and fetal infection is 30-40%, and if the fetus is infected, the risk of postnatal sequelae is 20-25%.
The risk of intrauterine vertical transmission and fetal infection should also be informed to both spouses for pregnant women with recurrent infection is 1%, and if the fetus is infected, the risk of postnatal sequelae is 20%-25%.
Antenatal diagnosis of fetal cytomegalovirus infection should be based on amniocentesis. Amniocentesis should be performed after 21 weeks of gestation and after at least 7 weeks of presumed maternal infection. This time interval is important because it takes 5-7 weeks for the virus to replicate in the kidney after fetal infection before the amount of virus secreted into the amniotic fluid can be detected.
9, In case of recurrent cytomegalovirus infection in pregnant women, amniocentesis can be considered, but the corresponding risk-benefit ratio is not high due to the low rate of vertical transmission.
Once fetal cytomegalovirus infection has been diagnosed, pregnant women should undergo a series of ultrasound examinations every 2-4 weeks to detect sonographic abnormalities. Such sonographic abnormalities help us to predict the prognosis of the fetus, but it should be recognized that the absence of sonographic abnormalities does not ensure a normal fetus.
Quantification of cytomegalovirus-DNA in amniotic fluid can help predict fetal outcome.
Rubella virus screening
1. It is advisable for women preparing for pregnancy to be counseled, have their antibody status determined, and receive rubella vaccination if necessary.
2. Because the risk of congenital rubella syndrome varies with gestational week at the time of infection, it is essential to know the exact gestational week, which is critical for counseling.
3. Primary maternal infection should be diagnosed by serologic testing.
4. Pregnant women who have been exposed to rubella or are symptomatic should have a serologic test to determine immune status and risk of congenital rubella syndrome.
5. Rubella vaccination should not be administered during pregnancy, but is safe after delivery.
6. Careless vaccination in early pregnancy or pregnancy immediately after vaccination is safe for pregnant women because no cases of congenital rubella syndrome have been reported in that setting.
7. Screening for rubella virus during pregnancy should IgG and IgM antibody testing at the same time.
Screening for Toxoplasma gondii
1. All women who are pregnant or planning to become pregnant should be informed in detail about prevention of Toxoplasma gondii infection during pregnancy.
2. Routine universal screening should not be performed in low-risk pregnant women. Serologic screening should be offered to pregnant women who are considered to be at high risk for initial Toxoplasma gondii infection.
3. Pregnant women with suspected recent infection should be tested in a reference laboratory prior to interventional diagnosis, and the test must reflect the infection as accurately as possible and be interpretable.
4. To confirm Toxoplasma infection, PCR should be used to detect Toxoplasma DNA in amniotic fluid in the following cases.
(1) The pregnant woman is diagnosed with a primary infection;
(2) Serologic determination does not confirm or exclude acute infection;
(3) Abnormal ultrasound findings (intracranial calcification, microcephaly, hydrocephalus, ascites, hepatosplenomegaly, or severe intrauterine growth restriction).
5. Amniocentesis should be performed >18 weeks and after 4 weeks of suspected maternal infection to reduce the incidence of false-negative results.
6, Suspected maternal toxoplasmosis infection should be screened with ultrasound to see if the ultrasound results are consistent with TORCH (toxoplasmosis, rubella, cytomegalovirus, herpesvirus, and others) results. This includes, but is not limited to, intracranial calcifications, microcephaly, hydrocephalus, ascites, hepatosplenomegaly or severe intrauterine growth restriction in the fetus.
7. If acute infection is suspected, repeat testing should be performed within 2-3 weeks, taking into account the immediate initiation of treatment with acetylcholine, without waiting for repeat test results.
8, If maternal infection is confirmed but it is not known at this time whether the fetus is infected, acetylspiramycin should be given for prophylaxis of the fetus (to prevent vertical transmission).
9. Pregnant women with confirmed or highly suspected fetal infection (positive amniotic fluid PCR) should be treated with a combination of acetaminophen, sulfadiazine, and formyltetrahydrofolate.
10. Pregnant women who have been infected with Toxoplasma gondii and have been immunized do not need anti-Toxoplasma treatment.
11.Each suspected case of Toxoplasma infection should be discussed with a specialist.
12. Immunosuppressed or HIV-positive women should be screened because of the risk of toxoplasma activation and toxoplasma encephalitis.
13. Pregnant women diagnosed with acute Toxoplasma infection should wait 6 months before becoming pregnant and should consult a specialist in each case.
Herpes simplex virus screening
1. Women should be screened for genital herpes (HSV) infection as early as possible during pregnancy.
2. Women presenting with recurrent episodes of HSV simplex should be informed of the risk of possible transmission of the virus to the newborn during delivery.
In women with primary HSV in late pregnancy, the probability of HSV transmission to the newborn is very high, and clinicians should advise pregnant women to have a cesarean section to reduce the risk of infection.
4. If HSV infection recurs during labor and delivery, cesarean delivery should be performed if there are prodromal symptoms or suspicion of pre-existing functional impairment related to HSV.
5. For recurrent HSV during pregnancy, acyclovir and valacyclovir should be given at week 36 to inhibit viral replication, reduce the probability of lesions, reduce viral transmission, and reduce the rate of cesarean delivery.
6. If a pregnant woman is planning to become pregnant or has no history of HSV infection but her partner has genital HSV infection, serologic tests should be performed before or as early as possible during pregnancy to confirm the diagnosis of HSV infection and should be repeated during the 32nd to 34th week of pregnancy.