*Q1* *How to avoid Rubella Infection* ?
It’s a good practice point to *screen every woman with Rubella IgG* who wishes to become pregnant (UK does it, France and Austria also screen for Toxoplasmosis.
Obviously a *positive Rubella IgG indicates past infection and hence immunity* and these women can safely Plan for pregnancy.
However *Rubella IgG negative women should be offered Rubella Vaccine* (R-Vac, 0.5ml, Serum Institute, Rs 70/-) following which a *minimum of One month (Maximum three months) should be waited for before pregnancy.*
*If a woman is seen directly in pregnancy, Even then screening for Rubella IgG is recommended* along with HBSAg, HCV, VDRL and HIV and IgG positive woman should be reassured.
However Rubella IgG negative women *in pregnancy can’t be offered Rubella vaccine (Live attenuated virus)* and therefore should be advised to *refrain from coming in contact with* any Known Rubella Infected person, Kids, Person with Cough and cold etc.
*Q2* *What is to be done in Women with a suspicious History of contact with Rubella* ?
*Understanding the SEROLOGY is the key note*
Rubella infection is diagnosed by serology. For pregnant woman who is Rubella IgG negative and comes to you with a suspicion of coming in contact with Infected Rubella or has a clear signs and symptoms of Rubella ( lymphadenopathy , erythematous rash and low-grade fever) , *three serology tests are helpful: IgG, IgM and Avidity:*
*Remember IgM indicates acute infection or a rare re-infection* . It starts to build up in serum in 5-7 days and vanishes after 6 months. IgM serology done within 5 days can come negative and hence should be repeated to confirm.
*IgG also starts to build up after 7 days and generally is life long after that*
IgG avidity is done to see its strength of attachment to antigen : *In recent (less than 3 months) this attachment is weak and the Avidity comes low*
*In older infections (more than 6 months) IgG attachment comes strong, Avidity is high*
Three categories of serology is expected:
*Scene 1 : IgM +ve and IgG -ve*
This indicates recent infection however a repeat serology for confirmation within 14-21 days (minimum 7days ) is highly recommended : if positive needs termination if GA < 12 weeks
*Scene 2: IgM +vE and IgG +vE*
This can be Acute infection (Remember after 7 days both IgM and IgG can appear), or Re infection or Old infection of just 6 months (where IgM are disappearing).To differentiate between these scenarios, we need to do IgG Avidity.
If Avidity is strong that means this IgG is indicating Old infection and hence positive IgM in this case is either Re-infection (which very rarely is problematic to fetus) or a 6 months old infection with IgM disappearing but not completely gone out of the blood ( again no problems to the fetus.
If avidity is weak, It indicates a recent infection within three months and hence can cause problems to the fetus .Counsel for termination if GA < 12 weeks. if gestation > 12 weeks Amniocentesis for Rubella RNA PCR from amniotic fluid is recommended.Alternatively cordocentesis (Fetal Blood sampling) for IgM can also be done.
*Scene 3 : IgM -ve and IgG +ve*
This generally indicate an Old infection ( indicating immunity) but doing IgG avidity is still strongly recommended.
*Q3* : *Chances of Fetal* *affection and how to diagnose it and what’s the management plan* ?
Remember a maternal infection does not mean Fetal infection and a fetal infection doen not necessarily mean Congenital Defect or syndrome. *If the maternal infection has happened before 12 weeks of gestation, the risk of fetal infection is 90% with the risk of developing any rubella associated congenital defects as high as 90%.* The risk of fetal infection is about 55% at 12–16 weeks and congenital defects at 20% .However after after 16 weeks although the risk of fetal infection is still 45% but Risk of congenital defect low with only concern being sensori-neural deafness.
Based on above statement, *if a proven maternal Rubella infection occurs before 12 weeks (where there are 90% chance of fetal affection and 90 % chance of congenital abnormality) Termination is the best answer.*
*For an infection occurring after 12 weeks, best way to assess fetal affection is by Amniocentesis to check reverse transcriptase PCR (RT-PCR)* for the detection of viral nucleic acid in amniotic fluid. In cases where RT-PCR comes positive indicating fetal affection (controversial though) a Termination can be advised. For patients who are keen on pregnancy and not willing for termination can be monitored by serial monthly ultrasounds and a foetal echocardiography at 22 weeks.
Remember some guidelines *recommend screening for Parvovirus IgG and IgM* in every suspected case of Rubella as clinical presentation of both is similar and disguise.