Infections in Pregnant Women - Role of Diagnostic Microbiology

INFECTIONS IN PREGNANT WOMENA routine test done in every pregnant woman
Role of Diagnostic Microbiologyirrespective of consent is associated with biological
Dr. T.V.RAO M.Dfalse positives. Every positive test should be
DEPARTMENT OF MICROBIOLOGYreconfirmed testing with TPHA, a specific test to
Pregnancy is a dynamic state of health and disease,detect active infection. Testing with FTAbs IgG
shared by the pregnant woman and a growing fetus,remains the best option before diagnosis of syphilis is
a concern to the treating physician for timelyruled out.
diagnosis and necessary interventions. Infections withBACTERIAL INFECTIONS IN PREGNANT WOMEN
Viral, Bacterial, Parasitic and Fungi do occur in anyMany bacterial infections have Major effect on
pregnant woman like other non pregnant woman ofwomen’s health with implications on the New
similar age. Most infections are not serious. But someborn.
infections are more important in pregnant womanURINARY TRACT INFECTIONS
than in non pregnant woman because of the potentialUrinary tract infections remain the most common
for vertical transmission to foetus or infant. There isinfections at any stage of pregnancy. Many present
a growing awareness on HIV, HBV, CMV, Rubella andwith asymptomatic infections, Asymptomatic
Toxoplasmosis, on rare occasions Varicella andbactenuria which can only be identified on culturing
Listeriosis can do harm to the growing foetus. Withthe urine. It is ideal to order culturing in early
advances in medical treatments and laboratorypregnancy to be followed upto the last trimester of
technologies we are more concerned withpregnancy. Most neglected part of urine culturing
transmission of HIV, and HBV as we can still interfereremains with proper collection of specimen and often
with appropriate treatments. Now it is certain, everyleft to an inexperienced nursing staff. The treating
pregnant woman needs a successful screening forphysicians should instruct the staff how to collect a
Rubella IgG, HBV surface antigen, and HIV antibodiesmid stream and a clean catch sample. Less
apart from existing protocol for screening for Syphilisexperienced Microbiologists give confusing reports but
in all pregnant women with VDRL / RPR testing.should not forget to specify the validity of report. A
WHY GOOD CLINICAL MICROBIOLOGY SERVICEScut off point of ? 100,000 bacteria/ml is the minimal
ARE IMPORTANTcriteria in healthy pregnant women with isolation of a
No laboratory test for diagnosing a specific diseasesingle species e.g. E.coli, Klebsiella species will
should be undertaken on a casual testing basisstrengthen the diagnosis of urinary tract infections.
without knowing the implication of a positive value ofMissing of asymptomatic bacteriuria can cause
test. Women are more willing to accept routinelypremature labor and pylonephritis in pregnant women.
offered testing as in screening for syphilis with. TheGROUP-B STREPTOCOCCAL INFECTION
situations to screen for antibodies to HIV turn to beThere is a growing awareness on infections with
entirely different and needs an informed consent, asGroup B Streptococci. CDC advices culturing for
every woman has a right to refuse any medicalStreptococcus B group at 35-37 weeks of pregnancy
investigation or treatments.is important which can help to prevent early neonatal
UNDERSTANDING MICROBIOLOGY REPORTS WITHinfection particularly premature labor. Appropriate
IMPLICATIONS ON FETAL HEALTHcollection of specimen from cervix remains the
There is an unlimited gap of understanding betweenminimal requirement.
the laboratory reports and the treating physician,GONOCOCCAL AND CHLAMYDIAL INFECTION
which should be always brought down for improvingThey need specific or specialized techniques for
our quality of services.precise diagnosis but only ordered in high risk group
1. All requests for any particular serological orof women as they can lead to pelvic inflammatory
molecular testing should be based on clinicaldiseases. The physician should discuss with clinical
symptoms (May not necessary as in HIV, HBV, CMVmicrobiologist as routine testing is not possible in less
and Syphilis which are symptom free in early stages.)equipped laboratories and will not serve the purpose
2. Writing a good clinical history will certainly guide theBACTERIAL VAGINOSIS AND CANDIDIAL
testing clinical microbiologist to use the right protocolINFECTIONS
in the laboratory methods.eg. Toxoplasmosis, CMV,There is a growing incidence of Gardnernella vaginalis
Rubella to determine the active infection.and Candidial infection. Few laboratories have
INTERPRETATION OF RESULTS RUBELLA, CMV,adequate facilities for characterization of etiological
TOXOPLASMOSIS, VARICELLA Infections.agents. The clinical requests should specify what they
1. Clinicians should request for IgG in all cases apartare looking for.
from IgM which is only positive in recent infections.Today we have an ever growing list of microbes
2. Best serological evidence of recent infections isincluding Varicella, Herpes simplex, Parvovirus B19,
IgG seroconversion (a change from a negative testListeriosis and many others encroaching on pregnant
to positive test) to understand all serological testswomen. An appropriate investigation and
which turn out to be negative on first testing, do notmanagement can reduce adverse outcome,
exclude recent infections. Testing should be repeatedunnecessary interventions and anxiety. The need of
upto three weeks after suspected contact, whichthe hour in up gradation of our Microbiology
may be extended up to 6 months in cases oflaboratories to cope, with changing trends in infection
diagnosis of HIV Infection for appearance ofas there is ever-increasing list of Microbes harming a
antibodies.pregnant women and the growing fetus.
3. When a specific IgM is positive without IgG beingCAUTION ON MOLECULAR METHODS
positive results should be interpretated with caution.All molecular methods for diagnosis of infectious
If Ig G seroconversion do not occur the IgM result isdiseases ordered with caution. It is ideal to try all time
likely to be a false positivetested laboratory methods and to consider the using
4. The question comes how recent is infection: canof molecular methods which on many occasions are
be clarified with newer generation of serologicalresearch or academic tools with good number of
testing in accredited laboratories. The clinicians shouldfalse positive reactions.
ask for IgG avidity assays which will help confirm orIn spite of several advances in Laboratory
exclude recent infection. ( Eg , Toxoplasmosis, RubellaTechnologies in Developing countries, we in India
and CMV ) As high avidity indicates that infectionmust depend on the wisdom of our Physicians, as
occurred several months previously. Interpretationour patients do not afford many investigations on
depends on laboratory protocols and should berandom basis or for Academic interest. However,
discussed with clinical microbiologists.antenatal screening that is not based on accepted
HIV SCREENING OR TESTINGcriteria or well defined plan of action can cause
The problems of screening all pregnant women forunnecessary anxiety and potentially dangerous
HIV antibody is a complex issue. It should beintervention. Still we know little how a Fetus protects
discussed and issue can be still be resolved if offeredand survives itself in spite of several challenges apart
as testing with motive of offering antiretroviralfrom Infections.
therapy to both mother and new born if infected.Email; tvraodoctor2000@yahoo.co.
SCREENING FOR SYPHILIS (WITH VDRL/RPR)