Chauhan AR
Maternal infections have been associated with pregnancy since time immemorial, be it the ubiquitous throat infection or full-blown septicemia; however despite pregnancy being an “immune-compromised state”, maternal response to infections in pregnancy is usually the same as in non- pregnant adults. Some infections may be more dangerous in pregnancy and have short and long-term devastating sequel like pregnancy wastage, preterm labor, fetal death, and maternal -fetal transmission leading to lifelong stigmata.
Infections in pregnancy may be classified based on the route of infection and type of organism (viral, bacterial, protozoal). However the diagnostic approach is usually based on symptomatology, gestation age and immune status of the mother. Both humoral and cell mediated immunity have a significant role; the former tackles extracellular pathogens and the latter, intracellular pathogens. Pregnant women may be at risk, exposed to, or contract a viral fever with rash, where the management varies from simple observation and counseling to medical termination of pregnancy, for example in cases of rubella in first trimester.
Infections usually have a “vertical transmission”, a term that refers to the unique relationship between mother and fetus. Transmission may be intrauterine (transplacental), perinatal (just prior to or during delivery via hematogenous route or genital tract), or postnatal through breast milk. Viruses like rubella, cytomegalovirus (CMV), varicella zoster, HIV and parvovirus, bacteria like syphilis, and protozoans like toxoplasma and malaria are all transmitted via the placenta, while herpes simplex virus (HSV) and group B streptococcus (GBS) usually ascend through the genital tract and infect the fetus.
The exact impact on pregnancy varies widely: maternal reactions like high fever and anemia can precipitate embryonic demise; teratogenicity may occur if fetal insult occurs early in first trimester; non- specific fetal problems like IUGR, hydrops, and microcephaly may be seen later in pregnancy with a number of viral infections.
Congenital infections may be transmitted in any trimester, but in general, fetal affectation is more severe when the infection is acquired early in pregnancy, resulting in abortion, fetal loss or teratogenicity; rubella infection is a classic example with a well-defined syndrome of congenital malformations. Fortunately the risk of transmission of infections is low in early gestation. Conversely, though the rates of fetal infection are higher in later gestation, the effects are not as severe and manifest as IUGR or developmental anomalies.
Routine antenatal screening at the first prenatal visit using a battery of tests may appear ideal, but is neither feasible nor routinely possible. A viable compromise between the potential dangers of infection, resources available for testing and maternal willingness for the same should be reached; the standard minimum screen should include rubella IgG, hepatitis B surface antigen, and serological tests for syphilis and HIV.
Ideally, rubella non-immune women should be offered vaccination prior to conception, or if screened during pregnancy, they should be counseled about viral fevers and rash, especially in the first trimester. Current recommendation is to offer measles – mumps –rubella (MMR) vaccine postnatally. Infants born to hepatitis B positive mothers should be actively and passively immunized at birth to decrease the risk of development of carrier state. Syphilis is still an infection to be reckoned with; if untreated, there is an alarmingly high perinatal mortality of 40% (25% of affected pregnancies result in stillbirth and 14% in neonatal deaths). Despite WHO guidelines, syphilis screening is not done in many underdeveloped countries with disastrous fetal consequences. Penicillin remains the drug of choice.
In the absence of any intervention, the risk of transmission of HIV from mother to child is about 25- 30%; this can be reduced significantly to about 12% with treatment. National AIDS Control Organization (NACO) recommends single dose nevirapine during labor in treatment-naïve pregnant women with CD4 count >250cells/mm3. For HIV positive pregnant women already on antiretroviral therapy, their existing regimen should be continued; efavirenz however should be avoided in the first trimester due to teratogenicity.
TORCH is an acronym for congenital infections: Toxoplasmosis, Other infections (syphilis, hepatitis B, Coxsackie virus, Epstein-Barr virus, varicella-zoster virus, and human parvovirus), Rubella, CMV and HSV. TORCH infections are usually the cause of isolated fetal loss and not recurrent losses, as is mistakenly believed. Routine screening is not recommended except for rubella IgG, and CMV screening for women who work in neonatal ICUs, child care facilities or dialysis units.
Diagnosis of TORCH and other infections is based on maternal symtomatology and serology. Flu- like symptoms with fever, myalgia and lymphadenopathy may point to primary CMV or toxoplasma infection, or listeriosis, if associated with diarrhea. Listeriosis is an uncommon foodborne illness which can be prevented with simple advice like meticulous washing of raw food, adequate cooking, and hand washing. Presence of maculopapular rash along with fever and arthralgia should raise the suspicion of rubella or parvovirus infection. Parvovirus infection causes erythema infectiosum, and is responsible for fetal loss and hydrops; intrauterine transfusion greatly improves the fetal outcome. Varicella rash is usually a typical vesicular rash and the diagnosis is clinical. Urinary tract infection, HSV, gonorrhea and Chlamydia should be ruled out when patients present with genitourinary symptoms, loin pain, fever, genital ulcers and vaginal discharge. Varicella and herpes infection in pregnancy may warrant treatment with acyclovir, which though not routinely recommended in pregnancy, may be used to reduce maternal morbidity. Patients with HSV infection at term should be delivered through cesarean section to avoid the risk of neonatal sepsis and encephalitis, which may be fatal.  Fetal diagnosis of infection may be confirmed with chorion villous sampling or amniocentesis in select cases.
Malaria is endemic in many parts of India and pregnancy with malaria is associated with an increased parasite density and severity of disease, especially in the first part of pregnancy. Prophylactic antimalarials and insecticide –treated nets are recommended in endemic areas.
The vicious cycle between maternal infection and preterm labor, as both cause and result, has been well documented. Infections like bacterial vaginosis, gonorrhea and chlamydia increase the risks of preterm labor and premature rupture of membranes. Treatment with antimicrobials may improve fetal outcome by decreasing chances of chorioamnionitis and hence neonatal sepsis and NICU admission.
Infections of the urinary and reproductive tracts during pregnancy are likely to be underplayed by both the patient and her obstetrician. UTI, bacterial vaginosis and asymptomatic bacteriuria may have far- reaching consequences for both mother and fetus, ranging from mild fever and  discomfort to pyelonephritis,  higher incidence of PROM and subsequent chorioamnionitis, and neonatal septicemia. During delivery, GBS infection of the reproductive tract can transmit and manifest as neonatal sepsis. Hence adequate antibiotic prophylaxis and treatment are indicated.
Maternal periodontal disease is emerging as a new preventable infection associated with preterm deliveries and low birth weight babies; however evidence is conflicting. Improvement in standards of periodontal care and treatment during pregnancy may help combat this trend.
Other emerging infectious diseases include the not so recent scare of SARS (severe acute respiratory syndrome), viral hemorrhagic fevers like Lassa fever and Ebola which are more severe in pregnancy, and Psittacosis, a flu-like illness with fever, headache, and atypical pneumonia. Pneumocystis jiroveci, previously known as Pneumocystis carinii, responsible for pneumonia in immune-compromised patients, may be more severe in pregnancy and vertically transmitted by HIV-positive patients to their offspring.
It is these emerging infections against which we need to be well informed and vigilant, so as to provide adequate protection to our expectant mothers and their unborn babies. It gives me great pleasure to present to you the June issue of our Journal, which features an interesting case of HSV in pregnancy.