Infections In Pregnancy (types, causes, and treatment)
Mar 02, 2023
Infections in pregnancy are common and a serious problem that can have significant consequences for both the mother and the developing fetus. They can lead to maternal complications such as preterm labor, premature rupture of membranes, and chorioamnionitis. They can also result in adverse fetal outcomes such as congenital anomalies, intrauterine growth restriction, stillbirth, and neonatal sepsis.
For NEET PG aspirants it is important to have a thorough understanding of infections in pregnancy, their diagnosis, management, and prevention. Read this blog further to get a quick overview on this important Obstetrics and Gynecology topic for NEET PG exam.
Vertical Transmission
Refers to passage of an infectious agent from mother to her fetus through
The Placenta
During labor or delivery or
Breast feeding
Risk Factors
Preterm rupture of membranes (PROM)
Prolonged labor
Obstetrical manipulations (Like Internal Podalic Version (IPV), Forceps, Vacuum may enhance the risk of Neonatal Infections)
Horizontal Transmission
Spread of an infectious agent from one individual to another
Secondary Attack Rate
Probability that infection develops in a susceptible individual following contact with an infectious person.
Viral Infections
Cytomegalovirus
DNA Herpes virus
MC perinatal infection in the developing world
Up to 85% of poor and 50% of higher classes are seropositive by the time of pregnancy.
Women who develop primary CMV infection during pregnancy [were seronegative before pregnancy], are at greatest risk to have an infected Fetus.
Maternal Infection Features
10-15% of infected adults have
Features of Immuno Compromised
Mononucleosis - like syndrome
Fever, Pharyngitis
Lymphadenopathy
Polyarthritis
Myocarditis, Pneumonitis
Hepatitis, Retinitis
Gastroenteritis or
Meningoencephalitis
Transmission Rates
30-36% in 1st Trimester
30-40% in 2nd Trimester
40-72% in 3rd Trimester
Fetal Infection
(Only 5-10% neonates demonstrate this syndrome)
Features
Complications
Growth restriction, Microcephaly
Intracranial calcifications
Chorioretinitis
Mental retardation, Sensorineural deficits
Hepatosplenomegaly
Jaundice, Hemolytic anemia
Thrombocytopenic purpura
Hearing loss
Neurological deficits
Chorioretinitis
Psychomotor retardation
Learning disabilities
Periventricular Calcification
Diagnosis
Nucleic Acid Amplification Testing (NAAT) of Amniotic Fluid
Gold standard for Dx of Fetal infection
Management
Despite the high infection rate with primary infection in the 1st half of pregnancy, most Fetuses develop normally.
If recent infection is confirmed → Offer Amniotic fluid CMV
Pregnancy termination may be an option for some
Oral Valacyclovir 8gm daily is tried on mother
No Vaccine for CMV is available
Varicella Zoster Infections
90% of adults have serological evidence of immunity
Primary infection → Varicella or Chickenpox
Transmitted by direct contact with an infected individual
Incubation period → 10 to 21 days
1 to 2 days flu like prodrome followed by Pruritic Vesicular lesion that crust after 3 to 7 days
Period of communicability → 1 day before the onset of rash until lesions become crusted
Maternal Mortality
Predominantly d/t VZV (Pneumonia) in pregnancy
Risk Factors - Smoking, > 100 cutaneous lesions point towards poor prognosis
If there is reactivation of primary Varicella years later, it leads to Herpes Zoster or Shingles
U/L dermatomal Vesicular eruption
a/w severe pain
not more frequent or severe in pregnant women
Congenital Varicella syndrome rarely develops in cases of Maternal Herpes Zoster
After 20 weeks of gestation, no clinical evidence of Congenital infection
Around Delivery
Active infection just before or during delivery (before Maternal antibody formed) is a serious threat.
Neonatal mortality rate is 30%
Disseminated Visceral & CNS disease is commonly fatal.
Important Information
Varicella Zoster Immunoglobulin (VZIG) should be administered to neonates born to mothers who have clinical evidence of Varicella - 5 days before & up to 2 days after delivery.
Diagnosis OF Varicella
Maternal
Clinical diagnosis
Confirmed by NAAT of vesicular fluid
Scraping the Vesicle base & go for Tzanck smear, Tissue culture or Direct Fluorescent antibody testing
Fetal
Congenital Varicella Dx with NAAT of Amniotic fluid
Management
Maternal Exposure
Exposed pregnant women who are seronegative should be given VZIG
Best given with in 96 hrs of exposure
Can given up to 10 days
Established Maternal Infection
IV ACYCLOVIR therapy (at 10-15 mg/kg every 8 hrs.) with hospitalization.
Influenza
Pregnant women are more susceptible to serious complications especially d/t Pulmonary Involvement.
Orthomyxoviridae → RNA virus → both Influenza A & B cause Epidemics
Influenza A is not related with congenital malformations
Viremia is infrequent
Transplacental passage is rare
Abortion, Preterm labor, Stillbirth - all reported, but more d/t severity of maternal infection.
Nasopharyngeal Swabs
Reverse transcriptase PCR → Most sensitive & specific test
Rapid Influenza Diagnostic Test (RIDT) → Least sensitive & least indicative
Treatment
Neuraminidase Inhibitors
Oral Oseltamivir for prophylaxis
Zanamivir inhalation for treatment
Measles & Mumps
Not Teratogenic
RUBELLA/ GERMAN MEASLES
RNA Togavirus
Maternal Infection
Mild febrile illness
Generalized maculo - papular rash on face & trunk
25-50% are asymptomatic
Diagnosis
ELISA
IgM antibody detected within 4-5 days of onset of infection
IgG peaks 1-2 weeks after rash
High avidity IgG antibodies indicates infection was at least 2 months prior to tests done.
Most complete Teratogen
Worse during Organogenesis (1-12 wks of pregnancy)
Mother to child transmission
1st trimester: MTCT → 90%
2nd trimester: MTCT → 50%
End of 2nd trimester: MTCT → 25%
High Avidity IgG Antibodies
Avidity is the strength of bond of Antibody with Host Cell. i.e. how much strong is the bond
Loose bond = Low Avidity = Recent infection
Strong bond = High Avidity = Remote infection
Done to differentiate Recent positive IgG from Remote positive IgG
If IgG is positive for long time (Remote positive IgG)↓
Mother is immune to Rubella & problems in fetus are not likely to happen
Recent positive IgG (Both IgG & IgM positive)↓ Baby may be affected
Congenital rubella syndrome
Features
Cardiac septal defects
Pulmonary stenosis
Microcephaly
Cataract
Hepatosplenomegaly
Sensorineural deafness
Intellectual disability
Neonatal purpura
Radiolucent bone disease
Neonates with congenital rubella may shed the virus for many months (threat to others)
Can try Passive immunization within 5 days of exposure
MMR vaccine to all non pregnant women
Avoid vaccine within 1 month of planning the pregnancy or during pregnancy (as it contains live attenuated virus which can cause defects in fetus)
Vaccines In Pregnancy
Contraindicated
Safe
Measles
Mumps
Rubella
Varicella
BCG
Tetanus & Diphtheria toxoids (Tds)
Hepatitis B
Influenza
Meningococcal
Rabies
Anthrax, Hepatitis A, Japanese Encephalitis, Polio IPV, Yellow Fever are given on special recommendation
ZIKA Virus
1st mosquito borne teratogen
Daytime Aedes mosquito bites
Family = Flaviviridae
May have sexual transmission
Maternal Infection
Rash, Fever, Headache, Arthralgia, Conjunctivitis
Neurological complications
Guillain - Barre syndrome, Neuropathy & Myelitis
Fetal Infection (Fetus can be severely affected)
Birth defects (5-15%)
Neonatal Deaths (5-7%)
Congenital Zika Syndrome
Microcephaly
Lissencephaly
Ventriculomegaly
Intracranial calcifications
Ocular abnormalities
Congenital contractures
Diagnosis in pregnant women
ZIKA virus in blood & urine
Do Serological testing & confirm by PCR
No specific treatment or vaccine of ZIKA so far
Protozoal Infections
Toxoplasmosis
Feline stage in cats
Non feline stage in Humans
Infection is with cat faces or infected meat ingestion
MTCT of Toxoplasmosis
Rises with increasing gestational age 1
1st trimester : 15%
2nd trimester: 44%
3rd trimester: 70%
Clinically Affected Fetuses have
Low birth weight
Hepatosplenomegaly, Jaundice, Anemia
Neurological diseases with Intracranial calcification, Hydrocephalus, Microcephaly often accompanied by convulsions
Classical Triad
Chorioretinitis
Intracranial calcifications
Hydrocephalus
Diagnosis
IgG before pregnancy → No risk
IgM: appear by 10 days of infection
Best results are obtained with the Toxoplasma serological profile
Toxoplasma IgG avidity increases with time
If high - avidity IgG result is found, infection in the preceding 3-5 months is excluded
Treatment
Goal of Rx is reduction in rates of serious Neurological sequelae & Neonatal demise
Spiramycin alone (does not cross placenta)
Pyrimethamine - Sulfonamide with Folinic Acid (If Fetal Infection is suspected)
Prevention
Cooking meat to safe temperatures
Peeling or thoroughly washing fruits & vegetables
Cleaning all food preparation surfaces
Wearing gloves when changing cat litter
Avoiding feeding cats raw or undercooked meat & keeping cats indoors
Malaria In Pregnancy
Pregnant women have increased susceptibility
VAR2CSA antigen leads to Antibody formation, which causes accumulation of infected erythrocytes in the placenta, leading to Pregnancy specific Antimalarial immunity
Higher rates of Maternal Morbidity & Mortality
Worse in pregnancy
Fetal Infection
Abortions
Still birth
Preterm birth
Low birth weight
Congenital malaria (< 5% incidence)
Diagnosis
Thin & Thick films (Best method)
Malaria -specific antigens are used for Rapid diagnostic testing but their sensitivity in pregnancy is still an issue
Anemia is usually same in pregnant women with Malaria d/t significant amount of Hemolysis
Treatment
Uncomplicated malaria by P. vivax, P. malariae, P. ovale, Chloroquine sensitive Falciparum malaria
Chloroquine or Hydroxychloroquine
Complicated P falciparum malaria - Artemisinin based regimens
Chloroquine resistant P. Vivax - Mefloquine
HIV In Pregnancy
Mostly by HIV – 1 infection
Transmitted by
Sexual intercourse
Blood transfusion/ Infected needles
During labor & delivery
Breast milk
Primary determinant of transmission → Plasma HIV - 1 viral load
CD4 site serves as a receptor for virus
Once infected, CD4 lymphocytes may die
Illness with AIDS is d/t profound immunodeficiency that gives rise to various opportunities infections and neoplasms
According to CDC, ‘AIDS’ is
CD4 T cell count < 200 cells/µl
CD4 T cell count comprising < 14% of all lymphocytes or
One of several AIDS - defining illness
Screening
HIV screening using an OPT-OUT approach
Repeat testing during 3rd trimester is considered for all pregnant women
No cases of vertical transmission with maternal viral load <50 copies/ml at delivery
Timing of transmission
20% of vertical transmission occurs before 36 weeks
50% in the days just before delivery (i.e. 38-39 wks)
30% Intra-partum
Breast feeding MTCT may be as high as 30-40%
Caution
Didanosine, Stavudine & full dose of Ritonavir are avoided in pregnancy as they are Toxic to mother (not Teratogenic)
Antiretroviral naive patients are given ART regardless of trimester
In general, the starting regimen comprises
2 Nucleoside Reverse transcriptase inhibitors Plus
Either a Ritonavir boosted protease inhibitor or an Integrase inhibitor
Full dose of Ritonavir is C/I in pregnancy due to its toxicity but Ritonavir boosted protease inhibitors can be given
Recommendations
Taking ART & pregnant ? Continue current drugs
All women get ART ASAP? Monitor CD4 count at initial and then 3 monthly visits
ART Naive
2 NRTI
Abacavir / Lamivudine
Tenofovir Disoproxil Fumarate / Emtricitabine
And a Protease Inhibitor
Atazanavir / Ritonavir
Or an Integrase Inhibitor
Raltegravir
Oral ART during pregnancy + IV Zidovudine during labor can reduce MTCT to < 2 %
Intrapartum Care
As per NACO & WHO guidelines, there is no benefit of Cesarean section over NVD (Normal Vaginal Delivery)
C-section is done only in Obstetric indications in an HIV pregnancy
For HIV RNA > 1000 copies / ml, we can reduce MTCT by giving 2 mg / kg ZDV IV as loading dose then 1 mg/kg hourly till delivery
For C-section, start IV dose 3 hours prior
Antiretroviral Therapy
Ideal strategy to suppress viral load & minimize Vertical transmission includes
Preconceptional ART
Ante-partum ART
Intrapartum continuation of Ante-partum Oral ART regimen plus IV Zidovudine
Newborn ART prophylaxis
PPH in HIV women
Best managed with Oxytocin and Prostaglandin analogues
Methylergonovine (Methergine) and other ergot alkaloids adversely interact with Reverse transcriptase inhibitors and Protease inhibitors to cause severe vasoconstriction.
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