Which of the following infection is most teratogenic during pregnancy?

NORCET-7 Mains-2024

Obstetrics & Gynaecology

Medium

Appeared in: NORCET-7 Mains-2024

Explanation

Zika virus is a potent teratogen that can be transmitted from mother to fetus during pregnancy.
Infection, especially during the first trimester, is directly linked to a pattern of severe birth defects known as Congenital Zika Syndrome.
The most notable defect is microcephaly, an abnormally small head and brain, caused by the virus targeting and destroying fetal neural progenitor cells.
Other features of the syndrome include brain calcifications, eye abnormalities, and congenital contractures.

Option A: While Herpes Simplex Virus (HSV) can be transmitted to the fetus, the most significant risk is perinatal transmission (during delivery), leading to neonatal herpes. Congenital (in-utero) transmission is much rarer and not as consistently associated with a specific pattern of severe structural defects as Zika.
Option B: The influenza virus itself is not considered a direct teratogen. The main risk to the fetus from maternal influenza infection is the associated high fever (hyperthermia), which has been linked to an increased risk of neural tube defects and other anomalies. The effect is indirect.
Option D: Current evidence does not establish SARS-CoV-2 (the virus causing COVID-19) as a major teratogen. While maternal infection can lead to adverse pregnancy outcomes like preterm birth or low birth weight, it has not been linked to a consistent pattern of specific congenital malformations like Zika virus.

Visual 1: Infographic - A comparative chart showing the different outcomes of Congenital Zika Syndrome, Congenital Rubella Syndrome, and Neonatal Herpes to highlight the distinct effects of each virus.
Visual 2: Illustration - A diagram showing the Zika virus crossing the placental barrier and targeting the developing fetal brain, leading to microcephaly.
Visual 3: Photograph - An image comparing the head circumference of a healthy newborn with that of a newborn with severe microcephaly caused by Zika virus.

Clinical Relevance

Nursing practice connection: Knowing Teratogenic effects of viral infections during pregnancy helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must include travel history assessment (to Zika-endemic areas) and counseling on mosquito bite prevention for all pregnant women and those planning pregnancy.
Educating patients about the TORCH infections is a key part of antenatal care. While the acronym is historical, it's a useful starting point for discussing congenital infection risks.
Fever in pregnancy, regardless of the cause, should be managed promptly with antipyretics like acetaminophen to reduce the indirect teratogenic risk of hyperthermia.

How to Approach the Question

First, understand the key term 'teratogenic', which refers to any agent that causes an abnormality following fetal exposure during pregnancy.
The question asks for the 'most' teratogenic infection among the choices, implying a need to compare the severity and directness of their effects.
Evaluate each option: Recall or deduce the known effects of each virus on a developing fetus.
Herpes (HSV) is primarily a risk at birth. Influenza's risk is mainly from fever. COVID-19 is not established as a major teratogen.
Zika virus is famously and directly linked to a severe and specific birth defect, microcephaly (Congenital Zika Syndrome).
Conclude that Zika virus has the most direct, severe, and well-defined teratogenic effect among the given options.

Concept Tested & Keywords

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