WBR0082

Author	[[PageAuthor::Aditya Govindavarjhulla, reviewed by user: Jad Al Danaf]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Reproductive
Prompt	[[Prompt::A 26 year old woman in her 16th week of pregnancy presents to the office for a routine visit. She gives a history of coming into contact with a 2 year old child who had german measles. At what time during her pregnancy is she at highest risk of transmitting the virus to the fetus to cause congenital rubella syndrome?]]
Answer A	AnswerA::Preconception
Answer A Explanation	AnswerAExp::If infection occurs within 0–28 days before conception, there is a 43% chance the infant will be affected. This is not the period during which the patient is at highest risk.
Answer B	AnswerB::First trimester
Answer B Explanation	AnswerBExp::If the infection occurs within 0–12 weeks after conception, there is a 51% chance the infant will be affected. The first trimester is the time period during which the patient is at highest risk of transmitting rubella to her infant.
Answer C	AnswerC::Second trimester
Answer C Explanation	AnswerCExp::If the infection occurs within 13–26 weeks after conception there is a 23% chance the infant will be affected by the disease. This is not the trimester during which the patient is at highest risk.
Answer D	AnswerD::Third trimester
Answer D Explanation	AnswerDExp::Infants are not generally affected if rubella is contracted during the third trimester, or 26–40 weeks after conception.
Answer E	AnswerE::
Answer E Explanation	AnswerEExp::
Right Answer	RightAnswer::B
Explanation	[[Explanation::Rubella is a viral illness caused by a togavirus of the genus Rubivirus and is characterized by a mild, maculopapular rash. When rubella infection occurs during pregnancy, especially during the first trimester, serious consequences can result. These include miscarriages, fetal deaths/stillbirths, and a constellation of severe birth defects known as congenital rubella syndrome (CRS. Children usually develop few or no constitutional symptoms, but adults may experience a 1–5-day prodrome of low-grade fever, headache, malaise, mild coryza, and conjunctivitis. Postauricular, occipital and posterior cervical lymphadenopathy is characteristic and precedes the rash by 5–10 days. Arthralgia or arthritis may occur in up to 70% of adult women with rubella. In pregnancy, the rubella virus travels through the blood stream of the fetus and damages the blood vessels, after transmission from the mother during the viremic stage of the infection. This results in ischemic injury to the cells in the germ layers. The risk of congenital infection and defects is highest during the first 12 weeks of gestation, and decreases after the 12th week of gestation with rare defects after the 20th week of gestation. If infection occurs within 0–28 days before conception, there is a 43% chance the infant will be affected. If the infection occurs within 0–12 weeks after conception, there is a 51% chance the infant will be affected. If the infection occurs within 13–26 weeks after conception there is a 23% chance the infant will be affected by the disease. Infants are not generally affected if rubella is contracted during the third trimester, or 26–40 weeks after conception. Educational Objective: References: ]]
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