Embryology · Teratology and prenatal diagnosis
Congenital rubella syndrome !
- Teratogen
Rubella early in pregnancy can leave the baby with cataracts, deafness and heart defects; vaccination before pregnancy prevents it.
Updated 2026-11-01
See it in 3D: Lens · Cochlea · Retina · Ligamentum arteriosum · Pulmonary trunk
What it is
Rubella is a mild viral illness in adults, but if the mother is infected early in pregnancy the virus crosses the placenta and damages forming organs. Congenital rubella syndrome combines eye, ear and heart defects with other problems. It was the first infectious teratogen recognized and is prevented by vaccination before pregnancy.
Key facts
- Other eye findings: glaucoma, microphthalmia and 'salt-and-pepper' retinopathy.
- Many babies look well at birth and later show deafness, endocrine problems (diabetes, thyroid) or developmental problems.
- Maternal infection can also cause miscarriage or stillbirth.
- After MMR vaccination, waiting at least four weeks before trying to conceive is advised.
Critical period and mechanism
- Critical period: first trimester, especially the first 12 weeks, when the lens, inner ear and heart form.
- The virus infects the placenta and then embryonic tissues.
- Infected cells divide less and vessel endothelium is damaged, leaving organs with fewer cells.
- Later in pregnancy the risk of malformations falls sharply.
Prevention
- MMR vaccination of girls and women before pregnancy.
- Checking rubella immunity at the preconception visit.
- The vaccine is not given in pregnancy; unvaccinated women receive it after delivery.
What it does to the embryo and fetus
- Eyes: cataracts, glaucoma, microphthalmia, pigmentary retinopathy.
- Ears: sensorineural deafness, the most frequent finding and sometimes the only one.
- Heart: patent ductus arteriosus and pulmonary artery branch stenosis.
- Growth restriction, hepatosplenomegaly, thrombocytopenia with purpuric rash and intellectual disability.
Test yourself
Think of the answer, then tap the question to see it.
What is the classic triad of congenital rubella syndrome?
Cataracts, sensorineural deafness and congenital heart disease, typically patent ductus arteriosus.
When in pregnancy does rubella cause the most severe defects?
In the first trimester, especially the first 12 weeks.
Why is the MMR vaccine not given during pregnancy?
It is a live attenuated vaccine; it is given before pregnancy or after delivery.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- TORCH infections: what each agent does to the embryo and fetus
- Patent ductus arteriosus
- Coloboma, congenital cataract and congenital glaucoma
- Congenital hearing loss, microtia and preauricular pits
- Eye: optic vesicle, optic cup and lens
- Ear: inner, middle and external ear
- Principles of teratology: critical periods, dose and genotype
Related conditions
- Congenital (TORCH) infections: syphilis, toxoplasmosis, CMV and Zika
- Hearing loss (conductive and sensorineural, including sudden hearing loss)
- Cataract
- Patent ductus arteriosus
Microorganisms
Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.
Sources: Pregnancy and Rubella (CDC, 2024); About Rubella (CDC, 2024); Embryology, Teratology TORCH (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.