During which period is the risk of Rubella highest for fetal development?

The risk of Rubella for fetal development is highest during the period from the 5th to the 16th week of gestation. This timeframe is critical because it encompasses the organogenesis stage, where major organs and structures are forming. Infection during this period can lead to severe congenital defects, such as congenital heart defects, deafness, and cognitive impairments, among others, collectively known as congenital rubella syndrome.

During the first four weeks of gestation, the embryo is at a stage where it may not yet be susceptible to infection effects in a measurable way, as significant organ development has not yet occurred. After the 16th week of gestation, the risks associated with Rubella exposure decrease significantly, as the major structures and organs are already formed, and the immune system of the fetus begins to develop and respond to infections.

Therefore, the highest risk correlates specifically to the critical period of organ development, aligning with the time frame from the 5th to 16th week of gestation. Understanding this risk period is crucial for counseling and preventive measures in pregnant women and those planning to conceive.