Chickenpox to the fetus. Varicella infection in pregnant women could lead to spread via the placenta and infection of the fetus. If infection occurs during the first 28 weeks of gestation, this can lead to fetal varicella syndrome (also known as "congenital varicella syndrome"). Effects on the fetus can range in severity from underdeveloped toes and fingers to severe anal and bladder malformation. Possible problems include: Infection late in gestation or immediately following birth is referred to as ""neonatal varicella"". Maternal infection is associated with premature delivery. The risk of the baby developing the disease is greatest following exposure to infection
Contagious disease illustrated classically by tuberculosis, which is clearly transmissible from person to person, but was not classically considered a contagious disease. In the present day, most sexually transmitted diseases are considered contagious, but only some of them are subject to medical isolation. Originally, the term referred to a "contagion" (a derivative of 'contact') or disease transmissible only by direct physical contact. In the modern day, the term has sometimes been broadened to encompass "any" communicable or infectious disease. Often the word can only be understood in context, where it is used to emphasise very infectious, easily transmitted, or especially severe communicable