Advanced maternal age: Usually defined as age 35 or more for the mother at the time of delivery of her baby.
Advanced maternal age predisposes to Down syndrome (trisomy 21). The risk of having a Down syndrome baby rises with maternal age. It essentially doubles from 1 in 725 at maternal age 32 to 1 in 365 at maternal age 35. And the risk continues to climb with the years and is 1 in 32 at maternal age 45.
- Advanced paternal age
Advanced paternal age: A man who is age 40 years or older at the time of conception. (There is no universally accepted definition of advanced paternal age but this criterion is often used in genetic counseling.) Advanced paternal age is associated with an increased risk of new mutations in the offspring. This risk for genetic […]
Adventitia: The outermost connective tissue covering of any organ, vessel, or other structure. For example, the connective tissue that surrounds an artery is called the adventitia because it is considered extraneous to the artery. “Adventitia” comes from the Latin “adventicius” meaning “foreign, strange, extraneous, coming from abroad or from outside.” Other English words that stem […]
Adventitious: Coming from an external source or occurring in an unusual place or manner. Not inherent, inherited or innate but rather occurring accidentally or spontaneously. When a doctor or nurse auscults (listens to) the chest or abdomen, adventitious sounds are those that are normally not heard coming from the chest or abdomen. The word “adventitious” […]
- Adverse effect
Adverse effect: A harmful or abnormal result. An adverse effect may be caused by administration of a medication or by exposure to a chemical and be indicated by an untoward result such as by illness or death.
- Adverse event
Adverse event: In pharmacology, any unexpected or dangerous reaction to a drug or vaccine.