As folate is vital in the first trimester of pregnancy for healthy fetal development, the use of antifolates is strongly contraindicated in pregnancy and carries significant teratogenic risk. Low doses of methotrexate can deplete folate stores and cause side-effects that are similar to folate deficiency.
Cause of Adult Mumps. Adult mumps is caused by an infection with the mumps virus, which is found worldwide. The mumps virus is an RNA (ribonucleic acid) virus from the family Paramyxovirus of the genus Rubulavirus. The mumps virus only infects humans.
Why is mumps vaccine important? 1  Serious complications of mumps are more common among adults than children.  Rare complications caused by mumps include infections of the brain and spinal cord, arthritis, kidney and pancreas problems, deafness, and inflammation of the ovaries.