As is the case with bacteria, the exact roles of different viruses in causing miscarriage is unknown. There are several difficulties in assessing the role of viruses. Firstly, it is difficult and complicated to isolate a virus from miscarried tissue. Also viral disease is common in and out of pregnancy—even the common cold has been implicated in sporadic miscarriages. Yet there are certain viruses that are known to be dangerous in pregnancy.

German measles (rubella)

This virus cross the placenta and infects both the placenta and fetal tissue, causing either congenital abnormalities or a spontaneous miscarriage. We do not know how often miscarriage miscarriages are caused by rubella, as most reports focus on the abnormalities found at the birth if the pregnancy continuing her pregnancy, as, in early pregnancy, there is an 85 percent chance that rubella could cause some major abnormality such as blindness, heart disease, or limb defects. While it is preventable by vaccination before you are pregnant, you can not be vaccination is weak it is nevertheless alive and could damage the fetus. You can have a blood test done before you get pregnant to see if you need to be immunized against the disease.

Genital herpes

This virus may cause a miscarriage if you have the initial attack in early pregnancy—during the first 20weeks. It is believed that the virus may cross the placenta and infect the embryo than recurring attacks, and it is accompanied by a high fever. It is not known for certain whether the fever or the herpes virus actually causes the miscarriage.

Remember, if you have already had an attack of herpes and become pregnanct, the recurring attacks are not believed to cause a miscarriage or any fetal abnormalities. So do not be concerned if you or your husband have a history of herpes. A recurring attack will only be significant in pregnancy if it causes a lesion, or ulcer, on the cervix, vagina or the labia, which is still present when you go into labor. In that case, you would require a delivery by C-section to avoid the baby’s coming into contract with the virus (in the ulcer). The drug effective against herpes, acyclovir, is not safe to use during pregnancy.

Other viruses

The AIDS ( aquired immunodeficiency syndrome) virus itself dose not cause a miscarriage but could be associated with general maternal illness, which may do it. Cytomegalovirus was once thought to be a cause of miscarriages, although no known link has yet been discovered. Mumps, measles, hepatitis A and B, and parvovirus may also have links with miscarriage. So yiu can gather the above, the extra role of some viruses in causing miscarriages is uncertain given our current knowledge.