To the diseases that cause the greatest harm to the development of the fetus, in the first place refers to rubella. Disease in the first months of pregnancy can cause severe malformations of the child (deafness, blindness, mental retardation, cardiovascular malformations). If rubella infection occurs before the 12th week, doctors recommend that you think about aborting your pregnancy.
If a woman suffered a rubella before pregnancy, then you can not be afraid - in the body there are antibodies, which provide immunity. Re-infection of rubella will not occur.
A dangerous damaging effect on the fetus is the cytomegalovirus. Infection with this virus in the early stages of pregnancy leads to the death of the embryo and spontaneous abortion. With continued pregnancy, cytomegalovirus causes abnormalities in fetal development. When a virus is infected in late pregnancy, children are born with symptoms of progressive jaundice, hemorrhagic diathesis, and impaired liver function.
But note: it's about infection during pregnancy. If you are already a carrier of this virus, in most cases with a good state of immunity they do not have a damaging effect on the unborn child. According to the antibodies to these viruses in the blood serum (igG, IgM) in what state is the immune system and whether it needs support from the outside. These viruses are often found when examining couples. Infection with viral hepatitis also poses a great danger for the child, because at all stages of pregnancy the disease can cause various fetal anomalies, and in the second half of pregnancy often leads to premature birth and stillbirth. Interruption of pregnancy with viral hepatitis in the early period is not shown.
Toxoplasmosis is another infection that can have an undesirable effect on the fetus. It is dangerous only for primary infection during pregnancy. Having determined the level of antibodies to toxoplasmosis (IgM, igG), you can judge whether this microbe has been seen on your way and for how long. If the future mother already has immunity, the infection is not dangerous. In the absence of it, care must be taken during cooking; It is not recommended to eat dishes from raw meat (there may be causative agents of toxoplasmosis); should avoid contact with unfamiliar animals (especially with cats, in whose feces are the causative agents of toxoplasmosis).