Environmental factors and some chemicals may result in malfunctioning in fetus during pregnancy. The impact of teratogens on pregnancy differs depending on agent’s characteristic, duration and dose of exposure, and the stage of pregnancy at exposure.

Effects of teratogens can be observed within two weeks on the embryo in all or none form. Embryo will either be aborted or can survive and develop into a healthy baby. Effects of teratogens can be observed especially between 3-10 weeks during which organogenesis takes place. Later than this period, it is hardly possible for the fetus to be affected.

In case of any teratogenic exposure doubt of women during their pregnancy, all the information must be obtained very carefully, then family should be consulted about it.