Mercury is good at cleaving off segments of chromosomes so that they do not contain the appropriate number of genes. If a break occurs at the planning and initial growth stage of pregnancy, then several things can happen. If chromosomal damage is in critical areas like the heart or brain, this usually produces a spontaneous abortion, or the mother's body will reabsorb the fetus. Non-critical defects, like alteration in the number of fingers, toes, etc, may be allowed to survive, but problems in the heart liver, kidney or brain will probably be aborted. Another problem that is frequently overlooked is that a baby can not only be exposed to mercury from its mother during pregnancy, but if breast fed, the baby can still receive a source of mercury that can alter its growth and development patterns.
Mercury can be a pregnancy problem even prior to conception.
Mercury has been found in the ovaries and testes of people who have been exposed to mercury. One researcher suggests that mercury in the ovaries could be responsible for the lack of implantation of fertilized eggs. He also states that mercury in the testes could be an adequate source of genetic disturbance to produce birth defects. One researcher, Kuntz, identified that the number of dental fillings in the mother correlated with the amount of mercury in her blood. Since Chang has pointed out that the fetus is eight times more sensitive to mercury than its mother prior to pregnancy , people would be well-advised to know that a reduction in the number of fillings in both parents prior to conception could result in less exposure to their new baby.