There are more than 600 different chemical used in the process of drilling for oil and gas using the facking method. Many of these chemicals are known cancer causing agents. Many of these chemicals also carry warnings to avoid contact by children and pregnant women. So it's reasonable to assume these chemicals would cause birth defects in the unborn.
Fracking is a seemingly new way to get fossil fuels out of the ground that has been becoming more popular but has met a lot of problems in the last year or more. Fracking has showed to cause earthquakes but apparently its also caused problems with water contamination. I believe it is best to assume that it could cause birth defects rather than assume it does not.
No, well water contaminated by fracking does not cause birth defects if it is consumed by livestock or residents, because the dangers caused by fracking are complete hype. There are environmentalists who had to go to great lengths to make the water near fracking appear dangerous. It is not really a significant problem.
Fracking has not become a common practice in the United States until recently. There is not enough evidence at this point to suggest that the practice can contaminate water and eventually lead to birth defects and cancer. At this point, it would be too extreme to be so cautious about something that we barely have evidence for.
There is no real evidence that fracking is detrimental to the health of the population and the livestock surrounding it. Fracking is very safe and many studies by large organizations have shown that the negative effects are limited. The alternative to fracking is coal - something far worse for the environment.