If a pregnant lady takes tablet to get periods will it affect the baby

what type of tablets is this you are writing about?

Sounds like some form of progesterone pills ie provera if so then no it will not do any harm however if she is ttc and no period and if not preggo then she will need to seek help from a Re to help her become preggo. However like always she needs to first check to see if she is preggo via hpt and beta hcg and if preggo then no period will come and no need to take the pills. If she isn't ovulating then she cannot become preggo and needs help from a dr to aid in this process:)))