Mikveh after birth of a girl

A woman may immerse in the mikveh as soon as fourteen days have passed, as stipulated in the Torah (VaYikra 12:5, "If she gives birth to a female, she shall be temeiah for two weeks similar to her status during niddah").  In theory, a hefsek taharah may be made as early as the fifth day (where the day of childbirth is day one), followed by seven clean days and waiting an extra two nights before immersion.  In practice, however, it is very rare for postpartum bleeding to stop soon enough for immersion to be possible after two weeks, and a woman typically makes a hefsek taharah when bleeding stops, with no unique delay after giving birth to a girl.  

Some communities developed the custom of delaying immersion after having a girl until the end of eighty days (the time the Torah establishes as dam tohar, a distinct law that has lost is practical significance).  Many halachic authorities have condemned any such stringency, and today it is not practiced.