To the best of our knowledge, this
segulah is fairly flexible.
A woman should not immerse while she is in
niddah, though if she is immersing as usual following her time in
niddah, she can also arrange to have her immersion be after a woman in her ninth month.
There is nothing barring a woman from immersing when she is already
tehorah. If she is already
tehorah, the
segulah immersion need not involve all of the usual
preparations, and she should not recite a
bracha over the immersion.
It is best to consult a
mikveh attendant in advance to make these arrangements.
This response was updated on 8 April, 2021.