To Nofia,

To Ortodox Jew, family planning and menstruation come under the broader
category of what is called Family Purity Laws. They are quite complex. In a
nut shell, a women is considered to be ritually unclean, and unable to have
sexual relations with her husband, after menstruating or giving birth until
after waiting a pre-set period of time and then  immersing herself in a
ritual bath called a Mikva. If she is not having periods because of
breastfeeding, then she would not technically need to return to the mikva.
However, she would probably consult with her Rabbi before following anyone's
advice. Is she trying to prevent or encourage another pregnancy? If your
community has an orthodox synagogue, you might want to call their rabbi for
additional information, or see if your community has a Mikva and call them.

Good Luck!

Debbie Rabin, OTR, CLC