I see that religious Jews have large families. Is it true that they don’t practice birth control?
The Aish Rabbi Replies
Generally speaking, the use of contraceptives is forbidden in Judaism. The basic idea is that the one who does the family planning is God.
However, there are circumstances when birth control is not only permitted, but advisable. To determine the practical application, a competent rabbinic authority must be consulted to clarify:
1) Does this particular case justify using birth control?
2) What kind of birth control should be used?
3) For how long should it be used?
If you need, I can recommend a rabbi to speak with in your city.
For more background on this issue, I suggest reading "Birth Control in Jewish Law" by David M. Feldman (published by Aronson Inc.).