natural family planning

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Timing sexual intercourse to avoid the time of ovulation (if pregnancy is not wanted) or to fall within that time (if pregnancy is desired).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of several methods of family planning that do not involve sterilization or contraceptive devices or drugs; coitus is avoided during the fertile time of a woman's menstrual cycle