To chart postpartum, we suggest using the Lactational Amenorrhea Method while you are in the first few months of post-partum. It is a modified version of the Sympto-Thermal Method, and does not require taking your temperature. A couple of resources you might want to check out that discuss natural birth control while breastfeeding are: Taking Charge of Your Fertility by Toni Weschler and Breastfeeding and Natural Child Spacing by Sheila Kippley.