Hi & Welcome. I can understand your concern. Since your period has already begun while nursing your baby you need to have an emergency postcoital contraception in the form of Positnor tablet because of the broken condom during sexual act. Since Positnor tablet contains ONLY Levonorgestrel (Progestin), it is an effective and safe contraceptive of choice during lactation (nursing mother). Postinor does not adversely affect the composition of milk, the growth and development of the infant or the milk supply. Although some amount of the drug may be passed on through your breast milk, but your child is not likely to experience any adverse effects from. Kindly remember that Positnor tablet will be 90% effective in preventing pregnancy if taken within 72 hours following unprotected sex due to broken condom. Also, the tablet should not be used more than once in a month and should not be continued to use as a regular birth control measure. Hope I could answer your query. Take care. A feed back is appreciated.