 [ Symptoms ] we had our son 22 days ago 9 days after delivery we started having sex again could i become pregnant  our ob said that we needed to start using birth control after 40 days but the web has conflicting advice i am breastfeeding him [ Disease ] i would definitely speak to your pediatrician and pediatric dentist for specific advice on what and how much fluoride supplement to use it is suggested that only children living in non fluoridated areas use dietary fluoride supplements between the ages of 6 months to 16 years your physician or dentist can prescribe the correct dosage for your child based on the previously mentioned factors