Tetanus And Diphther. Tox (PF) Syringe precautions What should I know regarding pregnancy, nursing and administering Tetanus And Diphther. Tox (PF) Syringe to children or the elderly?If you are: Pregnant: Only When Necessary: Nursing: Precaution: NO EVIDENCE/REPORTS OF ADVERSE EFFECTS ON NURSING INFANT. Giving tetanus and diphther. tox (PF) Syringe to a child under 12: management or monitoring precaution: Not recommended in pediatrics age < 7 years.