allergic reaction to that arm; small knot around the injection site and that this morning it was a little worse; it is pink and the size of a base ball; that it is pink and the size of a base ball. She states that it is "warm to the touch and swollen but not hard but she has got some swelling there; warm to the touch; swollen but not hard but she has got some swelling there; a pregnant patient received a Tdap vaccine (it was confirmed to be Adacel); Initial information received on 17-Nov-2021 regarding an unsolicited valid non-serious case from a other health professional via the Agency (under the reference 00862766).   This case involves a 34 year-old female patient who experienced allergic reaction to that arm (hypersensitivity), small knot around the injection site and that this morning it was a little worse (vaccination site nodule), it is pink and the size of a base ball (vaccination site erythema), warm to the touch (vaccination site warmth), swollen but not hard but she has got some swelling there (vaccination site swelling) and (vaccination site inflammation) after receiving vaccine DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE [ADACEL] (exposure during pregnancy).  Data regarding this pregnancy were received prospective.  The date of last menstrual period was not reported.  The estimated due date was not reported.  The patient past medical history, medical treatment, vaccination and family history were not provided.  The patient had unknown previous pregnancy.  On 15-Nov-2021, the patient received a 0.5 ml dose of suspect DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE (lot U7055BA and expiry date: 03-Jun-2023) (Frequency once) via intramuscular route in the right deltoid for prophylactic vaccination.  On an unknown date, the patient developed a non-serious allergic reaction to that arm (hypersensitivity), small knot around the injection site and that this morning it was a little worse (vaccination site nodule), pink and the size of a base ball (vaccination site erythema), warm to the touch (vaccination site warmth) and swollen but not hard but she has got some swelling there (vaccination site swelling) (vaccination site inflammation) (unknown latency) following the administration of DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE.  It was also the case of vaccine exposure during pregnancy (latency same day).  It was reported "The nurse states that on Monday a pregnant patient received a Tdap vaccine (it was confirmed to be Adacel) and the patient came back to the office today with an "allergic reaction to that arm". The nurse would like to know if she can provide the AE information verbally or if she has to fill out a form. The patient was coming back today for another unrelated appointment. The nurse states that it is pink and the size of a base ball. She states that it is "warm to the touch and swollen but not hard but she has got some swelling there".  Details of laboratory data not reported.  The patient was treated with BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE] and advised ice and either Benadryl cream or capsules.  At time of reporting, the outcome of the event was unknown for all events.  Additionally, at time of reporting, the outcome of the pregnancy is unknown.   There will be no information available on the batch number for this case.