Headache; This spontaneous retrospective pregnancy case was reported by a consumer and describes the occurrence of HEADACHE (Headache) in a 27-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 008C21A) for COVID-19 vaccination.     The patient's past medical history included Venous malformation NOS (this is a congenital condition) on 13-Jan-1994, Alcohol use (1 drink to 4 drinks once every 4 months.) on 13-Jan-2015, Cannabis use (2 pot brownies and never more) on 16-Jun-2019, Maternal exposure during pregnancy, Iron deficiency (Due to Venous Malformation) on 19-Mar-2019 and Surgery (Surgery done on Hemangioma on scapula) in March 2019. Concurrent medical conditions included Obsessive-compulsive disorder (I may need to increase my Zoloft Rx to manage my worsening anxiety.) since 01-Jun-2000, Anaemic since 21-Mar-2021, Hemangioma, Sulfonamide allergy (Allergy to sulfa.) and Drug allergy (Allergy to ciproflaxin). Concomitant products included IRON (SPATONE IRON SUPPLEMENT) from 05-May-2021 to an unknown date for Anemia, SERTRALINE HCL from 13-Jun-2010 to an unknown date for Obsessive-compulsive disorder.    On 03-May-2021 at 6:00 AM, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. The patient's last menstrual period was on 09-Sep-2020 and the estimated date of delivery was 12-Jun-2021. On an unknown date, the patient experienced HEADACHE (Headache). The patient received mRNA-1273 (Moderna COVID-19 Vaccine) beginning around the  thirty-third week of the pregnancy. The vaginal delivery occurred on 07-Jun-2021, which was reported as Full-term. For neonate 1, the birth weight was 3458 grams (7lbs 10oz) with an APGAR score of 9 and 10 at (1, 5 minutes). The outcome was reported as Delivered NOS. Baby delivered on 39 weeks and 2 days. Infant length 48.26cm. Course of pregnancy and delivery was smooth, no complications. The patient was treated with PARACETAMOL (TYLENOL [PARACETAMOL]) for Headache, at an unspecified dose and frequency. At the time of the report, HEADACHE (Headache) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 19-Oct-2020, Glycosylated haemoglobin: 117 mg/dl (High) 117 mg/dl (but it corrected itself). On 13-Jan-2021, Ultrasound scan: single viable intrauterine gestation (abnormal) single viable intrauterine gestation. On 12-Mar-2021, Glucose tolerance test: 96 mg/dl (normal) 96 mg/dl. On 02-Oct-2021, Pregnancy test: positive (Positive) Positive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Received the Moderna Vaccine for primary series whilst pregnant; delivered and was breastfeeding when booster shot was received.  This spontaneous case concerns a 27-year-old female patient with a relevant medical history of Maternal exposure during pregnancy, who experienced the expected non serious event of Headache after mRNA- 1273 Moderna vaccine. The patient received the second dose of the vaccine at 33 weeks of gestation. The delivery occurred at approximately 38 weeks of gestation, which was reported as normal pregnancy outcome. The event Headache occurred after the second dose of mRNA- 1273 Moderna vaccine at an unknown date. It had occurred after the first dose too, however, rechallenge is not applicable, since medical treatment was given for its resolution. The benefit-risk relationship of mRNA- 1273 vaccine Moderna Vaccine is not affected by this report. Maternal exposure during pregnancy was captured in the associated first dose case, thus it was not captured again in this case.   This case was linked to MOD-2021-393494 (Parent-Child Link). This case was linked to MOD-2021-384883, MOD-2021-384808 (Patient Link).   See case MOD-2021-393494 for details regarding the child case.  Most recent FOLLOW-UP information incorporated above includes: On 22-Nov-2021: Significant Follow up received on 22-Nov-2021 contains Pregnancy Outcome form and Concomitant medication, medical history added.; Sender's Comments: This spontaneous case concerns a 27-year-old female patient with a relevant medical history of Maternal exposure during pregnancy, who experienced the expected non serious event of Headache after mRNA- 1273 Moderna vaccine. The patient received the second dose of the vaccine at 33 weeks of gestation. The delivery occurred at approximately 38 weeks of gestation, which was reported as normal pregnancy outcome. The event Headache occurred after the second dose of mRNA- 1273 Moderna vaccine at an unknown date. It had occurred after the first dose too, however, rechallenge is not applicable, since medical treatment was given for its resolution. The benefit-risk relationship of mRNA- 1273 vaccine Moderna Vaccine is not affected by this report. Maternal exposure during pregnancy was captured in the associated first dose case, thus it was not captured again in this case.