Are The Syncope Episodes Related To Menstruation Cycle?

My 12 year old daughter ( 5'5", 150 pounds) had two episodes of fainting this weekend. This has NEVER happened before and we have no family history of syncopy. Took her to ER. Blood sugar, blood pressure- normal. Slight jump in HR (20 beats) when checked sitting to standing. Rec'd IV fluids due to dehydration. She is due to start her period in 3 days. Is syncopy related to the menstrual cycle at all?