hibiscus tea

Abby • Mini toddler teacher, competitive figure skater, wife, dog mom
Hi ladies!
So my brother made me a cup of tea and said it was youthberry and orange blossom loose leaf tea by teavana. When I googled the tea I found out it has hibiscus in it which aparently you aren't suppose to have while pregnant because it can cause contractions that could lead to miscarriage. 
My question is has anyone else heard of this or drank hibiscus tea by accident? I had already drank over half the cup he made before I realized that it had hibiscus in it. Do you guys think it could cause early labor? I'm 37 weeks, but still worried that it could have negative effects on my baby. 
Thank you!!!