Tea is rich in theanine, folic acid, DHA, AA, polyphenols and polysaccharides, which is actually beneficial to the development of multiple births.

But nothing can be overdone. Tea also contains caffeine, which will stimulate the nerves. Too much intake is not appropriate.

So pregnant women can drink black tea, but it must be moderate. It is generally believed that the daily drinking amount should be controlled within 15g.

But what you said about vanilla black tea may not be appropriate. This kind of black tea is made of black tea with vanilla essence. The essence composition is not very clear. I suggest you take a conservative attitude.