Brief Answer:
Stop using the drug immediately.

Detailed Answer:
Hi,
Welcome to Healthcare Magic.
I am Dr Ramadevi Wani. I will be answering your concerns today.

I am sure you are aware that Meth is not good for you or your baby. Meth is a stimulant which crosses the placenta. It compromises placental blood supply and affects nutrition of your baby.
It's continued use results in birth of small babies. It can cause preterm delivery and placental abruption ( separation of placenta from uterine wall).
The children born to mothers using meth later show delay in physical growth and academic delay. However its use in early pregnancy is unlikely to increase the frequency of congenital anamolies.

Stop using this drug immediately. I appreciate that it is easy to say, but difficult to stop. But where there is a will there is a way. Discuss with your doctor who will guide you to join rehabilitation programme.

I hope this helps.
If you have further concerns, I will be happy to answer.

---