I volunteer (or used to) on camps with kids in foster care. One camp we had 20 kids attending and every single one of them had been removed from their parents care due to methamphetamine abuse. Some of them, but definitely not all, had some difficulties as a result of their parents drug use during pregnancy. Attention and mood regulation problems, problem solving skills. That kind of thing.
From speaking to their carers (the grandparents who also attended the camp) the main predictive factor of the children being impacted by the drug use during pregnancy was for how long, and how heavily. Some parents were sober during pregnancy and only started using drugs at a far later date due to unforeseen reasons. Some managed to stay sober during pregnancy and then fell off the wagon shortly after. Some didn't stay sober at all. Some used occasionally, others used heavily all the way through.
The children whose parents used very heavily all the way through their pregnancy were the most affected. Then the ones whose parents used occasionally. The kids whose parents used once or twice or not at all during pregnancy were non affected by the presence of the drug in their system, though they were hugely affected by the actions of their parents while using leading to their removal.
I think your baby will be fine, given that it's a one off use. Please don't torture yourself. Make sure you keep this one time to one time and don't allow yourself to shift the goalposts on this, or else you will indeed run the risk of harming your child.
And please, please once you give birth, live a life which puts your baby first. Make choices for that child. These kids who lost their parents, and having an ex friend raising two kids with a heavy meth using father - kids learn very quickly that their parents are choosing drugs over them. I heard kids say 'my mum loves meth more than she loves me' because they don't understand the nuance and complicated nature of addiction. They're too young to understand that their parents do love them, but they're struggling with something difficult to control. My ex friends step son once broke down in tears and had a massive meltdown because his dad went AWOL and missed his basketball game due to being on meth. Now he doesn't want to see his dad. He's only 10. Kids are like sponges. They absorb all this stuff and they can't give it all a proper meaning. So I urge you to do everything within your power to stay smart and use your recovery to your advantage to create a new drug free life for you and your child.
I can't judge a parent who uses, as I've only dodged that responsibility by avoiding having a child at all costs. But I've seen the damage done and I just hope people can know how these kids feel because they are so saddened by it.
) but yeah, there's no way we can answer that question unfortunately. Similarly there's no way anyone can tell if your coke usage has done any damage to your baby. There is a risk of heart defects, low birth weight, preterm birth, and possible other things, but if you only had a slip-up, and remain clean for the rest of your pregnancy, the risk should be low. 
