Does meaning change if I use "by a taxi" instead?
Native speaker’s answer
Rebecca
No, the overall meaning does not really change here if you used "by a taxi" instead. The only difference here is that "by a taxi" emphasizes that the taxi is the reason that the baby was delivered. "In a taxi" has a less strong emphasis on the role of the taxi in delivering the baby, and instead emphasizes the position of the baby, who was inside the taxi.