Good Evening, I hope you are doing well. You have selected an interesting career. Way to go. I think it is absolutely great that you have a desire to ask questions about becoming an OB-GYN or a neonatologist. Here is my response to your question: The requirement for entering the field is that you must obtain a four year degree either in pre-med, biology; and chemistry prior to applying for medical school. You can refer to the 1) Occupational Outlook Handbook; 2) http://doctorly.org/how-to-become-a-neonatologist/; 3) https://work.chron.com/educational-steps-becoming-neonatologist-5120.html; and 4).career trend.com for further information about becoming an OB-GYN or neonatologist.
I hope this answers your question. Good luck to you. You are on your way to great success. If you need further assistance, I will be happy to help you. Enjoy!