It is fishy for such high copay. Most insurance company covers 100% B超.
You need to check whether the doctor is in your insurance network. If so, call your insurance company and ask why you have to pay such high copay. If the insurance company can not solve the issue, ask you hu*****and to talk with the company human resource and let the human resource to handle it. Do not pay the doctor anything right now. Tell the doctor you are working with your insurance company to solve the problem.
If the doctor is not in your insurance network, you have to pay the doctor since you must have signed an agreement of responsibility on all the bills at the first visit. As I know, all doctors ask their patients to sign the agreement at the first visit. However, you still can file a complain to some place. I do not know much here. Hopefully, somebody else can help you if you can be more specific in questions in the future.
Finally, take good care of yourself and your baby. Money can not buy good health. Sometime you need to fight. Sometime you have to let it go.