You know if you leave it too late to fly back and the baby is born here, you will probably have to pay the NHS fees, if you have a caesarian the cost of that could be a lot of money.
Remember on your visit visa application form, the questions about medical treatment, if you've not paid that could have a negative effect on getting a future visa until the money is paid..
If you wanted the baby born here you should have applied for the correct visa, either a medical visit visa or a fiancée visa.
If the father is British the child will be British, you should google 'Zambrano' and best interests of the children, thou I'm not sure you qualify
But get professional advice![]()