Pregnant and kink...

So I couldn’t think of anything else to label this post and am not sure where else to post it...but I have a question. My SO and I recently tried fisting and he couldn’t get his whole fist in me due to my hips being narrow. Well now I’m pregnant and he said I may need a c-section due to my hips. So here’s my question: how far do the hips widen during pregnancy if at all? If he couldn’t even get his fist in there is it still possible for them to widen enough to let a baby pass through? I really don’t want a c-section if I don’t have too...