According to "Mayo Clinic guide to a healthy pregnancy" (2004), page 156,
"Will my pubic hair be shaved?
Not likely. Shaving a pregnant women's pubic hair also used to be standard
practice, to prepare a clean site for delivery. Now it's known that hair
doesn't contribute to infection, so shaving is rarely, if ever,done."
I think it applies to vaginal birth. C-section is probably different.