SIOUX CITY, Iowa (AP) — Nurse practitioners help fill the gaps left by a shortage of doctors in many places, and that is especially true in rural areas.

UnityPoint Health-St. Luke’s hospital has gone from having no nurse practitioners seven years ago to employing 20 today in a variety of fields.

Priscilla Stokes says nurse practitioners are with babies in the neonatal intensive care unit at St. Luke’s around the clock, so they can respond quicker than the on-call doctor.

Especially in rural areas, doctors are in short supply and that is expected to get worse as more older physicians retire.

Nurse practitioners can help because 20 states, including Iowa and Nebraska, allow them to practice without a doctor’s oversight if they have a master’s degree or better.