Association for Public Policy Analysis & Management

As a result of population growth, aging of the population, and implementation of the Affordable Care Act (ACA), it is estimated that there will be a shortfall of 35,000-52,000 adult primary care physicians by 2025.   One solution to the anticipated shortage is expanding scope of practice (SOP) for advanced practice nurses (APRNs), which may help by allowing APRNs to practice to the full extent of their training, and to diagnose and treat with only limited or no physician oversight.  Critics contend that quality of care may suffer under a nurse’s direction, however, while proponents argue that APRNs improve efficiency of the system by providing care that is similar in quality to that of physicians while reducing costs substantially.

We evaluate the effects of expanded SOP laws on health outcomes and related mechanisms for a specific group of APRNs—certified nurse midwives (CNMs).  Shortages of obstetricians are a concern nationwide and especially in rural areas.  CNMs have the potential to alleviate this shortage, however the extent to which CNMs may provide care is often limited or restricted by states’ SOP laws.  We examine different aspects of SOP laws for certified nurse midwives and evaluate the effects of the laws on 1) prenatal care and pregnancy related health behaviors; 2) outcomes related to labor and delivery; 3) birth outcomes; 4) the labor market for CNMs; and 5) the substitution between physician and CNM services.  We focus on SOP laws that pertain to physician oversight requirements and prescribing rules, and examine the effects of SOP laws in geographic areas with and without evidence of strained primary care provider capacity.  We use the ‘natural experiment’ of states’ changes in laws affecting the SOP for certified nurse midwives over the 1994-2012 time period to estimate reduced form equations that link the laws directly to the health outcomes and to intermediary mechanisms.  Our data come from a variety of sources with the pregnancy and birth related outcomes taken from the birth certificate records provided by the National Vital Statistics System. 

The results show that states which allow CNMs to practice independently and to the full extent of their training have improved maternal and child outcomes including lower probabilities of C-sections and elective C-sections, a lower probability of smoking during pregnancy, and higher birth weights.  There are also no noticeable differences among the different practice environments of early prenatal care receipt and gestation length.  We also show evidence that broad laws increase the supply of CNMs, but do not appear to affect the substitution from MDs to CNMs.  These results point to the conclusions that unrestrictive scope of practice laws for CNMs will not harm mothers nor children, and can provide substantial benefits in terms of health outcomes and potential health care costs.