Turf Battles and the Public Health: An Analysis of Restrictive Scope of Practice Laws for Certified Nurse Midwives

Shortages of primary care providers have long been a concern in some parts of the country, but the insurance mandate in the Affordable Care Act and related Medicaid expansions have again put the issue on the forefront of health policy discussions.  One proposed solution to anticipated shortages is “fully enabled” scope of practice (SOP) laws that allow advanced practice registered nurses (APRNs) to practice to the full extent of their training, with little or no physician oversight.  The current regulatory environments for APRNs vary tremendously by state and range from supervisory relationships to complete independence.  Critics of fully enabled SOP contend that the quality of care suffers under a APRN’s direction, citing the shorter length of training and clinical experience required, while proponents argue that APRNs improve the efficiency of the system by providing care that is similar in quality to that of physicians while reducing costs substantially.

We examine this controversy in depth and evaluate the effects of different SOP restrictions on outcomes related to a specific group of APRNs—certified nurse midwives (CNMs).  CNMs are considered a viable substitute for obstetricians in cases of low-risk pregnancies.  However the extent to which CNMs may provide care may be limited by states’ SOP laws.  Although the current evidence supports the use of CNMs, as the health outcomes of patients treated by CNMs is show to be equivalent or superior to those of patients treated by physicians, this research is generally conducted without regard to the practice environment, and as a result, states that alter SOP laws are doing so in the absence of rigorous national studies on the direct effects of these laws.  At issue is whether the laws serve to protect the public health or merely impose barriers to practice.

In this paper, we examine the effects of variations in state SOP laws for CNMs on: 1) prenatal care and pregnancy related health behaviors; 2) outcomes related to labor and delivery; 3) infant health outcomes; 4) the labor market for CNMs; and 5) the substitution between physician and CNM services.  We estimate reduced form equations that link the laws directly to the health outcomes and to the intermediary mechanisms.  Our data come from a variety of sources with the pregnancy and birth outcomes taken from birth certificate records. 

Preliminary results show that individuals in states that allow CNMs to practice independently and to the full extent of their training have some improved outcomes including lower probabilities of C-sections and higher birth weights.  There are no noticeable differences among the different practice environments in terms of early prenatal care receipt and gestation length.  We also show no evidence that fully enabled laws affect the supply of CNMs or the substitution from MDs to CNMs.  These results point to the conclusion that fully enabled SOP for CNMs may not alleviate shortages, but will also not harm mothers and children, and can provide benefits in terms of health outcomes and reduced health care costs.