A large majority of surveyed family planning specialists have stopped routine Rh testing and Rh immunoglobulin use before 12 weeks of pregnancy, aligning with 2022 recommendations and reshaping how early pregnancy care relates to hemolytic disease of the fetus and newborn (HDFN), according to a study presented recently at the SMFM 2026 Pregnancy Meeting in Las Vegas, NV, February 8 to 13, 2026.
This study, led by researchers at Westchester Medical Center, examined how US Complex Family Planning providers responded to updated guidance suggesting that routine Rh testing and Rh immunoglobulin, often called RhIg, may not be necessary for abortion or miscarriage before 12 weeks.
Rh incompatibility can, in some cases, lead to HDFN in a future pregnancy. However, experts have questioned whether very early pregnancy events carry enough risk to justify routine testing and preventive treatment.
Researchers emailed 575 providers through a professional listserv and received 241 responses, a 41.9% response rate. Among respondents, 152, or 63.1%, reported initiating Rh testing only after 12 weeks. An even larger group, 179 providers, or 74.3%, said they administered RhIg only after 12 weeks.
Read more about testing and diagnosis for HDFN
“The two most influential factors were the practice region and the practice setting, perhaps most likely driven by state policies as described in the qualitative analysis of the study, in addition to expertise driven by maternal-fetal medicine specialists at those respective sites,” explained this study’s authors.
U.S. providers in the Midwest were 1.81 times more likely than those in the Northeast to follow updated guidance. Those in the West were 2.25 times more likely. Clinicians practicing at Planned Parenthood or independent clinics were also more likely to adopt the changes than those at academic medical centers, with a relative risk of 1.39.
Most respondents, 161 of 203 who answered that question, or 79.3%, described a deliberate effort to revise practice at their facility. Some, 78 of 203, or 38.4%, reported disagreements among clinicians during the transition. Still, patients rarely objected. Two-thirds said patients rarely disagreed, and 17.2% said patients never disagreed.
For patients, the shift may mean fewer blood tests, fewer injections and potentially lower costs during early pregnancy care. Experts stress that the change applies only to care before 12 weeks and does not eliminate Rh testing or RhIg when clinically indicated later in pregnancy. These results suggest that early pregnancy care is evolving based on emerging evidence and regional policy differences, while continuing to protect against HDFN when the risk is considered meaningful.
Sign up here to get the latest news, perspectives, and information about HDFN sent directly to your inbox. Registration is free and only takes a minute.
