What we have learned about best practices for recruitment and retention in multicenter pregnancy studies.

For 30 years, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network has had significant impact on clinical practice in obstetrics. The MFMU Network has conducted 50 randomized clinical trials and observational studies designed to improve pregnancy outcomes for mothers and children. Each center has a designated clinical research nurse coordinator who coordinates the day-to-day operations of each trial and leads a research team that is responsible for recruitment and retention of participants. Some of the lessons learned by the nurse coordinators over the past 30 years are described with examples from recent studies. Best practices that we have amassed from our experience are also described.