A trial in 2000 suggested that remaining supine for 10 minutes after intrauterine insemination could increase pregnancy rates, but that study was small and unbalanced, lead author Inge M. Custers and colleagues note.
To verify the benefits of supine immobilization, Custers, from the Academic Medical Centre, Amsterdam, The Netherlands, and co-researchers compared pregnancy rates in 199 women who were randomized to 15 minutes of supine immobilization and 192 who were assigned to an immediate mobilization group. Intrauterine insemination was being performed for unexplained, cervical factor, or male subfertility.
The immobilization group had an ongoing pregnancy rate per couple of 27%, significantly higher than the18% rate seen in the control group (RR 1.5). The corresponding live birth rates were 27% and 17% (RR 1.6).
The ongoing pregnancy rates in the immobilization group for the first, second, and third treatment cycles were 10%, 10%, and 7%, respectively, compared with corresponding rates of 7%, 5%, and 5% in the control group.
In an accompanying editorial, Dr. William L. Ledger, from the University of Sheffield, UK, notes that while a 15-minute immobilization period may improve pregnancy rates, it may present logistical issues for a busy assisted reproduction center. “The results,” he adds, “suggest that units should carry out their own evaluation of immobilization versus immediate mobilization after intrauterine insemination, to test the hypothesis in the ‘real world.’”