Immobilization May Improve Pregnancy Rate After Intrauterine Insemination

Laurie Barclay, MD

October 30, 2009

October 30, 2009 — Immobilization in the supine position for 15 minutes after intrauterine insemination may improve ongoing pregnancy rates, according to the results of a randomized controlled trial reported online October 29 in the British Medical Journal.

"Intrauterine insemination with or without ovarian hyperstimulation is probably the most frequently applied fertility treatment in the world," write Inge M, Custers, PhD, from the Academic Medical Centre in Amsterdam, the Netherlands, and colleagues. "One of the questions that has remained unresolved is whether pregnancy rates are positively influenced by immobilisation after insemination."

The goal of this study was to compare the efficacy of intrauterine insemination in achieving ongoing pregnancy in women who had 15 minutes of immobilization vs immediate mobilization after the procedure.

At 1 academic teaching hospital and 6 nonacademic teaching hospitals, 391 women undergoing intrauterine insemination for unexplained, cervical factor, or male subfertility were randomly assigned to 15 minutes of immobilization in the supine position (n = 199) or immediate mobilization after insemination (control; n = 192).

Compared with the control group, the immobilization group had a significantly higher ongoing pregnancy rate (27% [n = 54] vs 18% [n = 34]; relative risk [RR], 1.5; 95% confidence interval [CI], 1.1 – 2.2; crude difference in ongoing pregnancy rates, 9.4%; 95% CI, 1.2% – 17%).

Live birth rates were 27% (n = 53) in the immobilization group compared with 17% (n = 32) in the control group (RR, 1.6; 95% CI, 1.1 – 2.4; crude difference for live birth rates, 10%; 95% CI, 1.8% – 18%). In the first, second, and third treatment cycles, ongoing pregnancy rates in the immobilization group were 10%, 10%, and 7%, respectively, vs 7%, 5%, and 5%, respectively, in the mobilization group.

"In treatment with intrauterine insemination, 15 minutes' immobilisation after insemination is an effective modification," the study authors write." Immobilisation for 15 minutes should be offered to all women treated with intrauterine insemination.... Although immobilisation takes more time and occupies more space in busy rooms, the intervention will be economic in the long run, as pregnant patients will not return in subsequent cycles."

Limitations of this study include relatively small sample size and small differences in treatment protocols among participating centers, such as inseminated volume of semen and type of hyperstimulation.

"In intrauterine insemination, spermatozoa are inseminated in a small volume of fluid directly into the uterus," the study authors explain. "As a consequence, immediate mobilization might cause leakage of this volume together with spermatozoa out of the uterus; alternatively, movement of processed sperm to and up the fallopian tubes may take longer than after intercourse."

In an accompanying editorial, William L. Ledger, from the University of Sheffield, United Kingdom, notes that overall pregnancy rates in this study were lower than in many centers that do not use immobilization, and that the use of ovarian stimulation varied considerably between centers.

"The results suggest that units should carry out their own evaluation of immobilisation versus immediate mobilisation after intrauterine insemination, to test the hypothesis in the 'real world,' " Dr. Ledger writes. "If successful, more couples could be spared the rigorous and costly process of in vitro fertilisation. Future trials should assess the effect of different durations of immobilisation."

The authors and Dr. Ledger have disclosed no relevant financial relationships.

BMJ. Published online October 29, 2009.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.