[Intramuscular vs vaginal progesterone for luteal support in cycles of in vitro fertilization]

To determine the effectiveness of two routes of progesterone supplementation by intramuscular vs. vaginal administration, for luteal phase support of patients undergoing in vitro fertilization (IVF) procedures.

Rush Presbyterian St' Lukes Medical Center and Rush Northshore Medical Center in Chicago, Illinois.

A total of 79 consecutive patients undergoing IVF procedures between August 1997 and July 1998 were assessed; 42 women received progesterone in oil intramuscularly (i.m.)--50-100 mg daily and in 37 patients progesterone was applied as intravaginal gel (80 mg daily), according to patient's preference.

A chart review of the patients' data was performed. There were no statistical differences between the two groups of patients with respect to age, total number of ampoules of gonadotropins used during stimulation, number of oocytes retrieved and fertilized or number of embryos transferred. We then compared pregnancy rates per cycle and pregnancy rates per embryo transferred and miscarriage rates between two groups. Statistical analysis was performed using Student's t test.

There were no statistically significant differences between two groups. The pregnancy rate per cycle for i.m. progesterone group was 33% and for vaginal gel group--25% (p = 0.42). Pregnancy rates per embryo transferred were also similar (8% for i.m. group and 5% for vaginal gel group (p = 0.42). Miscarriage rates were also within the same range: 0.083 for vaginal gel and 12% for i.m. group, (p = 0.48).

The route of post-transfer progesterone administration does not appear to affect the pregnancy rate in IVF cycles. Therefore the least expensive and the most convenient route of progesterone administration could be utilized.