Luteal Phase Support for Frozen Embryo Transfers: Does Route of Progesterone Administration Make a Difference?

Progesterone is administered after embryo transfer for luteal phase support in order to create a favorable environment for implantation as well as decreasing uterine contractility. Progesterone can be administered either intramuscularly (IM) or vaginally. There are few studies that compare vaginal and intramuscular routes of progesterone administration for frozen embryo transfers (FET). Randomized control trials have been conducted to investigate mode of administration for progesterone in fresh IVF cycles and have concluded that there is no significant difference in clinic pregnancy rate with route of administration. The purpose of this study was to review all frozen embryo transfers performed at our institution and determine if there was a difference in clinical pregnancy rate with regard to route of progesterone administration. Patients that underwent FET cycles from January 1st 2008 until June 1st 2012 records were examined. Patients were excluded if they did not receive progesterone supplementation or if they received both IM and vaginal progesterone. Our progesterone supplementation protocols are IM (100mg progesterone in oil daily) and vaginal progesterone (Prometrium 200 mg bid orally for 2 days prior then 200 mg vaginal suppositories tid after transfer). We included FET cycles using donor oocytes (N=104). The primary outcome was clinical pregnancy rate (CPR) as defined by presence of fetal cardiac activity on ultrasound. Chi square and ANOVA were used where appropriate. Significance was p<0.05. The results are summarized in the table below. Three hundred and one patients underwent 504 FET cycles. There were 268 FET cycles that utilized IM progesterone support and 236 FET cycles that utilized vaginal progesterone support. There was no significant difference in the two groups with regard to patient baseline characteristics. The overall CPR was 34.13% per cycle with no difference in pregnancy rates in those that received IM versus vaginal progesterone.Table 1Patient Characteristics and Pregnancy Outcomes by Route of ProgesteroneIMVaginalp-ValueFemale age at embryo creation (Mean)31.5831.890.46FSH (Mean)7.557.760.38AFC (Mean)26.527.30.53BMI (Mean)25.9925.940.92Number of Embryos Transferred (Mean)2.172.120.46Clinical Pregnancy Rate % (N)35.45 (95)32.63 (77)0.51Biochemical Pregnancy Rate % (N)50.37 (135)43.64 (103)0.13Donor Oocyte Cycles CPR % (N)36.21 (21)26.09 (12)0.27Cycles with + hCG that went on to have a clinical pregnancy % (N)70.37 (95)74.76 (77)0.45 Open table in a new tab This study demonstrates that either vaginal or IM progesterone is effective for luteal phase support for frozen embryo transfers. Large multi-center randomized control trials need to be performed to confirm these findings.