Is Vaginal or Intramuscular Progesterone Better For Pregnancy Success?

When a patient or couple begins an IVF cycle, we are always hopeful that success will be achieved in the very first cycle. Despite excellent pregnancy rates, some patients may require more than one cycle to achieve a healthy pregnancy. Most failed cycles occur because the embryo was genetically abnormal and not healthy enough to develop into a baby. Sometimes other factors play a role, too. For instance, if the uterine lining is not optimized, then it may be more difficult for an embryo to implant. Progesterone is often prescribed to support implantation. Patients often ask is vaginal or intramuscular progesterone better for pregnancy success?

Progesterone Supplementation During IVF

Progesterone support is a standard component of most fresh and frozen IVF cycles. Progesterone is administered through either vaginal or intramuscular routes, most commonly. The vaginal route is messy at times, but otherwise well-tolerated. The intramuscular approach is historically very effective, but is associated with more discomfort and localized skin reactions.

Is Vaginal or Intramuscular Progesterone Better For Pregnancy Success?

A recent study compared live birth rates from over 1,000 frozen embryo transfer (FET) cycles with three different approaches to progesterone support: vaginal progesterone, intramuscular progesterone, or a hybrid combination of the two (daily vaginal progesterone with intramuscular progesterone every third day). These investigators found that live birth rates were significantly lower in the vaginal progesterone group (27%) compared to either of the other two groups. Additionally, 50% of pregnancies in the vaginal progesterone group ended in miscarriage. Pregnancy rates were strong (and similar) in the intramuscular progesterone group (44%) and the hybrid group (46%).

This study demonstrates that vaginal progesterone alone does not provide adequate progesterone support for FET cycles. We recommend intramuscular progesterone or a hybrid approach.

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We are very proud of our pregnancy rates at Fertility Centers of New England. If you have more questions, like is vaginal or intramuscular progesterone better for pregnancy success or what the best treatment path for you is, please contact us for an initial consultation. We are here to help.