Progesterone is an important hormone for the establishment and maintenance of pregnancy.  Because of this important role, progesterone deficiency has been studied since the 1950s as a possible cause of some miscarriages.  Many of the early studies done on progesterone were small and poor quality, making it difficult for doctors to make evidence-based recommendations for its use.   However, more recently there have been two large, high-quality placebo controlled trials (the PROMISE trial and PRISM trial) that have shown encouraging results. 

As a naturopathic doctor, I use progesterone often in my practice to prevent pregnancy losses.  Half of all miscarriages are thought to be due to chromosomal errors, leaving half of all losses being chromosomally normal.  These are the cases where finding the root cause of the problem becomes especially important.  In my experience, I find progesterone most helpful for treating three types of patients: 

  1. Women with a history of 1 or more miscarriage.  The PROMISE trial found that the benefit from using progesterone increased with the number of previous miscarriages a woman has had, with the greatest benefit being women with 3 or more.   
  2. Women with bleeding in pregnancy or “threatened miscarriage”.  This is especially true for women who have had multiple miscarriages and current pregnancy bleeding.  The PRISM trial found the live birth rate in this group was 72% in the progesterone group vs 57% in the placebo group.  
  3. Women with a luteal phase defect.   Luteal phase defect is a condition where a women’s ovaries do not make enough progesterone in the second half of her menstrual cycle.  This becomes problematic in early pregnancy, because the progesterone needed for early pregnancy comes from the ovary for the first 7-9 weeks before the placenta takes over.  

Progesterone is typically prescribed in a bioidentical vaginal tablet form that is taken daily throughout the first trimester.  It has a very good safety record which was demonstrated by the PROMISE and PRISM trials.  Neither found any evidence of an increase in congenital abnormalities or short-term harm  

There are ways to prevent miscarriage so please talk to your healthcare provider if you think progesterone might benefit you.  Our qualified naturopathic doctors at Mint Integrative Health are here to help.   Because one loss is one too many. 

Dr. Alana Shaw ND