The National Hormone Laboratory at the Pope Paul, VI Institute for the Study of Human Reproduction in Omaha, Nebraska (popepaulvi.com) where Dr. Stroud, Dr. Stalling, and Dr. Grosvenor received their fertility certification has decades of data that depict women’s progesterone levels throughout the course of a normal pregnancy. By analyzing this data, we are able to understand the progesterone level in a healthy pregnancy at every point that pregnancy.  By contrast, we are also able to look at pregnancies with common complications and understand what the progesterone levels are in those pregnancies at various points along the developmental path.

As one might expect, in the abnormal pregnancies with complications such as preterm rupture of membranes, early miscarriage, preterm birth, and placental abruption, the progesterone levels are low at almost every point throughout the pregnancy.  The simple fact is, progesterone is critical to developing and maintaining a normal, healthy pregnancy.  Of course, it is not alone in this role, but it is nonetheless, a key component and without it, serious complications occur.  Most important, when we correct a low progesterone level; that is, when we bring the progesterone level up to the normal level, we dramatically reduce the number of complications.  This fact has been supported by numerous published research studies throughout the scientific literature in recent years.

How we go about supplementing progesterone varies. There are some who suggest taking oral progesterone. Others suggest taking vaginal suppositories, and still others suggest creams and/or injections. The Creighton Model FertilityCare™ protocol prescribes a dose and route of progesterone therapy based on the level of progesterone detected in blood tests. As the pregnancy progresses and (hopefully) the progesterone level rises, it is often possible to decrease the dose and frequency of the progesterone therapy and, in many cases stop supplementation altogether.

Why an injectable progesterone?

We’re often asked why we use injectable progesterone instead of oral forms of the hormone. Progesterone has what in pharmacology is known as a high “first pass effect.” That is, when taken orally, it enters the intestinal tract and then the bloodstream, and then goes to the liver—this is the normal pathway for most medications and nutrients. The vast majority of progesterone is metabolized by the liver as it passes through the first time from the intestinal tract and this is known as the “first pass effect.” As a result, there is very little of the progesterone left to exert its effect on the target organ (in this case, the uterus) once it passes through the liver.

By contrast when progesterone tablets are placed in the vagina, they are slowly absorbed through the walls of the vagina into the bloodstream and circulate in and around the blood vessels of the uterus before eventually making it to the liver. When progesterone is injected into the muscle in an oil base, it is even more slowly absorbed into the bloodstream, circulating around the body and exerting its effect before making it to the liver where it is metabolized.

So our strongest progesterone delivery tool is injectable; our next best tool is a vaginal tablet, and our least effective tool is the oral tablet.

We only prescribe what is known as, “Bio-identical” natural progesterone.  That is, the progesterone is in every way—biochemically, biologically, pharmacologically, and structurally—identical to the progesterone produced by the human body.  Some bottles of progesterone (Prometrium, for example) may have package inserts warning of the possibility of birth defects with the use of this medication.  This warning refers to artificial progesterone substitutes (typically called progestins, a common ingredient in oral contraceptives) and not the pure, bio-identical progesterone that we prescribe. The Pope Paul, VI Institute has decades of experience using bio-identical progesterone in pregnancy and has no reported problems resulting from its use.  We feel completely comfortable prescribing its use during pregnancy.