Miscarriages are sadly one of the most common experiences in a woman’s reproductive life. About twenty percent of all pregnancies end with a mother losing her baby to miscarriage, most often in the first trimester. Some women will tragically experience the same devastating loss over and over again, without doctors being able to provide much of an explanation. Now, new studies have revealed that supplementing with one simple hormone could offer moms and babies a better chance: Progesterone.
According to the Independent, the research was a team effort between scholars from the University of Birmingham and Tommy’s National Centre for Miscarriage Research in the United Kingdom. One study, known as the PROMISE trial, was published in the American Journal of Obstetrics and Gynecology and looked at more than 800 women in the U.K. and the Netherlands who had experienced repeated miscarriages. Researchers observed that patients who received micronized vaginal progesterone supplementation had a 3 percent higher live-birth rate.
A second study, known as the PRISM trial, was published in BJOG: An International Journal of Obstetrics and Gynecology and evaluated 4,153 women being treated at U.K. hospitals. All of the patients had early pregnancy bleeding, a scary symptom that can sometimes presage a miscarriage. Results revealed that for moms who had already suffered at least one prior loss, progesterone supplementation led to 5 percent more babies born alive. Women who received a placebo didn’t show the same benefit.
In the most desperate cases, for women who had at least three prior miscarriages, micronized vaginal progesterone was found to boost the live birth rate by an amazing fifteen percent.
How Progesterone May Reduce Miscarriages
Given that about 1 million miscarriages occur in the United States alone every year, these studies suggest tens of thousands of pregnancies could possibly be saved.
The Independent quotes senior researcher Dr. Adam Devall, “The role of first trimester progesterone supplementation in the treatment of pregnancies at high risk of miscarriage is a long-standing research question that has been debated in medical literature for over 60 years.” But this isn’t news to Fertility Awareness practitioners and NaProTechnology-trained physicians. For decades, they’ve known that progesterone hormones can be key to helping prevent miscarriage.
How? “In pregnancy, progesterone will maintain the uterine lining, provide endometrial nutrition for the fetus, and will prevent premature uterine contractions,” Allison Jung, a physician’s assistant specializing in OB-GYN medicine, wrote for Natural Womanhood earlier this year. If a pregnant mom’s body doesn’t naturally make enough progesterone to keep her uterus a safe, healthy environment for her growing baby, she could experience a “chemical pregnancy,” a common term for a very early miscarriage.
Although a test at her doctor’s office may reveal low levels of pregnancy hormones in her blood stream, and an at-home urine test may show a faint positive, a woman who suffers this form of miscarriage will begin bleeding at around 5 weeks gestation, days before the pregnancy can be seen on ultrasound. Some women who aren’t tracking their cycles may interpret the bleeding as simply a “late period” and not realize what has happened. “A woman may experience miscarriage later in the first trimester if she has low progesterone and the endometrial secretions are weak, thus starving the fetus before the placenta can take over,” Jung writes.
Low progesterone can affect gestational health in the late stages of pregnancy, too. Since the hormone helps the uterus grow and keeps it from contracting, progesterone supplementation is a very important way to protect moms and babies from the dangers of premature birth during the late second and early third trimesters.
How can a woman know whether she has low progesterone? She doesn’t have to wait to get pregnant to find out. By pro-actively charting her menstrual cycle with a Fertility Awareness-Based Method (FABM), a woman and her healthcare team can detect potential problems, including progesterone deficiency. For instance, her charts may reveal an abnormally-short luteal phase. The luteal phase is the part of a woman’s cycle that begins after ovulation and lasts until her period begins. If charts show fewer than 10 days between ovulation and menstrual bleeding, and especially if this is coupled with tale-end brown bleeding at the end of menstruation, this suggests that a progesterone deficiency may be the culprit.
How do NaPro doctors address progesterone deficiency?
Unlike mainstream OB/GYNs, NaPro doctors don’t use birth-control pills, which flood the body with a constant dose of a synthetic, factory-made version of progesterone every day. In a healthy woman, progesterone is highest after ovulation, so that’s when NaPro doctors supplement with bio-identical progesterone and personalize the dose for the individual woman, using the patient’s charts as a guide to determine when the medication should be administered. Some women take progesterone as an oral pill or vaginally as a suppository, while others take it as “progesterone in oil” intramuscular injections.
What about after conception? “If a woman is pregnant, her NaPro doctor will evaluate her natural progesterone production every two weeks throughout her entire pregnancy. Replacement will depend on her lab levels and how far along she is in the pregnancy; progesterone should only be replaced to physiological levels,” Jung writes. The emphasis is on restoring the body to as close to a natural healthy performance as possible.
Which route of progesterone administration is most effective?
NaPro’s protocol for progesterone support during pregnancy recommends intramuscular progesterone. According to anecdotal evidence, women who are unable to tolerate this route are alternatively offered vaginal progesterone. But NaPro’s stats on the effectiveness of one route over the other are hard to come by.
We do have some recent data from research intro progesterone supplementation to decrease miscarriage rates in women who have undergone assisted reproductive technology (ART) procedures like in vitro fertilization (IVF), to which NaPro, NEO Fertility, FEMM, and other forms of restorative reproductive medicine are a natural alternative. While the PRISM and PROMISE trials mentioned above did not study the effectiveness of intramuscular progesterone, a 2019 study of women who received oocyte donations (a form of ART) and had weekly intramuscular progesterone injections starting just after embryo transfer had significantly lower rates (16.7%) of miscarriage than women who received vaginal progesterone 47%).
On the other hand, this 2020 research found that live birth rates were equivocal (one route was not superior to the other) for intramuscular vs. vaginal progesterone gel given to women who underwent frozen-embryo transfer for IVF. Additionally, 2014 research found that vaginal progesterone had greater impact on endometrial tissue (recall that the endometrium is the inner lining of the uterus) and decreased systemic effects, which should lead to fewer side effects.
The bottom line
The U.K.’s National Institute for Health and Care Excellence says it is updating its treatment guidelines on managing potential miscarriage, taking into account the new evidence about the efficacy of progesterone in preventing miscarriage. The new research is once again backing up the value of using FABM and NaPro principles in women’s health. That is great, exciting news for moms and their babies!
This article was updated on April 4th, 2023 to resolve a broken link from the Independent and to add research regarding the effectiveness of intramuscular vs. vaginal progesterone.