Does Low Progesterone Affect Your Ability to Get and Stay Pregnant? (2024)

Progesterone is an important hormone that helps maintain a healthy pregnancy. There is much debate about how — or whether — low levels of progesterone can affect a pregnancy. Here’s what you need to know about this controversial topic.

What is progesterone?

Progesterone is one of the all-important hormones needed to sustain a healthy pregnancy— and its name says it all: pro-gestation. The hormone is made at first by the ovarian corpus luteum — the follicle that was emptied when the egg was released during ovulation.Progesterone works to mature the uterine lining, readying the uterus for a potential pregnancy.

Once conception occurs, thepregnancy hormone human chorionic gonadotropin (hCG) signals the corpus luteum to continue producing progesterone until around the second month of pregnancy, when the placenta takes over the responsibility of secreting progesterone. Progesterone keeps the uterine lining healthy and thick, ensuring the right environment for the developing fetus.

What does it mean if you have low progesterone levels?

A normal level of progesterone is needed for a pregnancy to progress normally, and as time goes on, those levels will increase. What’s considered normal when it comes to progesterone levels? Here’s the range:

• First trimester: 11.2 to 90 nanograms per milliliter (ng/ml)
• Second trimester: 25.6 to 89.4 ng/ml
• Third trimester: 48 to over 300 ng/ml

A level that falls significantly below normal (below 5 ng/ml in the first few weeks of pregnancy, for instance) is considered low progesterone, but luckily, most women have normal levels of progesterone, and low progesterone during pregnancy is quite uncommon. In fact, it’s unlikely you’ll even get tested for progesterone levels unless your practitioner is concerned about something and feels it’s important to know.

Low progesterone causes

Low progesterone during early pregnancy is often the result of one of the following:

• Anectopic pregnancy
• A miscarriage
• A threatened miscarriage (when there is vagin*l bleeding, spotting and/or cramping in the first trimester)

Low progesterone symptoms

Low progesterone symptoms may include the following:

• Spotting or bleeding
• Cramping

How can low progesterone affect pregnancy?

There’s plenty of debate surrounding the question of whether low progesterone affects pregnancy. Some experts believe that progesterone deficiency is a real issue, and an equal number of experts say that low progesterone doesn’t have any impact at all on pregnancy.

Those who believe that low progesterone can affect pregnancy say that low levels can lead to an inadequately prepared uterus, and that the lack of a thick endometrial lining in the uterus can make it difficult foran embryo to implant or for a pregnancy to sustain itself.

Does low progesterone increase your chance of having a miscarriage?

Again, it’s very unclear. While it’s true thatwomen who have experienced a miscarriage tend to have lower levels of progesterone, it’s uncertain if the low progesterone level caused the miscarriage or if the miscarriage caused the low progesterone level.

Adding to the confusion is the research, including a recent randomized study — and the largest study to date — showing that giving supplemental progesterone to women with threatened miscarriages does not reduce the rate of miscarriage or increase the chances of a continued pregnancy.

In other words, this study didn't support the theory that low progesterone increases the risk of miscarriage.

Low progesterone treatments

If your doctor still feels that low progesterone may be contributing to your miscarriages, she may decide to try supplemental progesterone. Progesterone can be given in the following forms:

• Progesterone injections
• vagin*l progesterone suppositories
• Progesterone oral tablets

In the case of recurrent miscarriages, you would take it before conception and continue to take it through the early stages of pregnancy to help sustain the pregnancy and avoid miscarriage.

Do keep in mind, though, that the evidence finds no positive effect of such treatment. The one exception: women who have had at least three prior miscarriages. Research does show that they may benefit from progesterone therapy.

Does low progesterone contribute to fertility issues?

Most experts agree that low progesterone (or aluteal phase deficiency — when the luteal phase of the menstrual cycle is too short and therefore progesterone levels remain too low) has little clinical significance, and that itdoesn’t contribute toinfertility.

In fact, the medical consensus is that a luteal phase deficiency doesn’t exist on its own, but is rather a by-product of another underlying hormonal issues (thyroid dysfunction, for instance), and that once the other hormonal issue is treated, normal luteal function (and therefore normal progesterone levels) are restored.

Can low progesterone affect IVF?

AnIVF cycle(where hormones are carefully activated and deactivated) differs from a natural cycle (where the ovary produces progesterone until the placenta takes over) because some of the fertility medications needed (GnRH agonist and antagonists in particular) prevent the ovary from making progesterone.

That means women undergoing an IVF pregnancy will have induced low progesterone and therefore will need supplementary progesterone to make up the shortfall.

In the case of an IVF pregnancy, progesterone — taken as an intramuscular injection or via the vagin* as a gel or suppository — will likely be prescribed to support the developing pregnancy during the first two to three months.

Do progesterone supplements help prevent preterm birth?

If you’ve delivered prematurely in a previous pregnancy and are now carrying only one baby (not multiples), your doctor may talk to you about supplemental progesterone. Some studies have shown that getting weekly shots of progesterone starting at around 16 to 20 weeks of pregnancy and continuing through week 36 reduces the risk of preterm birth, although a more recent study did not show any benefits.

Both the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine say that all expecting women with previous preterm births should discuss with their doctors if progesterone supplementation is right for them.

If you don't have a history of preterm birth and your doctor notes thatyour cervix has shortened below 2 centimeters when you're 16 to 24 weeks pregnant (which may increase the odds of a preterm birth), your practitioner may prescribe a daily progesterone gel — it comes in a tampon-like applicator that you place in your vagin* — or vagin*l progesterone suppositories until 37 weeks of pregnancy.

Progesterone supplementation in these situations has been shown to effectively reduce the risk of preterm birth.

Should you use OTC progesterone suppositories or progesterone cream for low progesterone levels?

Using over-the-counter progesterone creams is not recommended at all. Not only are such creams not regulated by the Food and Drug Administration (FDA), which means there are no set standards for their formulation and concentration levels, but also there’s no research that shows any benefit.

What’s more, some types of progesterone cream do not create a significant increase in progesterone levels, so even if progesterone were beneficial during pregnancy, a cream wouldn’t be the right source anyway.

Only take a progesterone suppository if your doctor has recommended it for you.

Are there any side effects with progesterone cream, progesterone suppositories or progesterone supplements?

There may be no side effects — or there may be a number of side effects. A lot depends on the type of supplement you’re taking.

For instance, progesterone suppositories can be messy and sometimes result in these side effects:

• vagin*l irritation
• Itching
• Burning
• Yeast infections
• Cramping
• Increased vagin*l discharge

Progesterone shots can cause side effects such as:

• Pain
• Swelling and bruising at the injection site
• Headaches or migraines
• Breast tenderness
• Drowsiness
• Dizziness
• Fluid retention
• Bloating
• Hot flashes
• Constipation
• Weight gain

There is no consensus on whether low progesterone is truly an issue facing some moms-to-be. Most of the research tends to conclude that progesterone supplementation does not decrease the risk of miscarriage.

The research conclusively shows that progesterone supplementation doesn’t help with fertility, but it does help to decrease the risk of a preterm birth in women with a history of preterm labor as well as those who have a shortened cervix but no history of preterm delivery. Bottom line: Follow what your doctor recommends, but don’t worry if you’ve been told your progesterone is low.