The Importance of Progesterone Production During Early Pregnancy

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You can’t have a baby without it. The production of progesterone during pregnancy is essential! 

Your body naturally produces progesterone, and it has many health benefits. It supports bone, muscle, thyroid, and breast health, improves mood and sleep, boosts your energy, increases your sex drive, regulates immune function, and even protects against cancer. 

Progesterone is also necessary for a healthy menstrual cycle and reproductive system and essential to achieve and maintain a healthy pregnancy. Because of this, it should be of no surprise that “progesterone” literally means “pro-gestation”. 

As an essential hormone for fertility and reproduction, understanding how progesterone and pregnancy go hand-in-hand will help you make the best choices for your health with the guidance of your doctor. 

What exactly is progesterone?

Sex hormones impact sexual development and are essential for reproduction. Progesterone is one such sex hormone that your body needs to have a regular menstrual cycle each month and achieve pregnancy. 

The corpus luteum produces progesterone in your ovaries after ovulation. The corpus luteum is a structure that forms from the empty follicle that has released the egg. This structure releases progesterone during the second half of your menstrual cycle to support a possible pregnancy if conception occurs.

  • If fertilization does not take place after ovulation, the corpus luteum breaks down and stops producing progesterone. Low progesterone levels will then trigger menstruation.
  • If fertilization occurs, progesterone levels drastically rise. The placenta will take over progesterone production from your corpus luteum around the 7th to 9th week of pregnancy.

Progesterone is also produced in small amounts by your adrenal glands. And it might surprise you to know that even males produce small amounts of progesterone in their adrenal glands and testes.

Why does my body need progesterone for pregnancy?

Progesterone takes on several important roles before and during pregnancy. 

To prepare your uterus for a possible pregnancy, progesterone:

  • Makes your endometrium (lining of your uterus) thicker to nourish a developing embryo and fetus better.
  • Prevents the muscles in your uterus from contracting, which can prevent implantation.

During pregnancy, progesterone:

  • continues to maintain a nurturing environment for the developing fetus and helps the uterus grow.
  • continues to prevent contractions that can result in preterm labor.
  • inhibits ovulation so that a woman won’t become pregnant again
  • helps develop mammary glands to prepare the breasts for milk production.

How much progesterone is normal before pregnancy and during pregnancy?

The chart below shows the normal range of progesterone levels for an adult female before and during pregnancy. 

  • Before ovulation < 0.89 ng/mL
  • During ovulation ≤ 12 ng/mL
  • After ovulation 1.8 – 24 ng/mL
  • 1st trimester 11 – 44 ng/mL
  • 2nd trimester 25 – 83 ng/mL
  • 3rd trimester 58 – 214 ng/mL

Ranges vary depending on which lab checked your levels. Remember to talk to your doctor about your lab results.

Can progesterone levels go up and down during pregnancy?

Progesterone levels can fluctuate during early pregnancy. Each pregnancy is different, and levels can fluctuate more in some women than others. 

Don’t worry! As long as your levels stay within the normal range of hormone production, there should be no cause for alarm.

Does low progesterone cause infertility?

Although low levels of progesterone are not entirely to blame, research shows they can contribute to infertility.

Low progesterone levels can cause menstrual cycle irregularities and may prevent an embryo from implanting in the uterus. 

A rise in progesterone levels confirms ovulation. Low progesterone levels may mean that ovulation did not take place.

Keeping track of your hormone levels can tell you if you have ovulated each month. This is important data to share with your doctor if you are having a difficult time becoming pregnant.

Learn more :Low progesterone: All you need to know

Progesterone And Ovulation

The benefit of tracking your progesterone levels

The most common way to track your progesterone levels is through a blood test at a lab.

But you can also use technology like Inito to tell you when you ovulate by measuring the rise of progesterone metabolite-PdG levels in your body. Remember, a rise in progesterone levels is a confirmation that you have ovulated.

Currently, Inito is the only ovulation test that measures your FSH, estrogen, and LH levels to predict fertile days and progesterone metabolite-PdG levels to confirm ovulation on a single test strip. 

And unlike lab tests, technology like Inito allows you to measure your hormones at home, so you don’t have to make a trip to the doctor’s office.

Should I track my hormones in early pregnancy?

It is beneficial to track your hormone levels in early pregnancy.  

For a normal pregnancy in the first trimester, progesterone levels should value above 25 ng/mL about 98% of the time. Pregnancies with progesterone values below 5 ng/mL are usually considered nonviable. 

However, it’s important to talk to your doctor about your progesterone levels. Your progesterone levels could value below 25 ng/mL in your first trimester, but you may have a healthy pregnancy.

Benefits of progesterone treatments in early pregnancy

Miscarriages and preterm birth can be signs of low progesterone. To counteract this, doctors sometimes prescribe progesterone treatments.

The different types of progesterone treatments

Progesterone treatments can be in the form of creams and gels, suppositories, oral pills, and injections.

  • Creams and gels are applied to the skin or inserted into the vagina. These are used once a day until the 12th week of pregnancy.
  • Suppositories are administered vaginally up to 3 times a day. The vagina absorbs this treatment very well.
  • Oral pills are taken orally in the second trimester up until 37 weeks. 
  • Injections are shots of progesterone. Often women are taught to do these injections by themselves so they can be taken regularly.

Injections are the most commonly used progesterone treatment prescribed by doctors.

Who can use progesterone injections?

Progesterone injections contain 17 alpha-hydroxyprogesterone caproate, which is a synthetic form of progesterone. These injections are also known as 17P injections.

Generally, doctors prescribe this treatment when there is only one baby and not twins. The shots are administered weekly beginning in the second trimester up until week 37 or until delivery.

You may use progesterone injections to prevent miscarriage, pregnancy loss, and preterm birth if you:

  • have had recurrent miscarriages (3 or more)
  • have had a previous preterm birth
  • are using in vitro fertilization (IVF)
  • have taken mifepristone and want to reverse its effects

    Progesterone injections are not meant for you if you:
  • are carrying more than one baby
  • have a short cervix
  • have no prior preterm birth

If you take the 17P shots, common side effects may include itching, swelling, or soreness at the injection site. 

Side effects of progesterone treatments

In general, progesterone treatments in any form may have these common side effects:

  • breast tenderness
  • headaches
  • weight gain or weight loss,
  • acne
  • nausea
  • hair loss
  • excessive hair growth
  • drowsiness
  • dizziness

Tell your doctor if you experience any of the following:

  • vaginal bleeding 
  • breast lumps
  • swelling of the ankles or feet
  • mood changes (such as depression or anxiety)
  • dark patches on the skin
  • frequent or painful urination
  • dark urine
  • yellowing eyes or skin
  • abdominal pain
  • nausea or vomiting
  • headaches that don’t go away

If you experience any symptoms of an allergic reaction, such as a rash or trouble breathing, you should also notify your doctor right away.

Will Progesterone treatments affect my baby?

Great news! There’s currently no research showing a significant risk of adverse side effects for either you or your baby when using progesterone treatment.

The FDA has approved progesterone injections to reduce the risk of preterm birth. 

Also, we know it’s tough to hear, but using progesterone injections does not guarantee that you will not miscarry or carry your baby to term. 


Now that you know all about the importance of progesterone during pregnancy, you can decide the best way to track your hormone levels to confirm ovulation and a viable pregnancy. And if you believe you may need progesterone treatments, you can talk to your doctor about your options. 


  • Progesterone is a hormone that is necessary for a healthy pregnancy.
  • Progesterone prepares the lining of the uterus for implantation, supplies nutrients to an embryo and fetus so that it grows, and prevents the uterus from contracting in early pregnancy.
  • Progesterone levels can fluctuate in early pregnancy. However, they should stay in the same range.
  • It’s beneficial to follow progesterone levels before pregnancy to confirm ovulation and during early pregnancy to confirm a viable pregnancy.
  • If progesterone levels are low in early pregnancy, you can talk to your doctor about taking progesterone treatments.
  • You can take progesterone injections if you have had recurrent miscarriages in the past.

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