Progesterone Levels During First Trimester

It’s normal to worry about all kinds of things when you’re pregnant. Your progesterone level is just one of them.

Some women worry their progesterone levels are too low. Some worry theirs are too high. Others worry their levels are fluctuating.

When it comes to progesterone levels, what’s normal?

And what about progesterone levels during first trimester of pregnancy?

Read on to find out more about progesterone and the role it plays in your body.

Progesterone levels during cycle

The first thing to know is that progesterone is a hormone.

It’s produced in the corpus luteum, a temporary part of your ovary. The corpus luteum is formed to hold the mature egg (ovum) that potentially becomes your baby.

Progesterone is known as the pregnancy hormone. It plays a crucial part in supporting a pregnancy.

This often makes women think higher or lower levels can affect their pregnancy. However, this isn’t necessarily the case.

Let’s look at how this hormone affects your body.

Progesterone levels after ovulation

Progesterone hormone levels begin to rise after a woman ovulates. After ovulation, she enters the luteal phase. This is the time between ovulation and the start of her period.

During the luteal phase, one of three things will happen:

• The woman doesn’t become pregnant
• The woman does become pregnant
• The woman becomes pregnant, but the pregnancy is not viable.

Hormone levels change, depending on which of these three things happens.

For example, if the fertilised ovum implants in the fallopian tube, an ectopic pregnancy occurs. This causes progesterone to rise. However progesterone production is low in ectopic pregnancy.

Luteal phase defect is another concern. This is when the corpus luteum doesn’t produce progesterone in high enough amounts for normal embryo growth and development. Low levels of progesterone mean the uterus isn’t prepared.

After ovulation, the level of progesterone rises, just in case the woman becomes pregnant. If a fertilised egg doesn’t implant in the wall of the uterus, the woman doesn’t become pregnant.

By about day 10 after ovulation, which is when progesterone levels peak, the body knows whether or not this has happened.

During the luteal phase, if no fertilised ovum implants, then progesterone begins to drop.

Before conception is confirmed, or the period starts, it’s difficult to tell which has happened, because pregnancy symptoms and PMS symptoms can be similar.

Progesterone levels during first trimester

If the woman isn’t pregnant, progesterone levels will drop and she’ll start her period.

If she has become pregnant, levels will continue to rise. The prime function of the corpus luteum is to produce progesterone until the placenta takes over. 

Normal levels of progesterone can vary, even within the same woman from day to day. This can cause many pregnant women to worry about their progesterone levels during first trimester.

Why do doctors prescribe progesterone in early pregnancy?

Generally, doctors don’t need to prescribe progesterone to pregnant women. Your body knows what to do, and your levels during pregnancy are probably fine.

If you’re concerned about your progesterone levels during first trimester, make sure to ask your doctor.

Therapy might be prescribed in these cases:

• Risk of miscarriage or history of spontaneous abortion
• History of low progesterone
• The baby was conceived by fertility treatments, such as IVF.

In the case of low progesterone, the hormone is given by the doctor, or the pregnant woman, via:

• Gel
• Pessary
• Injection.

If your doctor hasn’t mentioned low progesterone, your level is probably within the normal range.

There can be side effects, so it’s important progesterone is not prescribed without investigation.

What is a good level of progesterone in early pregnancy?

Dr. Andrew Orr is a reproductive medicine and women’s health specialist. He says:

“Progesterone levels are important in the early part of pregnancy, and they can fluctuate and vary for each woman and each particular pregnancy and circumstance”.

He goes on to outline the typical serum progesterone level during pregnancies:

• First trimester: 11.2 – 90 ng/mL
• Second trimester: 25.6 – 89.4 ng/mL
• Third trimester: 48.4 – 42.5 ng/mL

These numbers are important to see because they show the wide range possible.

In fact, it’s interesting to note that levels of progesterone in pregnancy can peak in the first trimester.

What is considered low progesterone in early pregnancy?

As Dr. Orr outlined, the typical range of progesterone levels during first trimester is 11.2 – 90 ng/mL.

By taking a quick look at the chart, you can see this is the time during pregnancy that has the widest possible range in progesterone levels.

You might have a lower number than other pregnant women you know, at the same week’s gestation. That doesn’t mean you need to worry about your number.

What level of progesterone indicates miscarriage?

Dr. Orr says, “Fluctuations are nothing to worry about, but if the levels bottom out, it can be a worry with maintaining a pregnancy”.

He stresses that human chorionic gonadotropin (hCG) levels should be measured alongside progesterone levels to assess the health of the pregnancy.

He stresses that it’s also important to monitor low progesterone where women have:

• High-risk pregnancies
• History of early pregnancy loss/miscarriage
• Fertility treatments, such as IVF.

Progesterone supplements can actually be a beneficial treatment during fertility treatments.

As Dr. Orr says, “Studies have shown that the rates [of successful pregnancies] are much higher, compared to cycles where no progesterone was used”.

Can a pregnancy survive with low progesterone?

Evidence suggests additional prescribed progesterone hormone can be useful in the cases of:

• Threatened miscarriage
• Recurrent miscarriage
• Preterm birth.

Dr. Orr stresses that “the need for progesterone supplementation will need to be evaluated case by case and individually”.

If you’re worried about your progesterone levels during first trimester, it’s okay to ask your doctor. However, the chances are that if you’re within the normal limits, everything is fine.

If they’re lower than normal, your doctor will talk to you about your options and possible outcomes.

Side effects of low progesterone include an irregular menstrual cycle and fertility problems.

What should progesterone levels be at 8 weeks?

As the chart shows, levels of progesterone fluctuate each week of pregnancy, depending on your baby’s gestational age.

A blood test will show what your serum progesterone levels are at different stages.

These levels are considered normal:

• First trimester: 11.2 – 90 ng/mL
• Second trimester: 25.6 – 89.4 ng/mL
• Third trimester: 48.4 – 42.5 ng/mL

Serum progesterone test ranges are quite wide but being on the low end of a range doesn’t mean your levels are too low.

Your age, the number of weeks of pregnancy you are, and the development of your baby also have an impact.

High progesterone levels in early pregnancy

Most women worry about low serum progesterone during pregnancy.

But what if yours is on the higher end?

Dr. Orr says there could be a few reasons for this:

• Pregnancy with multiples
• Ovarian cysts
• Molar pregnancy
• Ectopic pregnancy
• Ovarian cancer

As always, if you’re concerned about progesterone levels during first trimester, it’s best to get information about your health from your health practitioner.

A blood test and your serum progesterone levels can give your doctor the necessary information.

If you have low progesterone then a course of progesterone supplementation can be planned.