Progesterone During Pregnancy: Uses & Treatments

One of the many hormones critical to a successful pregnancy is progesterone. And while some pregnancies produce this hormone at the right levels, other pregnancies may require an extra boost of progesterone in the form of a shot or suppository. 

In this article, we’ll take a look at what exactly progesterone is, what it does during pregnancy, and when your doctor may prescribe progesterone. We’ll also cover all the side effects, risks, and benefits of taking progesterone to support your pregnancy. 

Even though progesterone can be found in both the male and female body, this article will focus on the role that progesterone plays in menstruation and pregnancy specifically.

What is progesterone?

In women, progesterone is a type of steroid hormone critical for menstruation, conception, and pregnancy. 

Before pregnancy, the role of progesterone is to keep the menstrual cycle regulated and prepare the uterine lining to accept a fertilized egg. During pregnancy, progesterone helps to protect the fetus and prepare the body for birth. 

Please note that Progesterone (measured in ng/mL) should not be confused with PdG (measured in ug/mL) the urine metabolite of progesterone commonly used in at-home testing. Mira tracks PdG. All the information provided in this article about Progesterone is purely educational. Please always refer to your healthcare provider.

Progesterone and pregnancy

Before pregnancy

In women of reproductive age, progesterone is produced by the corpus luteum during the second half of the menstrual cycle. It is also produced by the adrenal glands, which are located on top of the kidneys. 

Prior to ovulation, progesterone levels are typically less than or equal to 0.89 ng/mL. During ovulation however, progesterone levels can rise to 12 ng/mL. After ovulation and prior to menstruation (i.e. the luteal phase), progesterone can range anywhere between 1.8-24 ng/mL. 

During this time, the primary role of progesterone is to help the body maintain a regular menstrual cycle, prepare the uterine lining for fertilization, and facilitate a successful fertilization process. 

During pregnancy

During pregnancy, the corpus luteum continues to produce progesterone until around week ten. Then, it is produced by the placenta throughout the remainder of the pregnancy. 

Progesterone levels gradually rise throughout pregnancy, ranging from 11-44 ng/mL, 25-83 ng/mL, and 58-215 ng/mL during the first, second, and third trimesters, respectively. 

The core functions of progesterone during pregnancy are to maintain the uterine lining, prevent ovulation, and aid in the development of the cervical mucus plug. However, it also helps to prepare the breasts for breastfeeding, while also strengthening the pelvic wall muscles for delivery. 

After pregnancy

After pregnancy, progesterone levels fall back to their pre-pregnancy levels (0.89 ng/mL during the follicular phase and up to 12 ng/mL during the luteal phase). However, this process does not happen overnight, and it can take up to three weeks or longer for hormones to resume their normal patterns. 

 

Progesterone treatment during pregnancy

Why would you need progesterone treatment?

A doctor may recommend progesterone treatment in any of the following cases:

• Your progesterone levels are lower than average
• You have a short cervix
• You are experiencing recurrent miscarriages

The most common treatment options are vaginal progesterone suppositories or a progesterone shot – here’s a brief look at both options and who they are suitable for. 

Vaginal progesterone

Vaginal progesterone is a vaginal suppository consisting of anywhere between 50-400 mg of progesterone. Once inserted, progesterone is slowly released and then absorbed into the body where it can help to support and maintain your pregnancy. 

Who should consider this

If you are pregnant and have a cervix that is less than 2.5 centimeters (25 millimeters) long, vaginal progesterone suppositories may help to reduce your risk of premature birth. In fact, one recent study found that among pregnancies with a short cervix, vaginal progesterone helped to reduce preterm births by approximately 42%. 

It’s important to note that vaginal progesterone is more effective in singleton pregnancies, with one study finding vaginal progesterone to have a limited effect on twin pregnancies. 

When to take vaginal progesterone

Vaginal progesterone should be prescribed and taken under the guidance of your doctor. If you are concerned about your progesterone levels and the health of your pregnancy, speak with your doctor and they can provide you with the correct progesterone treatment plan for your situation. 

Progesterone shots

In addition to progesterone suppositories, it is also possible to receive progesterone shots that contain a type of synthetic progesterone called 17 alpha-hydroxyprogesterone caproate. Progesterone shots are typically given on a weekly basis during weeks 16-37 of pregnancy. 

Who should consider this

Progesterone shots are typically recommended in cases where there has been a spontaneous premature birth with just one baby in the past. Progesterone shots should also only be administered in patients without liver disease, untreatable high blood pressure, or certain cancers that are sensitive to hormones. 

When to get progesterone shots

Progesterone shots should be prescribed and administered under the guidance of your doctor. If you are concerned about your progesterone levels and the health of your pregnancy, speak with your doctor and they can provide you with the correct progesterone treatment plan for your situation.

Side effects of taking progesterone during pregnancy

In general, progesterone treatments may cause any of the following side effects:

• Drowsiness
• Fluid retention
• Hot flashes
• Vaginal discharge

Those taking vaginal suppositories may also experience any of the following:

• Vaginal irritation, itching, and burning
• Vaginal dryness
• Yeast infection
• Headaches, nausea, vomiting, or diarrhea

Benefits of progesterone

Progesterone helps to prevent preterm births in women with either a short cervix or in those who have experienced recurrent miscarriages. 

Recent suggests that vaginal progesterone may help to:

• Improve the live birth rate in women with recurrent miscarriages by up to 15%
• Decrease the chances of preterm birth by 35% in women with a previous preterm delivery.
• Reduce preterm births by up to 42% in women with a short cervix.

Risks of progesterone 

Like other medicines and supplements, progesterone also comes with a few risks. The most common negative side effects of progesterone include headache, changes in heart rate, fatigue, and low blood pressure. In rare cases, it may cause dizziness, drowsiness, and an upset stomach. Long term, progesterone may increase your risk of certain conditions such as breast cancer, ovarian cancer, and endometriosis. 

FAQs about progesterone and pregnancy

Please note that urine PdG should only be used for confirming ovulation. Mira Confirm Wands are not designed nor approved or cleared for monitoring early pregnancy status, miscarriage, fetal health tracking, or other diagnostic uses for which progesterone might be an indicator.