Progesterone is often referred to as “the pregnancy hormone,” and for good reason. Without it, women would be unable to carry a pregnancy to term.
In fact, women wouldn’t be able to get pregnant at all. This essential hormone is produced by the ovaries, and it helps your uterus prepare for pregnancy.
Here are six facts about progesterone levels in pregnancy that every woman should know.
1. Progesterone Affects Your Body in Numerous Ways
Progesterone affects your body and your pregnancy in many ways. It:
- Helps regulate your menstrual cycle.
- Prepares your body for pregnancy.
- Thickens the lining of your uterus to support a healthy pregnancy.
- Prevents uterine contractions, which can lead to a miscarriage.
- Raises your body temperature between ovulation and menstruation.
- Thickens the uterus, and creates a mucous plug to keep the uterus free of bacteria.
- Increases glycogen and arterial blood in the lining of the uterus to provide the fetus with vital nutrients.
2. Progesterone Levels Change During a Pregnancy
Progesterone levels in early pregnancy are different than levels seen during the final stages of pregnancy.
Weeks 1 & 2
During the first few weeks of pregnancy, your progesterone levels will be roughly 1-1.5ng/ml. Keep in mind that the gestational age of your baby is calculated from the start of your last menstrual period – even though you weren’t pregnant at this time.
At this time, the body is still preparing for a pregnancy and will produce progesterone as a result.
Weeks 3 & 4
Weeks three and four will occur after ovulation. This is when the ovaries will start producing higher levels of progesterone.
During this time, your progesterone levels will rise to about 2ng/ml. The production of progesterone will thicken the lining of your uterus and prepare it for implantation.
During week 3, fertilization occurs, and progesterone levels will rise by 1 to 3ng/ml every day or every other day until it peaks at 10-29ng/ml.
Weeks 5 & 6
By the 6th week, progesterone levels should remain at 10-29ng/ml. Doctors want levels to be above 6-10ng/ml during this time.
At this level, the progesterone will stimulate uterine blood vessel growth, which will help build and maintain a healthy placenta. The growth of blood vessels doesn’t just occur in the uterus, but all over the body.
This is what gives women that characteristic pregnancy glow.
Weeks 7 to 14
Between weeks 7 and 14, the placenta begins producing progesterone, and gives the ovaries a break. The placenta will continue producing progesterone for the remainder of the pregnancy.
This is when levels peak or start to decline. After week 10, levels begin increasing again to reach a peak of 15-60ng/ml just before the third trimester.
From here on out, levels will continue to increase. If you’re pregnant with multiples, expect levels to be even higher.
For a quick breakdown:
- First trimester: 9-47ng/ml
- Second trimester: 17-147ng/ml
- Third trimester: 50-200ng/ml
3. Low Progesterone during Pregnancy Can Lead to a Miscarriage
Low progesterone levels can cause complications during a pregnancy. In the early stages, it can be a sign of an ectopic pregnancy, or an indication that there is a great risk of miscarriage.
If progesterone levels are below 6ng/ml during the 6th gestational week, the pregnancy is usually not viable. Without sufficient progesterone levels, the body will be unable to carry the baby to term.
4. Suppositories Can Help Correct Low Progesterone Levels
During your pregnancy, your doctor will test your progesterone levels to assess your risk of a miscarriage. If you have lower than normal progesterone levels, you may be given progesterone suppositories that will help increase your levels to support a healthy pregnancy.
Not all women find success with this method, but many do. Suppositories will keep your levels high enough until the placenta begins producing the hormone on its own.
5. The Cause of Low Progesterone is Not Well Understood
Low levels of progesterone are caused by both known and unknown factors. Hormones are complex and still not well understood.
Some women may have no issues getting pregnant, but the placenta is unable to produce the appropriate amount of progesterone for some reason. Doctors believe that low progesterone may be caused by:
- Poor nutrition
- Stress
- Lack of exercise
In some cases, certain medications can also interfere with your body’s ability to produce progesterone.
6. It’s Possible to Birth a Healthy Child despite Low Progesterone Levels
Low progesterone levels does not always mean that your pregnancy will end in miscarriage. When suppositories are taken, it is possible to sustain a pregnancy and carry a baby to term.
Your doctor will monitor your condition closely to ensure that the pregnancy is healthy and moving along as normal. Many woman have given birth to healthy babies despite starting their pregnancy with low progesterone levels.
Suppositories and close monitoring can mean a successful and happy pregnancy.