Can low progesterone cause miscarriage?

**Trigger Warning: This blog discusses miscarriage and pregnancy loss.**

Low progesterone is a hormonal imbalance that can make it more difficult to conceive. It can cause a lot of unwanted symptoms such as mood swings, premenstrual syndrome (PMS), spotting before your period, or menstrual cramps.

You may be wondering, "can hormonal imbalance cause miscarriage?" Unfortunately, low progesterone also may be a cause of early miscarriage. Keep reading to learn more.

Why is progesterone important?

Progesterone is one of the two main sex female hormones, whose role is to regulate the cycle, prepare the body for conception, and maintain pregnancy. Progesterone rises immediately after ovulation by the corpus luteum (empty follicle) and should stay elevated at optimal levels throughout the luteal phase, from about days 7-10 past peak fertility (also known as the implantation window).

During this time, its main job is to stabilize the uterine lining and make it “sticky” enough in order for implantation to occur. It also provides nutrients to the endometrial (uterine) lining and prepares a welcoming uterine environment in which the embryo can thrive.

During the first trimester of pregnancy, the corpus luteum maintains the production of progesterone. The corpus luteum is a temporary endocrine structure that is the remains of the ovarian follicle which released the egg during ovulation. The corpus luteum continues producing progesterone until about week 8 of pregnancy.

Between weeks 7 and 10, the placenta takes over the progesterone production. Until the end of the pregnancy, the placenta will continue producing progesterone — while providing nutrients and oxygen to the growing baby — to control the growth and development of the fetus.

What causes low progesterone?

Low progesterone may be caused by various issues, including:

Polycystic Ovarian Syndrome (PCOS): PCOS is by far the most common cause of anovulation. PCOS is a common conditions where an excess amount of androgens (male sex hormones) causes a hormonal imbalance that can inhibit ovulation. If ovulation does not occur, then there is no empty follicle to produce progesterone.

Thyroid issues: Issues with your thyroid may impact progesterone levels, directly by impairing its production or indirectly by raising Prolactin levels, which can inhibit the production of other hormones.

High cortisol: Cortisol is known as the “stress hormone” because it is produced when our body needs to respond to stress. When we are under constant stress, our body needs more cortisol. In order to produce more cortisol, our body will “steal” other, less vital, hormones like progesterone in order to keep up. In severe cases, elevated cortisol may even cause anovulation or amenorrhea.

Unhealthy body weight: Being over or underweight can inhibit progesterone production. Fat cells produce estrogen and excess fat cells can lead to estrogen dominance. On the other hand, lack of fat cells can cause our body to think we’re in a famine. In this case, our body will take nutrients and resources from our reproductive system in order to help us survive.

What causes miscarriage?

First trimester miscarriages are unfortunately a common occurrence and are always devastating. If you have experienced a miscarriage, we are so sorry for your loss.

It is hard to estimate how many miscarriages occur in early pregnancy since many of them happen before a woman even realizes she was pregnant. The best estimate is that 1 in 4 pregnancies ends in miscarriage, and over 80% of these losses occur during the first trimester.

There are many causes for miscarriage, including:

• Chromosomal abnormalities: Chromosomal abnormalities are the most common cause of miscarriage. Scientists still don’t totally understand why chromosomal abnormalities lead to miscarriage.
• Uterine abnormalities: Uterine abnormalities like arcuate, septate, or bicornuate uterus may make implantation more difficult and impact fetus development in the case that pregnancy does occur. However, corrective surgery can help improve pregnancy outcomes.
• Thyroid issues: Thyroid disease may impact your hormones, including progesterone, and therefore may cause early (and even recurrent) miscarriage. Women with hypothyroidism (underactive thyroid gland) present an increased risk of complications, including miscarriage, preeclampsia, and perinatal mortality. 
• Infections: Infections may account to up to 15% of early miscarriages and up to 66% of late miscarriages. Most infections are preventable and treatable. Pregnant women usually benefit from regular screening for chlamydia, ureaplasma, cytomegalovirus, and toxoplasma.
• Low progesterone causing miscarriage or luteal phase defect: Low progesterone and luteal phase defect may both make conception more difficult because they prevent the uterine lining from becoming “sticky” enough to sustain a healthy pregnancy. This can impact implantation or cause early miscarriage.
• Diabetes: Uncontrolled diabetes can put the expectant mother at a higher risk of miscarriage, stillbirth, birth defects, or excess birth weight. 

Can low progesterone cause miscarriage?

Low progesterone can be, but is not always, the cause of early miscarriage. If an embryo is chromosomally abnormal or a woman is experiencing an ectopic pregnancy, progesterone supplementation will not be able to prevent miscarriage.

However, if an embryo and pregnancy are healthy, insufficient progesterone production can cause failed implantation or early miscarriage during the first trimester. Additionally, studies have shown that progesterone supplementation drastically reduces the risk of miscarriage and symptoms of low progesterone in pregnancy including bleeding during early pregnancy for suffered multiple early losses. 

How do I improve my progesterone levels?

If you know you have low progesterone, you first may want to try to improve your levels naturally. There are a few things that might help:

• Seed cycling: Seed cycling is a way to balance your hormones by adding certain seeds to your diet during certain phases of your cycle. 
• Diet: Studies show that diet can affect our hormones. Malnutrition or an unhealthy diet can both wreak havoc in our endocrine system. Adopting a healthy diet with less sugar, limited intake of processed foods, lean protein, healthy fats, and lots of greens may promote hormonal balance.
• Herbal supplements: Herbal supplements such as maca, vitex, and ashwagandha have been shown to improve progesterone production and overall hormone balance.

If you have tried these methods and are still experiencing low progesterone levels, we recommend consulting your doctor or considering Proov Path to Pregnancy. He or she may be able to provide prescription-strength progesterone support.

While low progesterone can unfortunately cause early miscarriage, it is entirely treatable and the fix is often simple!