When you’re pregnant, your body’s firing on all cylinders. Hormones surge, heart rate picks up, and blood supply swells. And we’re just getting started.

Given all that internal hustle and bustle, it’s easy to see why many women reach for tank tops and fans during pregnancy, even in the midst of a Minnesota January.

So why, then, are you shivering instead of sweating? And is feeling cold during pregnancy normal?

Moms-to-be commonly run more hot than cold, but feeling chilled doesn’t necessarily mean there’s anything wrong with you or your baby. Your inner temperature control system may simply be overly efficient at cooling the hardworking engine that is your pregnant body. Or you may have a very treatable, often self-limiting condition (more on that later).

We know it’s easy to let your imagination run wild about every ache and ailment you experience during pregnancy — and because we know you’re wondering, we want to tell you up front that feeling cold is not a sign of pregnancy loss.

Take a deep breath as you reach for that blanket. There are several not-so-uncommon reasons why pregnancy might be giving you the cold shoulder, and knowing their causes and symptoms can put you one step closer to getting some peace of mind — and possible treatment.

Low blood pressure

So you’re not the hot pregnant mess you thought you’d be, with hot being the operative word? It might be your blood pressure.

While some pregnant women have high blood pressure — sometimes dangerously high — about 10 percent of moms-to-be actually have low blood pressure, or a reading of 90/60 or lower.

Low blood pressure in pregnancy often stems from the extra circulatory demands your body encounters as it tries to work up enough blood for you and your developing baby.

Many pregnant women with low blood pressure don’t have symptoms, but when your body’s working hard to get enough blood pumped to its tissues and organs — including the all-important uterus and placenta — you might notice cool, clammy skin as well as:

  • nausea
  • dizziness
  • fainting
  • blurred vision
  • weak but fast pulse

See your doctor if you’re experiencing any of these symptoms, as they’ll need to be evaluated.

But if you have low blood pressure readings and feel fine, relax. You won’t require any treatment. According to the American Heart Association, blood pressure usually readjusts to normal by about the 24th week of pregnancy.

Anemia

Anemia occurs when your body doesn’t produce enough oxygen-carrying red blood cells. And since your body runs on oxygen, you can see where that’s problematic for just about every system in your body, including the one that warms you up and cools you down. In developed countries like the United States, 14 percent of women become anemic during pregnancy.

Pregnant women are particularly prone to a type of anemia called iron-deficiency anemia. Your body uses iron to make red blood cells. When you’re pregnant, you need twice as much iron as normal to supply enough oxygen-rich blood to you and your baby.

If you don’t have enough of the mineral stored in your body from your pre-pregnancy days (remember those, when ankles weren’t cankles and jeans had zippers?) or get it through your diet, you’ll become anemic. This is especially true in the second and third trimesters, when your baby is furiously growing.

One of the hallmarks of the condition is cold hands and feet. Other symptoms include:

  • feeling weak
  • pale skin
  • an irregular heartbeat
  • shortness of breath

You’ll be tested for anemia periodically throughout your pregnancy, but if you’re in between appointments, let your doctor know if you have any anemia symptoms.

Hypothyroidism

Hypothyroidism, or having an underactive thyroid, is a condition in which your body doesn’t make enough thyroid hormones. That can happen if you have a certain autoimmune disease (called Hashimoto’s thyroiditis) in which your body attacks your thyroid.

Hypothyroidism also occurs when there’s damage to your thyroid (for example, from radiation) and even nutritional deficiencies (especially a lack of iodine). Many women have mild hypothyroidism that goes unnoticed until the heavy hormone demands of pregnancy kick in.

Thyroid hormones are essential for your baby’s brain and nervous system development. They also fire up your metabolism and help control your heart rate and body temperature. Without enough of these hormones, you might feel:

  • cold
  • tired
  • depressed
  • constipated

Hypothyroidism affects up to 5 percent of all pregnant women. If you have any of the symptoms, let your doctor know so you can get tested.

Lack of sleep

You’re waking up two, three, even five times a night? Yeah, we’re not surprised. Pregnancy doesn’t stop just because it’s 2 a.m. The backaches, heartburn, and frequent bladder breaks that plague you during the day occur at night, too.

That all makes getting a decent chunk of restful sleep — something that’s essential for the regulation of body temperature — a downright nightmare.

Sleep problems are most common in early pregnancy, thanks to hormonal changes, and later in pregnancy, when you’re trying to find a comfortable sleep position with something akin to a bowling ball between your legs.

Anxiety

We get it: Giving birth and then spending the next 20 or so years of your life putting the physical, emotional, and financial needs of someone else ahead of your own is kind of a big deal. Which is why pregnancy can produce anxiety, an emotion that can kick your body’s fight-or-flight mechanism into gear.

To get your body ready to make a move, blood diverts from nonessential organs like your skin to more important ones like your heart, and that can leave you feeling cold. Other symptoms of anxiety are:

  • nausea
  • sweating
  • racing heartbeat

According to a 2019 review of studies, anxiety affects almost one quarter of pregnant women. In a 2015 study, nearly 16 percent of pregnant women reported high levels of anxiety.

Infection

If you have some general achiness and lethargy along with a chilled feeling, you might be coming down with a viral or bacterial infection. Chills are actually a chemical response to the invading germs and your body’s defensive response to them.

Symptoms vary depending on what sort of infection you have (you might have congestion with a respiratory infection, nausea with a stomach one, etc.). Contact your doctor if you develop a fever or you’re concerned for any reason about how you’re feeling.

Low blood pressure

Unless it’s severe, low blood pressure during pregnancy generally isn’t treated. Keeping yourself hydrated and moving slowly from a prone or sitting position to standing can help ease dizziness and prevent fainting.

Anemia

Most prenatal vitamins contain iron and help protect against anemia, but for some women it may not be enough.

  • Your doctor may prescribe an iron supplement.
  • In severe cases, you may be admitted to the hospital for iron given intravenously.
  • It’s hard to get all the iron you need from your diet, but adding more iron-rich foods like lean red meat, poultry, and beans may help.

Hypothyroidism

Hypothyroidism is successfully treated with thyroid hormone replacement drugs. These medications are safe for you and your baby, although they shouldn’t be taken at the same time as your prenatal vitamin since minerals in the vitamin can make it harder for your body to absorb the hormone.

Lack of sleep

Practice good sleep hygiene:

  • Get your fluids in during the day to limit nighttime trips to the bathroom.
  • If heartburn is a problem, avoid spicy, fried, or acidic foods at dinner.
  • Don’t drink caffeinated beverages after early afternoon.

Anxiety

You’ve heard the tales of three-day-long labors. You might already be worrying about juggling work, family, and Common Core math. Our point? Childbearing and rearing is anxiety producing. Talking to your partner or a close friend or family member (especially one who’s been-there-done-that) can help. Your doctor can also refer you to professional therapists.

Infection

Potential infections need to be evaluated by your doctor. In the meantime, practice self-care:

  • Get extra rest.
  • Drink plenty of fluids.

Even though you may be in the minority, don’t sweat feeling cold during pregnancy. There are some perfectly normal reasons why you may be reaching for that sweater. Talk to your doctor about your concerns and get tested and treated if necessary.