Pregnancy symptoms and why they happen

A Comprehensive List of Pregnancy Symptoms—Including Ones No One Told You About

10 min read

While pregnancy affects everyone differently, it’s usually not all glowing skin, healthy hair and good-for-you diets. In fact, some pregnancy side effects can make you feel terrible—and we’re not just talking about morning sickness although, yep, that affects many women and it can be more debilitating than movies would have you believe. Here’s a comprehensive list (organized in typical order of appearance) of pregnancy symptoms (and why they happen!), including plenty that no one has ever told you about (and that lot’s of pregnant people before you were surprised about when it happened to them). 

(This list is lengthy so it should be noted that you almost certainly will not experience all of the below. You might not experience any of them! That’s the thing about pregnancy: everyone has a different experience and even the same person will have a different experience from pregnancy to pregnancy. Instead of viewing this as the worst to-do list ever, consider it a resource so you’re not completely surprised when you start getting nosebleeds.)

Excess saliva

When it happens: First trimester. 

Why it happens: Although rare, those who do report excess saliva also tend to have morning sickness. While we don’t know exactly why this happens, some experts believe it’s a protective factor against stomach acid that can have negative effects on the teeth and throat—and it’s likely thanks to pregnancy hormones (which you’ll be hearing a lot about in this post).

Food aversions

When it happens: Early pregnancy, starting around seven weeks and can persist for the entire pregnancy for some women. In the majority of cases, the aversions will subside, near the end of the first trimester, when the early pregnancy nausea reduces.

Why it happens: Huge hormonal swings occur during the first trimester; hCG (the pregnancy hormone) soars to an all time high during the first three months of pregnancy, along with estrogen and progesterone. This combination can contribute to increased metabolism, and glucose clearance, making early pregnancy prime for hypoglycemia, nausea, and fatigue.

I Forgot to Take My Prenatal While Pregnant 

Nausea (a.k.a., Morning sickness or—let’s be honest—all-day sickness)

When it happens: Pregnancy-related nausea can start as early as six weeks. Most of the time (about 75 percent) it will subside by the beginning of the second trimester. Unfortunately, some will experience it their entire pregnancy and a small number of women will suffer Hyperemeisis (severe nausea) and have to seek medical treatment.

Why it happens: The cause of morning sickness is not totally known—it may be caused by low blood sugar or the rise in pregnancy hormones or estrogen. It can be made worse by stress, being overtired, eating certain foods or motion sickness.

What are the symptoms of severe morning sickness (hyperemesis gravidarum)?

If you think you might have Hyperemesis, look for these symptoms as they may indicate you need to be treated at the hospital with IV fluids to restore hydration and medication to relieve nausea:

  • Vomiting more than three times a day
  • Dehydration (including little-to-no urine production, dark-colored urine or dizziness with standing)
  • Losing five or more pounds (especially within the first trimester)

The Best Natural Remedies for Pregnancy Nausea 


When it happens: At the onset of pregnancy and typically lasts until the end of the first trimester.

Why it happens: There are a few reasons why many people experience constipation during pregnancy:

  • An increase in progesterone: Progesterone relaxes your intestines so that they don’t work as hard to squeeze waste out through your body. The slowdown allows your body more time to absorb nutrients and water from the food you eat. The longer the food remains in your bowel the more time your large intestine (colon) has to absorb the moisture out of it, resulting in dried out and hard-to-pass bowel movements.
  • The growing fetus: A growing fetus makes your uterus heavier and this extra weight can put more pressure on your bowel, making it harder for waste to travel out of your body.
  • The iron from your prenatal vitamin: The iron you’re getting from your prenatal vitamin helps your body make the blood needed to circulate oxygen throughout your (and your baby’s) body. Too much iron can make it harder for bacteria in your bowel to break down food, though. 
  • Your changing habits: Your diet, the amount of fluids you drink each day and how much exercising you do all play a role in making you constipated (or not). Make sure to eat lots of fibre, drink lots of water and get a daily dose of exercise to help with this pregnancy side effect.

Gas and bloating

When it happens: Early pregnancy, but often lasts the entire pregnancy.

Why it happens: When you're pregnant, your body churns out progesterone, a hormone that relaxes all your muscles, including the ones in your digestive tract. These relaxed muscles slow down digestion, which can lead to more-than-usual gas, bloating, burping and flatulence—especially after you've had a big meal.

Change in bra size, breasts and rib cage

When it happens: Breast size increase can usually occur at the onset of pregnancy, while rib cage circumference increase is more typically seen in the second and third trimesters. 

Why it happens: Breast tissue is responsive to hormonal changes, and the tissue develops and enlarges during pregnancy to prepare for breastfeeding. Even if you don’t breastfeed and after your breastfeeding journey is complete, many people still note significant changes in size and shape to their pre-baby breasts. Rib-cage size increase occurs a bit later on in pregnancy and can be attributed to both the hormonal relaxation of ligaments and an increasingly expanding uterus which puts continual pressure on your rib cage, causing it to expand.

Changes to taste and smell

When it happens: Starts in early pregnancy and will often last the entire pregnancy.

Why it happens: Dysgeusia (a change in your sense of taste) during pregnancy is likely caused by pregnancy hormones. Studies suggest that as many as two-thirds of pregnant women become more sensitive and reactive to the scents around them when they’re pregnant.

Shortness of breath

When it happens: First trimester—but can persist throughout the entire pregnancy.

Why it happens: High progesterone levels cause pregnant people to breathe deeper and faster. The rise in progesterone begins early in pregnancy, and the shortness of breath it causes can come as a surprise. While shortness of breath can be worrisome, most of the time it is harmless and due to the normal changes of pregnancy (including the increase in uterus size, which creates compression on the rib cage and diaphragm). As blood volume increases during pregnancy, and iron is in high demand, many women can become iron deficient. If iron stores are low in the second or third trimester, shortness of breath can be a side effect.

Frequent urination

When it happens: Can start as early as the first trimester and last the whole pregnancy.

Why it happens: As your uterus begins to expand (by about 1,000 times by the time you deliver), it creates pressure on the bladder. Plus, your body’s fluid levels start to increase during pregnancy, so the amount of urine you release will increase as well.


When it happens: Usually the second or third trimester—but it can happen in the first trimester.

Why it happens: Gastroesophageal Reflux Disease (GERD, the fancy name for heartburn) is reported in up to 80 percent of pregnancies. It’s likely caused by an increase in maternal estrogen and progesterone that relaxes the valve at the entrance to the stomach, meaning it doesn’t close as it should. The result? Stomach acids move up into the esophagus.


When it happens: Often in the second and third trimesters.

Why it happens: Most nosebleeds are caused by an increase in blood volume and blood-vessel expansion, and hormonal changes related to pregnancy. These are usually alarming but harmless (and happen to up to 20 percent of pregnant people). 

Pelvic pain

When it happens: Usually the second or third trimester.

Why it happens: Pelvic Girdle Pain (PGP) or Symphysis Pubis Dysfunction (SPD) is a collection of uncomfortable symptoms caused by stiffness of the pelvic joints or the joints moving unevenly at either the back or front of your pelvis. As your baby grows in the womb, the extra weight and the change in the way you sit or stand will put more strain on your pelvis. You are more likely to have PGP if you have had a back problem or have injured your pelvis in the past, or have hypermobility syndrome, a condition in which your joints stretch more than normal. Additionally the body produces a hormone called relaxin, which increases joint mobility during pregnancy to accommodate for the growing baby, and prepare for delivery. Most people don't notice the effects of relaxin, but it can cause pelvic pain in some people during pregnancy. You may feel pain when using the stairs, getting out of cars, changing positions in bed or standing on one leg.

How to Exercise While Pregnant 

Dental sensitivity

When it happens: At any time during pregnancy, but often more pronounced later on.

Why it happens: Pregnancy gingivitis is caused by an increase in estrogen and progesterone levels. These are essential hormones that help the fetus grow and develop, but they also cause increased inflammation of your gums. Although the exact way this happens isn’t clear, healthcare providers think it may be due to either increased blood flow or changes in the microbiome that make it harder for your body to respond to plaque bacteria.

Change in shoe size

When it happens: The second or third trimester, sometimes through to postpartum..

Why it happens: Relaxin and progesterone released during pregnancy will loosen the pelvic ligaments, but these hormones can also make the long arch ligament in the sole of your foot more lax. This, in combination with weight gain, can cause an increase in shoe size. (Typically one-half to one full size increase can be seen, and this is usually permanent.)

Back pain

When it happens: At any time during pregnancy, but especially during the second and third trimesters. 

Why it happens: When breast tissue and the stomach begin to expand, your centre of gravity shifts, putting more pressure on your back—which has to make up for the work your abs aren’t doing.

Varicose veins

When it happens: Usually in the second or third trimester.

Why it happens: Varicose veins happen in pregnancy when the uterus applies pressure to the large vein (the inferior vena cava) that carries blood back to the heart from your feet and legs. During pregnancy, hormone changes and the weight of your growing baby make you more susceptible to varicose veins, thanks to:

  • Higher levels of progesterone, which relaxes blood vessel walls and decreases valve function
  • Increased volume of blood in your body
  • Pressure on the blood vessels in your pelvis which can change blood flow in your pelvic region and legs

All of these forces make it more difficult for blood to travel against gravity from your legs to your heart.

What to Pack in Your Hospital Bag 

Leg cramps

When it happens: Often at night during the second and third trimesters.

Why it happens: Leg cramps—painful involuntary muscle contractions that typically affect the calf, foot or both—are common during pregnancy and are often due to less exercise than usual or electrolyte or mineral deficiency. Taking appropriate calcium and magnesium can help.

Carpal tunnel syndrome

When it happens: Second or third trimester.

Why it happens: When you are pregnant, your hormones cause fluid to build up in your body and your blood volume almost doubles by the end of pregnancy. All of this can cause swelling and put pressure on the carpal tunnel. 

Lightning crotch

When it happens: Third trimester.

Why it happens: That sudden, sharp vaginal or pelvic pain you may feel late in pregnancy is referred to as Lightning Crotch. It’s not serious or a sign of labor—it’s likely due to the baby putting pressure on the nerves around the lower part of your uterus. (But, if it lasts more than a few seconds, be sure to tell your doctor as it could signal something more serious.) It can feel a little different from person-to-person, but most often this pregnancy symptom manifests as:

  • Sharp, shooting pain in the vagina or pelvic area that lasts only for a moment
  • Stinging or a pins-and-needles sensation in the same region
  • Brief but intense pelvic pain that’s stronger and shorter than menstrual cramps

Nasal congestion and snoring

When it happens: Anytime during pregnancy, but it tends to be worse in the third trimester. 

Why it happens: Nasal congestion during pregnancy can be caused by inflammation of the mucous membranes lining the nose, and increased blood flow to the nasal passages and enlargement of the nasal veins also play a role. 

Itchy Skin

When it happens: Third trimester.

Why it happens: Intrahepatic Cholestasis of pregnancy is a liver condition that can occur in late pregnancy. The condition triggers intense itching, but without a rash. Itching is usually on the hands and feet but also can occur on other parts of the body. The exact cause of cholestasis of pregnancy is unclear, but pregnancy hormones, genetics and the environment may all play a role.

How to Find a Pregnancy-Safe Sunscreen 

Sciatic or shooting leg pain 

When it happens: Usually during the third trimester, but it can occur at anytime during pregnancy. 

Why it happens: During pregnancy, levels of the hormone relaxin increase. This hormone helps prepare your pelvis for childbirth by relaxing ligaments and widening your hips. As your belly grows and ligaments loosen, your center of gravity shifts, which can cause the sciatic nerve to get pinched or irritated.