What is it?
The transformations over the course of an entire pregnancy are incredible. Your body undergoes a series of changes to support your growing baby, literally from head to toe. While the most obvious physical change is the growth of your belly, there are many other internal changes that you may not see but impact nearly every part of your body. As your body adapts to support your pregnancy, hormone fluctuations cause a cascade of events from the cellular level to the creation of an entirely new organ (the placenta) to prepare for growing a new life.
Some of these changes might be welcomed – many people enjoy watching their belly grow and their hair increase in thickness, while others may be uncomfortable and awkward, like acne and nosebleeds. These temporary changes can be a lot to take in, but they don't all occur at once, and most resolve after pregnancy. It is important to remember that everyone's pregnancy is different, and some may experience more or less of these changes than others.
What to expect
Pregnancy is a time of great change for your body—weight gain is a normal (and essential) part of this process.
How much your body changes during pregnancy will vary from person to person, and every pregnancy is different. Weight gain is the change that feels the most dramatic, with approximately half of the weight you gain in pregnancy due to the growing baby, placenta, amniotic fluid, and uterus. Increased blood volume, breast tissue, and an accumulation of water, fat, and protein make up the rest of the weight that’s gained throughout each trimester. Most healthcare providers will give you a range for what’s typical weight gain for your body during pregnancy.
These estimated averages can give you an idea of how your body may grow and change over the course of your pregnancy—but it’s important to remember that every body is unique.
- Your breasts grow 1 to 3 pounds (about 0.5 to 1.4 kilograms)
- Your growing uterus adds 2 pounds (about 0.9 kilograms)
- Your placenta at birth is about 1.1 pounds (about 0.5 kilograms)
- Your uterus contains 2 pounds (about 0.9 kilograms) of amniotic fluid
- Increased blood volume adds 3 to 4 pounds (about 1.4 to 1.8 kilograms)
- Increased fluid volume contributes 2 to 3 pounds (about 0.9 to 1.4 kilograms)
- Energy stored as fat adds about 6 to 8 pounds (about 2.7 to 3.6 kilograms).
- The weight of your fetus adds an average of around 7 or 8 pounds (about 3 to 3.6 kilograms) by the end of your pregnancy.
While a changing body and a growing midsection are the biggest visible changes, there are many more incredible transformations that take place throughout your pregnancy:
Blood volume increases by 50%
Your body’s blood volume increases up to 50% throughout your pregnancy. This means your heart has to work harder to pump more blood throughout your body, which causes your heart rate to increase by approximately 10-20 beats per minute. This can also lead to sinus pressure and congestion, swelling and edema, bleeding gums, and nosebleeds due to expanding blood vessels. After birth, your blood volume and heart rate will return to pre-pregnancy volume around 2 weeks after delivery.
Fluctuating hormones and complex physical changes can tax your brain, which can lead to forgetfulness, difficulty recalling words, and trouble finding things. This is commonly called “pregnancy brain.” Research shows that the brain actually changes during pregnancy in the areas that control social cognition, perhaps to make adjustments for maternal attachment.
Stretch marks are a common skin change that affects up to 90% of pregnancies. They appear as streaky lines across your belly, breasts, butt, and thighs. Stretch marks are caused by the rapid stretching of your skin as your fetus grows and, contrary to what the market will try to sell you, research shows that they cannot be prevented with products (although oils and balms can help soothe your skin). They are typically most noticeable during the third trimester and can fade over time.
Melasma, often called ‘the mask of pregnancy,’ is a type of hyperpigmentation that causes dark patches to appear on your face. Melasma is caused by a rise in estrogen and progesterone, which cause an increase in melanin production. It occurs in up to 20% of pregnancies and often appears on the cheeks, nose, and sides of the face. Melasma typically fades naturally after giving birth and disappears (with treatment) within a year. Sun exposure can also make melasma darker and take longer to fade, so using adequate sun protection is important.
Acne is a common skin condition that can occur anytime, but it's especially common during pregnancy. Various factors can cause acne, but when it develops or worsens during pregnancy, it is most likely the result of fluctuating hormone levels. Pregnancy acne typically goes away postpartum.
Linea nigra appears as a dark vertical line down the center of your abdomen during pregnancy. It is caused by the darkening of the linea alba, a thin fibrous tissue that runs down the abdomen. Not everyone will experience this, but if you do, it usually develops during the second trimester and may get darker as you get closer to your due date. This typically recedes post-pregnancy and returns to its pre-pregnancy state.
Read here for a deep dive into skin changes during pregnancy and what you can do about them.
Rhinitis, or a constant stuffy nose, is common during pregnancy. It’s estimated that 20-32% of all people will experience nasal congestion at some point during their pregnancy. The exact cause of pregnancy rhinitis is unknown, but the leading theory is that hormonal changes during pregnancy (including an increase in placental growth hormone, which stimulates the growth of the fetus) cause swelling of nasal mucous membranes and excess mucus production. Increased blood volume also puts pressure on blood vessels in the nose and sinuses, which can also contribute to congestion.
Read here for a deep dive into Pregnancy Induced Rhinitis and what you can do about it during pregnancy.
Your hair may grow faster and become thicker. This is because hormonal changes cause hair to remain in a growth phase for longer than normal, causing you to shed less hair. Contrary to popular belief, thicker hair in pregnancy is not due to prenatal vitamins. After delivery, the drop in hormone levels signals a shift that makes hair follicles shed hair faster. This is known as postpartum hair loss (Telogen effluvium), typically occurring in months two through four after delivery. While hair shedding can be significant, you will not go bald, and your hair will grow back over time.
The placenta and ovaries release a hormone called relaxin during pregnancy, which causes joints and ligaments in the body to become more flexible. This benefits the pelvis by allowing the midsection to widen as your fetus grows. However, this can also cause instability in your joints, which can cause aches and pains. This also means you may need to be more cautious with your movements and physical activity during pregnancy because muscles and ligaments are easier to strain.
When should I be worried?
While all the changes outlined above are typical, your healthcare provider can help if anything seems troubling or you are experiencing pain or discomfort affecting your daily life.
Changes in your body can trigger different emotional responses for everyone. Body image and the cultural and social pressures to look a certain way or “bounce back” to your pre-pregnancy body once you’ve given birth are often unrealistic and not reflective of the realities of female physiology through this incredible process. If concerns about your body image during pregnancy and postpartum are challenging for you, consider speaking with your healthcare provider or a therapist who can help you navigate your expectations.