How and Why Your Body Changes During Pregnancy - Baby Chick

How and Why Your Body Changes During Pregnancy

pregnancyUpdated February 14, 2022


Pregnancy brings a lot of changes: changes to your lifestyle, your home, and even your career and relationships. But quite possibly the biggest are those body changes during pregnancy. Everyone knows the obvious change of a baby bump, but what many people don’t know is that every day, your inner organs and functions are constantly changing, growing, or altering their functions to accommodate you and your baby.

If you are pregnant, looking to become pregnant, or just curious about what goes on inside, here are the major body changes during pregnancy—and why they happen.

How and Why Your Body Changes During Pregnancy

Your Uterus Grows

As mentioned, we all know our bellies grow, but did you know that inside, your uterus is expanding to make room for your baby? Your uterus will grow so large during the second trimester that it will no longer fit comfortably in its’ usual spot in the pelvis. Instead, it will travel above your belly button and continue to expand upward. By the time you’re getting close to the due date, your uterus will be as big as a watermelon. But don’t fret—after baby is born, it will “involute” back to its original size and find its way back into your pelvis—until the next baby, that is.

Why does this happen? This one is simple. Your uterus grows to hold your growing baby! As the uterus expands and pushes your other organs out of the way, it makes a larger home for baby to feel comfortable in until she is ready to enter the world.

Your Blood Pressure Changes

Your blood is doing all sorts of crazy things the moment you get pregnant. For instance, your plasma increases in volume, causing your heart rate to speed up (do you feel out of breath all the time?). Hormones produced relax your blood vessels, causing a slight decrease in blood pressure at the beginning of your pregnancy. A small reduction in your blood pressure is normal, but blood pressure that drops too low may be a cause for concern. Try to sleep on your side as much as possible to avoid a larger drop in blood pressure. In addition to the blood pressure, your body will also experience an increase in blood volume and blood vessels to prepare for birth and baby, which will bring your blood pressure back up.

Why does this happen? The development of new blood vessels and the relaxation of blood vessels by the hormone progesterone cause a decrease in blood pressure for some at the beginning of pregnancy. As pregnancy progresses and stress on the body increases, in combination with increased blood volume and cardiac output, blood pressure can begin to rise later in pregnancy.

You Grow a Cup Size (or Two or Three)

Your breasts getting bigger is one change that can happen almost instantly for some women (and not at all for others!). But, for many, larger breasts are often the first of the body changes during pregnancy that people notice. In addition to the growth, women will also experience tender breasts, larger nipples, and darker areolas. And this change continues until baby is born—as you approach your due date, your breasts will truly begin to prepare for breastfeeding. For example, you may notice some leakage from the nipples and an even bigger increase in cup size.

Why does this happen? You can also blame this one on hormones. Estrogen and progesterone increase dramatically during pregnancy, and those two hormones are directly related to our breast size and milk production.

Your Hormones Go Crazy

Speaking of hormones, you can pretty much blame them for the majority of your body changes during pregnancy. Your hormone, or endocrine, system is working double time. This will cause your basal metabolic rate to increase (some women may already be aware of this change while they’re trying to conceive), which causes your appetite to increase, feelings of fatigue, and even occasional hot flashes to appear. It will also increase glucose levels, decrease calcium levels, and increase prolactin. Be sure you take the appropriate prenatal vitamins to help counteract any negative elements these changes bring.

Why does this happen? Your entire body is changing to make room for a growing human—and your hormones regulate these body changes during pregnancy. All these changes are necessary, though—they help baby grow, play a big part in milk production, and ensure a healthy pregnancy.

Your Respiratory System Speeds Up

Feeling tired and out of breath? You can thank your changing respiratory system for that. Your rib cage will begin to spread, and as your uterus grows, your diaphragm will also be displaced. This, in addition to the increase in blood flow, will cause your need for oxygen to increase, and you may feel yourself taking deeper, fuller breaths.

Why does this happen? It’s no longer just you who needs your oxygen! The fetus needs lots of oxygen, too. So do the uterus and placenta. With all this oxygen to spread around, your respiratory system takes note and increases its rate to ensure everyone gets what they need.

Your Gastrointestinal System Gets Funky

All your gastrointestinal organs are making changes—many of which you’ll notice. Are you feeling constipated? This is because your digestion is slowing. As your uterus enlarges (yes, it’s the uterus’ fault yet again!), it pushes the stomach and intestines out of place, causing your digestion to slow. Also, the hormone progesterone increases, which aids in relaxing our organs. This can cause heartburn and acid reflux.

Why does this happen? The uterus is making room for baby, which means the gastrointestinal organs need to move aside. As they move, your digestion will slow, and as progesterone gets released, your organs will relax, causing flatulence, constipation, upset stomachs, and heartburn.

Take care of yourself, mama! All of these body changes during pregnancy can leave you feeling elated, beautiful, tired, sad, cranky, and joyful all in one day! Remember that you’re growing a person and that your body is an amazing system.

For more, listen to our podcast episode 33, where we talk about surprising body changes during pregnancy.

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