First trimester: Your changing body

First trimester: Your changing body

Although you will not look pregnant from the outside, your body is hard at work making significant changes. It's growing a placenta, adding breast tissue, increasing blood volume, making amniotic fluid, and creating a baby. These are natural changes and you can trust your body to know what to do. Listen to your body's needs and adjust your lifestyle when necessary.

Physical changes


It's common to feel very tired during the first trimester. Your body uses a lot of energy to grow a baby and has to adjust to being pregnant. To limit your exhaustion:

  • Try to rest when you feel the most tired.
  • Run errands early in the day so you can take a nap in the afternoon.
  • Try to arrange resting during a part of your lunch break.

Reduce your commitments so you can go to bed early enough to get a good night's sleep. This tiredness usually lessens as pregnancy progresses. Many pregnant people feel much more energetic during their second and third trimesters.


It is thought that a hormone produced by the placenta and the increased level of estrogen causes the nausea and vomiting in pregnancy. Low blood glucose, an empty stomach and an increased sensitivity to odors can make it worse.

Although it's often called "morning sickness," the nausea can happen at any time of the day or night. It usually starts between weeks four and six and decreases dramatically after weeks 13 and 14. Morning sickness is not an illness or a sign of a problem with your pregnancy. However, it is important that you are able to keep liquids down. If you can't, call your health care provider.

Try these tips to deal with nausea:

  • Eat rice cakes, saltines or dry toast before you get out of bed.
  • Get out of bed slowly.
  • Eat small amounts of food often. Do not overeat.
  • Try not to drink liquids with meals. Sip liquids between snacks and meals.
  • Eat a small snack before returning to bed if you get up during the night.
  • Try drinking teas or cold beverages made with fresh ginger or peppermint. Ginger gum and mints, or ginger aromatherapy can also be helpful..
  • Eat what sounds good to you.
  • Try small amounts of proteins such as cheese sticks or peanut butter with crackers.
  • Try wearing acupressure wristbands designed to stop seasickness.
  • Ask your health care provider about taking a vitamin B6 supplement.

Breast tenderness

Your breasts may become fuller and quite tender. Pregnancy brings changes that prepare your body for breastfeeding. The increased blood flow and growth of milk-producing cells are part of this change. Wearing a supportive bra with wide, nonelastic straps may help you feel more comfortable.

What do you know about breastfeeding? Take the breastfeeding quiz to find out!

Although breasts get bigger during pregnancy, milk production does not require large breasts. Pregnant people with small breasts can produce all the milk their babies need.

Need to urinate often

Increased hormone levels, more waste products to eliminate, and the pressure of your growing uterus on your bladder add up to more trips to the bathroom. You can help improve bladder control by doing Kegel exercises. This will help prevent or decrease leaking a little urine when you laugh or sneeze.

Feeling dizzy and lightheaded

The hormone progesterone causes blood vessels to relax. This makes it easier for blood to "pool" in your legs and feet. Try these things to feel less lightheaded or dizzy:

  • Change positions slowly when you sit up or stand. This helps avoid sudden changes in your blood pressure. When standing, gently shift your weight from foot to foot.
  • Avoid lying flat on your back. This position increases pressure on major blood vessels and makes it harder for blood to circulate.
  • Drink eight to 10 glasses (at least 64 ounces) of water a day. Your body needs this water to maintain its increased blood volume.

Even with these physical changes you can still feel terrific. Many pregnant people feel healthy and invigorated during pregnancy.

Source: Allina Health Patient Education, Beginnings: Pregnancy, Birth and Beyond, eighth edition, ob-ah-90026
First Published: 10/04/2002
Last Reviewed: 12/06/2021