The second trimester is the phase between Weeks 13–28 of pregnancy. As the fetus continues to grow and develop, a person may experience noticeable changes to their body, such as a bump developing.

During the second trimester, the fetus’s organs, bones, and functions continue developing. The pregnant person may experience symptoms such as stretch marks and lower back pain, but fatigue and nausea may ease.

This article explains what to expect in the second trimester, how the fetus develops, and health tips.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

Was this helpful?
A pregnant women in her second trimester trying to tidy her toddler's hair -2.Share on Pinterest
Trevor Williams/Getty Images

The second trimester starts in Week 13 of pregnancy and continues until Week 28.

The second trimester may feel different for everyone, but most people may start to feel less tired than in the first trimester, and nausea may also ease.

Learn more

Learn more about pregnancy trimesters.

Share on Pinterest
Design by Jeremiah McNair.

During the second trimester, the fetus continues developing and growing throughout the weeks:

Weeks 13–16

  • lower limbs develop
  • the bones harden, particularly the long bones
  • lungs start to develop tissue to allow the exchange of oxygen and carbon dioxide during breathing after birth
  • toenails form
  • neck definition develops
  • hearing begins to develop
  • the skin is still thin but will soon begin to thicken

Weeks 17–20

  • the digestive system is now working
  • the area of the brain that manages motor movements fully develops
  • in females, the vagina and uterus begin to develop
  • lanugo, which is soft, downy hair, begins to cover the body
  • people will be able to see the fetus’s eyes, nose, and lips on an ultrasound

Weeks 21–24

  • fat begins to form underneath the skin
  • the ridges of fingerprints and footprints start developing in the hands and feet
  • blood vessels become visible, making the skin wrinkled and reddish
  • development of the sucking reflex occurs
  • kicks and turns start getting stronger

Weeks 25–28

  • eyelids can open and close
  • development of the nervous system occurs
  • more fat develops, making the skin appear smoother
  • the fetus may respond to loud sounds with sudden movements, pulling in the arms and legs
  • the lungs are fully developed and produce surfactant, a substance to allow breathing after birth (but the lungs cannot yet work outside of the uterus)

Pregnant people may experience the following changes in their body during the second trimester:

  • The body may ache, such as in the abdomen, back, groin, hips, ribs, and thighs.
  • Stretch marks may develop on the abdomen, breasts, buttocks, or thighs.
  • The skin around the nipples may darken.
  • Patches of darker skin may develop on the face, typically in a symmetrical pattern over the forehead, cheeks, nose, or upper lip.
  • A line may form on the skin from the belly button to the pubic hairline.
  • Carpal tunnel syndrome may develop, causing tingling or numbness in the hands.
  • A person may experience itchy palms, soles of the feet, or abdomen.
  • A person may develop swollen ankles.

Tips for general health in the second trimester include the following:

Learn about what to eat in the second trimester.

During the second trimester, people may have the following tests during their antenatal visits:

  • Maternal blood screening: This test screens the blood for certain substances to check for the risk of congenital anomalies (also known as birth defects).
  • Ultrasound: Between Weeks 18–22 of pregnancy, people may have an ultrasound to monitor the growth and development of the fetus and check for congenital anomalies.
  • Glucose screening: Doctors recommend this to check for gestational diabetes. It typically takes place between Weeks 24–28 of pregnancy.
  • Amniocentesis: A healthcare professional will take a sample of amniotic fluid to check for congenital anomalies or genetic conditions. People may have amniocentesis between Weeks 15–20 of pregnancy.

Certain complications can develop in the second trimester of pregnancy. For example, preeclampsia is a condition that can occur during the second trimester. Signs to look out for include severe or sudden swelling or rapid weight gain. A person will need to contact a doctor straight away if they have any symptoms of preeclampsia.

It is also possible to develop liver problems during the second trimester. If a pregnant person experiences itching along with any of the following symptoms, they should contact a doctor. A combination of these symptoms may indicate a liver problem:

A person should also contact a doctor if they experience any of the following symptoms:

Things people may want to consider in the second trimester include:

  • the type of birth they ideally want, such as whether they would prefer to give birth in a hospital
  • whether they want to know the sex of the fetus or want to wait until the birth to find out
  • telling an employer about the pregnancy and deciding on parental leave
  • attending antenatal appointments and taking antenatal classes
  • who they would want to have as a birthing partner

Learn about announcing a pregnancy.

During the second trimester, the fetus will continue to grow and develop, and people may start to see a bump. Toward the end of the second trimester, people will start to feel the fetus move.

People may also feel less fatigue and nausea during this phase than in the first trimester.

Keeping active, eating a balanced diet, and attending all recommended screenings and antenatal checkups can help people manage their health during the second trimester.