The second trimester lasts 14 weeks, running from week 14 through week 27 of pregnancy. The American College of Obstetricians and Gynecologists (ACOG) defines it precisely as 14 weeks and 0 days through 27 weeks and 6 days. That puts it squarely in the middle third of a full 40-week pregnancy, spanning roughly months four, five, six, and the beginning of month seven.
When It Starts and Ends
The second trimester begins at the start of week 14, counted from the first day of your last menstrual period. It ends at the close of week 27. The first trimester covers everything up through 13 weeks and 6 days, and the third trimester picks up at week 28 and continues until delivery.
You may see slight variation depending on the source. Some pregnancy apps or websites round the cutoff to “week 13” or “week 28,” but the clinical standard from ACOG draws the line at 14 weeks 0 days to 27 weeks 6 days. If your provider or app seems off by a week, it’s likely just a rounding difference rather than a real disagreement.
Why It’s Called the “Easiest” Trimester
For many people, the nausea and deep fatigue of the first trimester fade once the second trimester begins. Energy levels often bounce back, and anxiety tends to ease as the risk of early pregnancy loss drops significantly. That reputation as the comfortable middle stretch is well earned for most, though not everyone gets the same experience. Some people continue feeling sick well into the second trimester, or they develop new symptoms that replace the old ones.
What Happens to Your Body
Your uterus expands noticeably during these 14 weeks, and your belly starts to look unmistakably pregnant. Don’t worry if the bump takes a while to show, especially in a first pregnancy. Breasts continue to grow as well.
Hormonal shifts bring a collection of changes you might not expect. A dark line can appear down the center of your belly (called linea nigra), and brownish or grayish patches may show up on your face. Stretch marks can develop along the belly, breasts, thighs, or buttocks. Tiny spider veins sometimes become visible on the face and legs. Rising blood volume can make the inside of your nose swell, leading to stuffiness or nosebleeds.
Other common second trimester symptoms include:
- Lower back pain from the growing uterus and hormonal changes loosening your joints
- Braxton Hicks contractions, a mild tightening in the belly that comes and goes and is not true labor
- Leg cramps, especially at night
- Dizziness from shifts in blood flow and circulation
- Increased vaginal discharge, usually clear or white
- Dental sensitivity, including gums that bleed more easily when brushing or flossing
Sleeping on your side rather than your back becomes important during this trimester because it supports better circulation to both you and the baby.
How the Baby Grows
The second trimester is a period of rapid growth. At week 14, the baby measures about 3.5 inches from head to rump and weighs roughly 1.5 ounces. By the end of the trimester at week 26, the baby is around 9 inches long and nearly 2 pounds. That’s a jump from the size of a lemon to something closer to a large eggplant.
Here’s a snapshot of growth at key points:
- Week 16: about 4.75 inches, 4 ounces
- Week 20: about 6.3 inches, 11 ounces
- Week 24: about 8.25 inches, just over 1.3 pounds
During this stretch, the baby develops fingerprints, begins to hear sounds, practices swallowing, and starts responding to light. Facial features become more defined, and a layer of fine hair covers the body.
When You’ll Feel the Baby Move
Most people first feel fetal movement somewhere between 16 and 24 weeks of pregnancy. If this is your first pregnancy, you may not notice anything until after week 20. The sensation is often described as a flutter or a feeling like butterflies in your stomach. It’s subtle at first and easy to mistake for gas. Over the following weeks, those flutters turn into unmistakable kicks and rolls.
Key Tests and Checkups
The anatomy ultrasound is one of the most anticipated appointments of pregnancy. It typically happens around weeks 18 to 20 and gives a detailed look at the baby’s organs, limbs, and overall development. This is also when many parents learn the baby’s sex if they choose to.
Between weeks 24 and 28, most pregnant people have a glucose screening test to check for gestational diabetes. This involves drinking a sweet liquid and having blood drawn about an hour later. If the initial screening result is elevated, a longer follow-up test confirms whether gestational diabetes is present.
Weight Gain During These Weeks
For people who started pregnancy at a healthy weight, the general guideline is to gain about 1 pound per week through the second and third trimesters. If you started out overweight or obese, the recommended pace is closer to half a pound per week. These are averages, not exact targets for every single week. Some weeks you’ll gain more, some less. Your provider tracks the overall trend rather than any single weigh-in.
An increased appetite is one of the hallmark second trimester changes, which makes sense given how quickly the baby is growing. Eating regularly and staying hydrated helps manage both the hunger and some of the more uncomfortable symptoms like dizziness and leg cramps.