18 Weeks Pregnant: Baby, Body and What to Expect

Week 18 at a glance

At 18 weeks, your baby is often about 5.5 to 5.9 inches long, roughly the size of an artichoke. Hearing is developing, and your baby may start to notice sounds, including your heartbeat.

18 weeks pregnant is about 4 months. You are in month 5 of pregnancy and the second trimester.

Your baby at 18 weeks

The Size of an Artichoke and Your Baby's Hearing

At 18 weeks, your baby's hearing is developing quickly. Your baby may begin to notice sounds, including your heartbeat.

What is happening this week

Your baby is often about 14 to 15 cm (5.5 to 5.9 inches) long. The hearing system is maturing, so your baby may start to pick up sounds, especially lower and more rhythmic ones.

Your heartbeat and the sound of blood flow may be heard.
Your baby may respond to loud or sudden noises.
Movements are becoming more noticeable, and some people start to feel light fluttering at this stage.

If you don't feel movements yet, that can still be normal. Early movements are often described as light fluttering or bubbles and can be hard to tell apart from other sensations at first. Many people feel movement between 18 and 22 weeks, and first-pregnancy movement often comes later.

How this week may feel

At 18 weeks, many people feel better after early pregnancy nausea, and the belly is becoming more noticeable. Heartburn, stretching in the belly and hips, and tiredness can still happen, especially later in the day.

Call your provider right away if you have bleeding, severe belly or pelvic pain, fever, fluid leaking from the vagina, or a sudden change in how you feel. Call 911 or go to the nearest emergency room for heavy bleeding, fainting, or trouble breathing. Once you feel your baby move regularly, tell your provider if the movements change noticeably.

See week 18 in 3DNova shows how your baby grows each week and keeps a symptom log for your doctor. Try Nova

Your body at 18 weeks

Early Baby Movements at Week 18

The First Flutters

Feeling your baby move for the first time is one of the most memorable moments of pregnancy. Many people describe it as fluttering, like butterflies, or like tiny bubbles popping.

When will you feel movement?

At 18 weeks (about 4.5 months), your baby is active enough that you may start to notice movement. Every pregnancy is different. If you don't feel anything yet, that is common, and it doesn't necessarily mean something is wrong.

Early movements are often mistaken for digestion, such as gas or stomach rumbling.
If this is your first pregnancy, you may not notice movement until closer to 20 weeks or later.
The position of the placenta can cushion movements, making them harder to feel.

You may notice movement more when you are resting or sitting quietly, such as in the evening. Many providers suggest paying attention to your baby's movement during these calm times.

When to contact your provider

Contact your OB-GYN or midwife right away if you notice a sudden decrease in your baby's movement or a major change from their usual pattern, even if it is early in pregnancy. Many providers start teaching movement counting in the third trimester, usually around 28 weeks, so ask yours when they want you to begin tracking. Call your provider or go to the nearest emergency room if you have bleeding, fluid leaking, severe abdominal pain, or you are concerned about your baby at any time.

Common symptoms at 18 weeks

Early fluttering movements

You may start to feel light flutters, bubbles, or a tapping sensation, often between 18 and 22 weeks. If you do not feel anything yet, that is common, especially if this is your first pregnancy. Lying down quietly after a meal can help you notice movement more easily.

Growing belly

Your uterus is now near your belly button, so your midsection may look rounder and feel firmer. Loose, comfortable clothing with a soft waistband can feel more pleasant as your body changes.

Backaches

Shifts in your posture and the growing weight in front can strain your lower back. Gentle stretches, a supportive pillow when sitting, and wearing supportive shoes often help.

Stuffy nose or nosebleeds

Extra blood flow and hormone changes can dry or swell the lining of your nose. A humidifier at night and saline spray can ease the stuffiness, and tell your care team if nosebleeds keep happening.

Dizziness when standing quickly

Blood vessels widen during pregnancy, which can make you feel lightheaded if you stand up fast. Rising slowly from sitting or lying down and staying hydrated can help.

Skin changes

You may notice a darker line down your belly or patches of darker skin on your face. These changes often fade after pregnancy, and sunscreen can help keep them from getting darker.

Your week 18 checklist

Drink water throughout the day and keep a water bottle nearby. Schedule or keep your next prenatal visit if it is due. Check whether your insurance covers prenatal care and any tests you are offered. Try a short daily walk or gentle stretching if your body feels up to it. Write down any questions about movement, sleep, or food to bring to your next visit. Think about who you would like to have support you through labor and birth.

Tests and appointments

Anatomy ultrasound. Many people are offered a detailed ultrasound around 18 to 22 weeks to check the baby's growth, organs, and body structures.
Maternal blood screening. Some clinics offer a blood test around this time to screen for certain chromosomal conditions, and you can choose whether to have it.

For your partner: You can help by learning about the early movements together, so you can share the excitement when they start. Offering to handle some chores, like cooking or laundry, can ease fatigue and back strain.

Questions about week 18

How many months is 18 weeks pregnant?

18 weeks pregnant is about 4 months. You are in month 5 of pregnancy and the second trimester.

What trimester is 18 weeks?

Week 18 is in the second trimester. The first trimester runs through week 13, the second from week 14 to 27 and the third from week 28 until birth.

What is happening with the baby at 18 weeks?

At 18 weeks, your baby is often about 5.5 to 5.9 inches long, roughly the size of an artichoke. Hearing is developing, and your baby may start to notice sounds, including your heartbeat.

Is it normal not to feel the baby move at 18 weeks?

Yes, it is common not to feel movement yet. Many people first feel flutters between 18 and 22 weeks, and it can take longer for first pregnancies. Your care team can check on your baby at your next visit if you have concerns.

What do baby flutters feel like?

Early movements are often described as light bubbles, popcorn popping, or a gentle tapping. They may feel different from the stronger kicks that come later. Movements can come and go, and some days may feel quieter than others.

Can I exercise at 18 weeks of pregnancy?

Many people can continue or start gentle activity like walking, swimming, or stationary cycling. Check with your care team first, especially if you have health conditions. Stop and talk to them if you feel pain, bleeding, dizziness, or shortness of breath.