18 Weeks Pregnant: Common Symptoms, Baby Development, And Size

18 Weeks Pregnant: Common Symptoms, Baby Development, And Size

15 Dec 2016 | 10 min Read

Sudeshna Chakravarti

Author | 759 Articles

If you are 18 weeks pregnant, then you are in the middle of your second trimester, and four-and-a-half months pregnant. During this time, your energy levels start going back to normal, and you may start to feel your baby’s movements actively. In this week, you may also experience certain pregnancy symptoms and bodily changes, such as body pain and leg cramps, which can be eased with slight to moderate exercises and walking.

In this post, we give you all the crucial information about the 18th week of pregnancy and discuss your baby’s development and size and other bodily changes that you can expect.

Your Baby’s Development at 18 Weeks

At 18 weeks of pregnancy, your uterus will expand even more in size to accommodate your growing baby. Most of your baby’s crucial bodily systems will continue to develop with some of them being almost fully functional. Your baby will also learn new skills while they are in the womb, and in this week, you can expect them to begin yawning. 

Keep reading to learn more interesting facts about your baby’s development and size in the 18th week of pregnancy.

How Big is Your Baby at 18 Weeks?

At 18 weeks of pregnancy, your baby will be as big as a bell pepper, and usually, weigh around 190gms (6.7 ounces), and measure 14.2cms (5.6 inches) in length. Additionally, your baby’s growth continues with the development of different parts of their body.

If you want a deeper insight into your baby’s development and size, you can follow the pregnancy week-by-week posts published by BabyChakra, which are information-rich, and discuss all important pointers on foetal development.

Foetal Development at 18 Week Pregnancy

18 weeks pregnant
During the 18th week of pregnancy, your baby’s retina will develop and they will respond to a beam of light / Image source: Medical News Today

At 18 weeks of pregnancy, you can expect your baby to achieve the following milestones in terms of their growth and development in the womb.

  • Skin: Your baby’s skin will be wrinkled and coated in a waxy substance called vernix. The fine hair covering their skin, referred to as lanugo, will also be clearly visible through ultrasound.
  • Eyes: Their retina is still developing, and it can respond to a beam of light.
  • Ears: Bones of the middle ear and nerve endings from the brain are developing, so your baby might begin hearing your voice during this time.
  • Bones: Your baby’s bones begin to harden in the clavicles and legs.
  • Fingers: Unique fingerprints are formed by this time.
  • Lungs: During this time, breathing passages develop to form the bronchial tree.
  • Nerves: Your baby’s nerves get fully covered with a tissue coating called myelin.
  • Mouth: Sucking and swallowing movements start by this time. Some babies may also get hiccups.
  • Nails: Your baby’s finger and toenails will be developed to the tip.
  • Liver and pancreas: These organs begin to produce secretions by the 18th week of pregnancy.
  • Genitals: You can see their genitals through an ultrasound scan.

Common Symptoms That You Will Experience This Week

At 18 weeks of pregnancy, you will experience symptoms like body aches and pains, and the urge to pee frequently. In some cases, the symptoms experienced during this time are similar to the early signs of pregnancy. You might notice:

  • Weight gain: An average weight gain of 500gms per week during the second trimester is considered safe by doctors. However, if your BMI is less than 18.5 and greater than 24.9, then the recommended weight gain should be between 250gms-450gms. Make sure to determine your BMI during your prenatal visit, and follow necessary diet changes to maintain optimal weight.
  • Constipation: The progesterone hormone relaxes the muscles in your digestive tract, causing your food to remain in the tract for a longer time for maximum absorption of nutrients into the bloodstream. However, this may slow down your intestinal movements, leading to constipation.
  • Frequent urination: The growing uterus puts a lot of pressure on your bladder, causing you to pee frequently.
  • Backache: As the growing uterus shifts the body’s centre of gravity, more pressure is exerted on your lower back, causing backache.
  • Dizziness: The increasing size of the uterus compresses your blood vessels and limits the blood flow to your brain, causing lightheadedness and fatigue. Sometimes, staying hungry for a long time can also contribute to dizziness. Hence, make sure to drink plenty of water and eat properly to enhance your health.
  • Stuffy nose: Hormonal changes can increase the blood flow to the mucous membranes, making them soft and swollen, and causing a stuffy nose and congestion. 
  • Heartburn: Due to the growing uterus, the stomach is pushed towards the diaphragm, and the gastric fluids are pushed upwards toward the osephagus, causing heartburn. The best way to prevent this condition is by avoiding fatty and spicy foods.
  • Leg cramps: The growing uterus causes your blood vessels to compress, leading to leg cramps. This symptom is usually experienced at night and may hinder your sleep. You can use a pain-relief oil to soothe the cramps or support your legs with pregnancy pillows for relief and comfort.
  • Varicose veins: Excess blood flow to the lower part of your body leads to swelling and pooling of nerves in your legs, causing varicose veins.
  • Edema: At 18 weeks of pregnancy, your body retains a lot of water, giving rise to a condition called edema, which causes swelling in your legs and hands.
  • Trouble sleeping: Due to different body aches like leg cramps and backaches, you may have trouble sleeping. Use a pillow around your stomach and between your legs for comfort and support.

Your Body at The 18th Week of Pregnancy

18 weeks pregnant
During this time, the line nigra becomes more prominent due to skin pigmentation

The bodily changes that you experience during this time will be more rapid as compared to the first trimester. Common physical changes that occur during the 18th week of pregnancy are:

  • Growing belly: Your tummy protrudes during this time, and you can even feel the uterus between your pubic bone and the navel.
  • Enlarged breasts: Your breasts become swollen and tender as your body prepares them for breastfeeding.
  • Linea nigra: The linea nigra, which is the line going down from your navel to the pubis gets darker due to pigmentation.
  • Shinier hair: Changes in your hormones may reduce hair fall, and make your strands appear fuller and shinier.
  • Stretch marks: At 18 weeks of pregnancy, the growing uterus stretches your skin, causing stretch marks on your belly.

When you are 18 weeks pregnant, you may also experience certain emotional changes, such as mood swings and anxiety. You may also have weird dreams due to childbirth or pregnancy-related fears and anticipations.

18 Weeks Pregnant Belly

At 18 weeks, your belly will appear bigger and more protruded. During this time, you may also begin to feel strong foetal movements. These movements might feel like a swish, flutter, or roll. Oftentimes, you may not be able to identify your baby’s movements and mistake their kicks for gas. However, fret not, as your baby grows, they become more active, and the movement inside becomes more prominent too.

In case you want to know the exact week your baby starts kicking, you can use a pregnancy month calculator to find out more details and also track your little one’s developmental progress. 

Do You Need an Ultrasound at The 18th Week Of Pregnancy?

When you are 18 weeks pregnant, your prenatal visit will include a blood pressure check and weight check. The doctor will also measure the height of the fundus and suggest other lab tests like maternal serum screening and urinary tests. 

Additionally, you will also have an ultrasound scan during this visit. This screening also referred to as an anomaly scan, lets you have a close look at your baby’s organ developments, gives you information about the placental position and appearance, and also an insight into the amount of amniotic fluid surrounding the baby.

Self-care Tips for 18 Weeks Pregnancy

18 weeks pregnant
You should focus on consuming nutritious and wholesome foods that fulfil your caloric requirements

We have listed a few self-care tips that you should follow during the 18th week of your pregnancy.

  • Drink plenty of water and stay hydrated.
  • Follow a healthy lifestyle and consume home-cooked meals.
  • Have smaller meals at frequent intervals. Include wholesome foods like fruits, veggies, grains, milk, and dairy products in your diet.
  • Engage in light physical activities like walking to boost your energy levels.
  • Keep stress at bay and get enough rest.
  • Wear loose, breathable clothes, and switch to comfortable shoes or slippers.
  • Consume fibre-rich foods to avoid constipation.


  • Make sure that you aren’t missing any appointments with your doctor.
  • Research about childbirth and baby care, and if needed take educational classes.
  • Start reading maternity books, and engage in activities that make you happy. For instance, come up with a list of possible baby names.

Pregnancy Checklist at 18 Weeks

A set of checklists for the 18th week of pregnancy:

  • Set an appointment with the sonographer for your next appointment scan.
  • Schedule the next prenatal appointment with your ob-gyn.
  • Make a list of questions that you are curious about, and discuss those with your doctor during the next appointment.
  • Narrow down a list of baby names.

What to Ask Your Doctor?

By the time you reach the 18th week of pregnancy, you may be curious to know more about your baby’s development inside the womb. Some crucial questions to ask your doctor are:

  • Is my baby growing healthily inside the womb?
  • Do I need to get additional tests to understand my baby’s development and growth?
  • Are you going to add more medications to my prescription?
  • Is my current diet sufficient to fulfil my calorific needs per day?
  • Is there anything that I should avoid eating?
  • Can I engage in physical activities?
  • What are my symptoms going to be like in the next week?


By 18 weeks of pregnancy, your baby will be almost the size of a bell pepper, and you can also expect slight movement in the womb. In addition, you will experience physical changes like enlarged breasts and emotional changes like anxiety and mood swings. 

Make sure to take proper care of yourself, and if you feel any uncomfortable symptoms like vaginal bleeding or severe vomitting, consult your ob-gyn immediately. 


What should I be worried about at 18 weeks pregnant?

If you do not feel any foetal movement even in your 18th week of pregnancy, then you should consult your doctor for more advise and check your baby’s developmental progress. 

Is 18 weeks considered 5 months pregnant?

No. 18 weeks of pregnancy is considered four-and-a-half months pregnant.

Is my baby fully formed at 18 weeks?

While some of your baby’s body parts become functional during this time, it takes longer than 18 weeks for your baby to develop in the womb.

Can you feel your baby kick at 18 weeks?

Yes, you can feel strong kicks at 18 weeks of pregnancy. You can also expect your baby to be more active now and in the coming weeks.

How often should my baby move at 18 weeks?

There is no set number of normal movements that you should be feeling. This is because every baby is different and their foetal movement may differ too. Just remember, you should experience some amount of foetal movement each day. 

How can I wake my baby in the womb?

You can talk to your baby, sing a lullaby, or turn on some music to wake your baby in the womb. A short burst of exercise can wake them up too.

Also read:

19 weeks pregnancy symptoms: Nearing the 19th week of pregnancy? Here are some common symptoms that you might experience.

Ovulation calculator: Check out this post to learn the benefits of using an ovulation calculator while planning your pregnancy.

Featured image: Pexels.com



Suggestions offered by doctors on BabyChakra are of advisory nature i.e., for educational and informational purposes only. Content posted on, created for, or compiled by BabyChakra is not intended or designed to replace your doctor's independent judgment about any symptom, condition, or the appropriateness or risks of a procedure or treatment for a given person.