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You’ve made it through your first trimester. Congratulations! This one should be a bit easier. But just because you may be more comfortable, doesn’t mean things are slowing down. If anything, at 4 months pregnant, they’re speeding up.

We’ll walk you through what is going on inside your pregnant belly in terms of baby’s growth and development and what you can expect for yourself. Many consider this trimester to be the best of the three, so give your tummy a light pat and enjoy it!

Table Of Contents

Welcome To The Second Trimester

 4 months pregnant

At this point, your sweet little passenger is about the size of an avocado. Hopefully, all of that nausea and discomfort of the first trimester will be subsiding this month, and you can relax into your new reality. But what is happening with your baby? Let’s take a look.

4 Months Pregnant: Your Baby

After four months in your belly, your little one gets even busier. At about five inches long and five ounces, they may be little, but they’re mighty and getting mightier by the minute.

Eye Spy

During this month, your baby’s eyes are developing rapidly. Their eyelids, eyebrows, and eyelashes are being formed. Although still closed, their tiny peepers can even perceive some light.

Facial Features

Hair is growing and your baby’s face is coming more into focus (though their skin is nearly translucent at this stage). Enter the cute factor: This month, baby can start to make faces, yawn, stretch, and suck their thumb.

Speaking of baby’s thumb, their fingers and toes have gotten more definition by now, and even their fingernails are forming. If that makes you smile, how about this: Baby’s teeth and bones are also becoming denser (though you won’t get to see those pearly whites for a while now)!

Getting Active

You may start to feel baby’s little kicks when you’re 4 months pregnant. If not, don’t worry. This will all happen soon enough. Your little bodybuilder is gaining more and more muscle and is busy trying out their limbs and flexing their arms and legs.

At this point, your OBGYN may be able to hear baby’s heartbeat with a Doppler.

Gender Shows

Do you want to know the gender of your little one? You’re in luck. This month, baby’s reproductive organs are developing, and their genitals may be visible when you get an ultrasound.

Hearing Voices

Not only are baby’s own vocal cords developing, but they’re starting to hear you from inside your belly, thanks to their developing ears. So sing them a lullaby or read them some stories!

 Mom 4 months pregnant in the nursery

4 Months Pregnant: Your Body And Mind

Now that we know what’s happening with baby, let’s take a look in the mirror. You’re probably starting to show, and you’ve maybe even had to trade those button flies for elasticized waistbands. This month will be a whirlwind of change.

Getting Bigger

If no one noticed in the first trimester, your stealth days are numbered. This month is often the turning point as baby needs more room in the womb.


When 4 months pregnant, you’re gaining the necessary weight for your baby to thrive.


As the second trimester begins, your breasts are also getting bigger. You may find yourself shopping for a larger bra that will give you more support. And your breasts also may feel extra sensitive.

Tummy Time

With baby taking up residency in your belly, it’s no surprise that you’re feeling some changes in your tummy.

Less Nausea

As we mentioned, when the second trimester begins, the nausea subsides. Whew!

More Heartburn

On the flip side, moms-to-be at 4 months pregnant may start to experience heartburn. This is thanks to both hormonal changes and the fact that baby is pressing against your stomach.

 Mom having a picnic near the lake

Food Cravings

Here’s a fun one! This is when you start scouring through the fridge to make yourself a pickle and ice cream sundae! In the fourth month of pregnancy, your body may be craving some surprising combinations.

You also might experience the flip side of cravings: food aversions. Common aversions tend to group around foods with a strong smell or unappetizing texture. The good news is your tumultuous taste buds should calm down by the end of your pregnancy.

Bathroom Changes

Having a baby means there will be some changes when it comes to using the bathroom, none of which are particularly pleasant.


First of all, by month four of your pregnancy, you may be feeling a little stopped up. Constipation during pregnancy is thanks to the progesterone hormones that relax your intestinal muscle. This means your dinner slow-walks itself through your system.

If you’re taking iron supplements, they can be the cause of your constipation, too. Be sure to pour an extra tall glass of water if taking this supplement.


During the second trimester, you also might be noticing vaginal discharge. This milky substance is totally normal and is the result of increased blood flow to the tissues and pregnancy hormones. 

Mustela stretch marks products

Skin Shift

During the fourth month of pregnancy, you might find that your skin looks a little different, with pronounced veins and the start of stretch marks.

Varicose Veins

The hormone changes in pregnancy can make you more susceptible to varicose veins. With more progesterone, an increased volume of blood in your body, and pressure on the blood vessels in your pelvis, it’s harder for blood to travel from your legs to your heart.

Usually, varicose veins are harmless, and they’ll disappear after baby makes their debut. However, there are ways to reduce your symptoms, including exercise, massage, and compression stockings.

Stretch Marks

Although most see them a bit later in the pregnancy, some women start to see stretch marks in month four as their bellies start growing. Mustela’s Stretch Marks Set, which includes Stretch Marks Cream and Oil, can help.

Sensitive Smile

You can take all the selfies you want, but you should know that during this time, your gums and teeth can become extra sensitive. Your gums may bleed when you brush and floss your teeth thanks to pregnancy hormones.

Stuffy Nose

You might want to have a box of tissues close at hand. Those pregnancy hormones are at it again, causing the swelling of your mucus membranes. This will result in a pesky post-nasal drip.

Vivid Dreams

Once you’re off in dreamland, things may feel a little more real. Vivid dreams are often reported at this stage of pregnancy.

4 Months Pregnant: Doctor Visits

At 4 months pregnant, your doctor will assess your progress and check in about any questions or concerns you might have.

If you haven’t already, you will also be offered a blood test to determine baby’s risk for Down’s syndrome, trisomy 13, trisomy 18, and neural tube defects, such as spina bifida. If you have an increased risk, the doctor may suggest an amniocentesis.

At this prenatal visit, your doctor will also measure your uterus to track baby’s growth. As we had mentioned, your child’s gender may also be apparent, so if you’d like to know, your doctor can share the good news.

Your doctor will also check baby’s heart rate, and if you’re lucky, you may get a good listen. At this visit, you’ll also get a weigh-in and a blood pressure check and will be asked to leave a urine sample, just to be sure your sugar and protein levels are normal.

Besides visiting your OBGYN, it’s a good time to check in with your dentist, especially if your gums bother you. And, because your days will be getting busier, you should go ahead and get a cleaning.

 Mom apply stretch marks cream on 4 months pregnant belly

Surviving And Thriving In Your 4th Month

This second trimester is off to a strong start. You know what baby’s doing in there — building muscles and bones and even making a few funny faces.

You also know what’s happening with your body — gaining weight, getting strange cravings, and everything else from your teeth to your toes.

As anxious as you may be to meet your little one, just take it day by day and try to enjoy it. Also, watch what you eat and stick to the good stuff as much as possible. Rest is also important for your ever-changing body.

At 4 months pregnant, you’re one-third into the magical ride that is pregnancy. And there are a lot of things going on this month, with both you and your baby.

Now and for the months to come, get some comfort with Mustela’s specially formulated products, like our stretch mark serums, oils, and creams. The hydrating formulas nourish and moisturize, providing you with the perfect dose of pampering you most certainly deserve.

Soon, you’ll be taking care of your little one’s skin outside of the womb as well!