How long is a full-term pregnancy?

Sleeves of saltines. Phone calls with mom. Doctor’s visits. There are so many ways to measure time when you’re expecting. Another? Gestational age—the measure of how far along you are in your healthy pregnancy.

Most doctors use gestational age to measure the amount of time you’re pregnant. For many, gestational age can be a bit of a head-scratcher. Technically, you’re pregnant the day you conceive. However, there are no definite physical indicators of conception, making the exact date difficult to pinpoint. For this reason, doctors use the first day of your last menstrual period, a measurable date, to start the clock on gestational age. Pregnancies are considered full-term at the gestational age of 37+ weeks.

Trimesters

You can easily determine your due date by finding counting 40 weeks forward from the first day of your last menstrual period. You can also skip the counting altogether and use the SneakPeek Pregnancy Due Date Calculator.

To determine your current gestational age, count the number of weeks forward from the first day of your last period. Remember that if you haven’t concluded your full 12th week, for instance, then you are technically still in the 11th week of pregnancy.

Many of your gestational milestones will relate to your pregnancy trimesters, which are:

• First trimester – 1st week through 12 weeks
• Second trimester – 13th week through 27 weeks
• Third trimester – 28th week through 40 weeks (and beyond if applicable!)

In each trimester, you can expect new challenges and exciting changes. Let’s explore them week by week.

Weeks 1 through 4

Welcome to the beginning of your pregnancy journey! Here’s the thing: you aren’t pregnant. Yet.

As we’ve noted above, doctors technically start the pregnancy clock before you actually conceive your child. So, during the first week of “pregnancy,” you’re on your period, possibly experiencing:

• Cramps
• Bloating
• Vaginal Bleeding
• Mood swings

Around the end of week 2, you will ovulate, which can present with symptoms of cramping or tingling. During ovulation, your ovary will release an egg, which will journey from your fallopian tube to your uterus. If, by chance, it comes across a sweet-talking sperm along the way—it’s on.

They give each other that look, they embrace, and before you know it, they’re taking a one-way trip to Fertilization Station.

In weeks 3 and 4 of your gestational period, the fertilized egg continues the journey to your womb, where it will float around for a few days as it divides into cells. Pregnancy officially begins about 6 days after sperm meets egg, when the fertilized egg (which is now made up of hundreds of cells) implants itself into your uterine lining and earns the title “embryo.”

Implantation can feel a bit irritating and resemble a light period. Some of the first signs of pregnancy might include these symptoms:

• Light spotting
• Abdominal cramping

Weeks 5 through 8

It’s happening! Your period was a no-show and a positive pregnancy test (and a second, third, and fourth test) confirmed the news. In fact, your positive pregnancy test picked up on some recent hormonal changes in your body. After implantation, you start producing Human Chorionic Gonadotropin (hCG), the chemical that boosts your body’s levels of the pregnancy-supporting hormone progesterone.

As you field an influx of progesterone and begin to plot with your hubby how you’ll share the good news with your parents, you enter the embryonic stage of your early pregnancy, the period in which your baby’s major internal organs begin developing. This stage begins around week 6 and lasts for about 5 weeks.

During weeks 5 through 8, some uncomfortable early pregnancy symptoms may crash the “we’re pregnant!” celebrations. These are caused by an increase in pregnancy hormones and an increase in blood volume to support your baby’s growth.

Early pregnancy symptoms can include:

• Nausea
• Heartburn
• Food cravings and/or aversions
• Acne
• Breast tenderness and swelling
• Fatigue
• Mood swings
• Frequent urination
• Bloating
• Constipation

Weeks 9 through 12

Growing another human is a pretty heroic task. It requires strength, care, and selflessness. The thing about heroic tasks? They can leave you feeling depleted, exhausted, and in the case of pregnancy, sick to your stomach.

During weeks 9 through 12, you might be feeling some of the same discomfort that popped up weeks prior. That said, your nausea may worsen, and your breasts may continue to change, including nipple and areola breast changes during pregnancy. Your areolas may grow bigger and darker in preparation for breastfeeding, and you might need to up-level your cup size (again). No need to worry, these are all signs your pregnancy is going well in the first trimester

These final weeks of your first trimester may also be marked by the arrival of a few new symptoms, including:

• Round ligament pain – These lower belly aches and pains can occur as your abdomen stretches to make space for your growing baby.
• Vaginal discharge – Boosted blood flow and estrogen can result in increased vaginal discharge.
• Noticeable veins – Because you’re pumping more blood through your body, your veins might appear larger and more visible.

Weeks 13 through 16

Welcome to your second trimester! You may have dealt with your fair share of bedridden days and nauseated nights during your first trimester, but now, you get to embrace your second-trimester glow-up.

For pregnant woman, weeks 13 through 16 mean the end of some of the nausea, fatigue, and indigestion that mark the first trimester.

As your body has had some time to adjust to the elevated hormone levels, you might begin to experience:

• Increased energy
• Increased sex drive
• Increased appetite

Some consider the second trimester to be the “honeymoon phase” of pregnancy. You’ll likely feel more like yourself during this time, and you might even elicit some envious stares with your shiny, thick head of hair (thanks to the increased level of hormones that encourage hair growth and ramped up blood flow in your body).

But, increased blood flow might mean more than a streak of good hair days. It can also cause:

• Nasal stuffiness
• Swollen gums
• Dizziness

Weeks 17 through 20

Your baby is growing, and so is the anticipation. By week 17, your little one is the size of a pomegranate. And by week 20, the length of a banana.

You’re growing, too—even if an app can’t tell you what size fruit you are. During these weeks, you might feel:

• Like your skin is itchy – As your skin stretches to accommodate your growing baby, it might become thinner, more delicate, and itchy, especially around your expanding boobs and belly. You might also start to notice the formation of stretch marks. These are natural and inevitable for some women, but you can mitigate them by keeping hydrated, inside and out. That means drinking plenty of water and using a hydrating moisturizer regularly.
• Like you’re gaining weight – It’s common to gain 1 to 2 pounds per week throughout the second trimester. So if you’re leaning into your stretchy pants, don’t stress. Besides, everyone’s too busy admiring your radiant skin and luscious locks to notice.
• Like your dreams are . . . strange – Last night you dreamt that your house was made of blueberry muffins. What gives? The combination of hormones and stress might make your dreams a little bit wacky.
• Like you can feel your baby move – If you think you can feel your baby dancing, it might be because she is! Pregnant women typically begin to feel their babies moving around the 5-month mark.

Weeks 21 through 24

During these next few weeks, as you pick out paint samples for the nursery, you’ll likely feel more of the same symptoms you experienced during weeks 13 through 20. You may also encounter a handful of new symptoms as your pregnancy journey progresses. These include:

• Colostrum leakage – As you near the end of the second trimester, you might experience occasional leaks from your breasts. This is colostrum—tiny droplets of early milk. Its production means your milk ducts are good to go in case someone gets here early. However, not all women experience leakage, so don’t worry if this isn’t one of your symptoms.
• Back pain – It’s common for your back to begin aching as you get further along in your pregnancy. This is because of the added weight and pressure that comes with carrying a baby. (Note to all partners: it’s time for a back massage!)
• Braxton-Hicks contractions – You might begin to feel some uncomfortable squeezing in your uterus or belly during these weeks. Don’t worry—this is just Braxton-Hicks contractions (i.e. your womb rehearsing for labor). Although these contractions are believed to start as early as 6 weeks into gestation, they’re usually not felt until the second or third trimester.
• Belly button changes – You wake up one morning, and that life-long innie is suddenly an outie. It’s not the start of a sci-fi film, but rather, a result of your growing belly. But don’t panic—in most cases, these outies go back innie after your baby is born.

Weeks 25 through 28

Now, your baby is starting to take up space. A lot of space. Space that you used to use for, oh, I don’t know, breathing.

In addition to backaches, leaky boobs, and Braxton-Hicks contractions, you might experience an increase of uncomfortable symptoms as you head into the third trimester, including:

• Shortness of breath
• Frequent urination (from baby crowding your bladder)
• Leg cramps
• Trouble sleeping
• Hemorrhoids
• Swelling and fluid retention
• Aches and pains

Weeks 29 through 32

The finish line is close. And thank goodness. Because for many pregnant people, the third trimester can bring a hefty dose of discomfort from:

• Increased Braxton-Hicks contractions
• Hemorrhoids and constipation
• Leaking urine while laughing or sneezing

The silver lining? You’re getting that much closer to meeting your little one. Every back pain, leg cramp, and yep, even hemorrhoid, will be worth it.

Weeks 33 through 36

As you move through your ninth month of pregnancy, you’ll likely experience more of the same bodily discomfort, trouble sleeping, and aches and pains.

Other symptoms you might encounter include:

• Increased vaginal discharge
• Headaches
• Overheating
• Varicose veins
• Abdominal pressure
• Increased pressure on the bladder

Your baby might also drop down lower in your womb at some point during these weeks as your body prepares to give birth. This process, called lightening, is essentially your body’s way of positioning your baby lower into your pelvis. While some women experience lightening several weeks before labor, others don’t experience it until several hours before labor.

The process of lightening can cause some pelvic discomfort (and make you need to pee, stat!), but it should relieve some of your heartburn and shortness of breath.

Weeks 37 through 40

Your birth plan is set, your hospital bag is packed, and you’re only a few weeks away from your baby’s arrival.

As you near the end of your pregnancy journey, you might experience:

• Increased pressure on your pelvis
• Spotting
• Braxton-Hicks contractions
• Sharp vaginal pains as your cervix begins to dilate

There are some non-physical symptoms to watch for, too. You might begin to feel anxious to get the show on the road—and that’s normal. This journey has been long and demanding on your body, mind, and spirit. Try to get some R&R while you wait for your baby’s arrival (think: your favorite snacks, relaxing walks, and reality TV).

Busying yourself can help, too, especially if you’re one of the many pregnant people who feels a strong urge to nest—to get everything squared away and settled at home in advance of your little one’s arrival.

Learn Your Baby’s Gender Weeks Sooner with SneakPeek

Pregnancy is many things—exhilarating, exhausting, strange, and unique to every individual. Knowing what to expect from week to week, as well as who to expect, can calm those feelings of uncertainty that affect every parent-to-be.

That’s why we created the SneakPeek At-Home Early Gender Prediction Test—the #1 OBGYN-recommended at-home gender test. Simply collect your DNA sample, and you can learn the gender of your little one as early as week 7 of your pregnancy, with clinically-proven over 99% accuracy¹.

So don’t wait until weeks 18 to 20 to discover if you’re having a little he or a little she. Join the over 1 million moms who found out sooner with SneakPeek®.