When should I start using a pregnancy tracker app?

You can start as soon as you get a positive pregnancy test, typically around week 4 or 5. The earlier you begin, the more complete your tracking history will be. Some women start after their first prenatal appointment when they have a confirmed due date from an ultrasound.

Do pregnancy tracker apps share my data?

It depends on the app. Some pregnancy trackers collect and share personal health data with third parties for advertising or analytics. Others store data locally on your device. Always check the privacy policy before entering sensitive information. Pregnancy App stores tracking data on your device and does not require an account or login.

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Pregnancy Tracker — Follow Your Pregnancy Week by Week

Q: What is a pregnancy tracker?

A pregnancy tracker is a tool — usually a mobile app — that follows your pregnancy from conception to birth. It shows your current week of pregnancy, baby's size and development, expected symptoms, upcoming milestones, and countdown to your due date. Most trackers update weekly with new information matched to your gestational age.

Q: Are pregnancy tracker apps accurate?

Pregnancy trackers provide general developmental timelines based on established medical research about fetal growth. They are accurate for broad milestones — when organs form, when the baby can hear, when the lungs mature. They cannot account for individual variation. Every pregnancy develops at a slightly different pace, so treat tracker information as a guide, not a diagnostic tool.

Q: What is the most accurate pregnancy tracker app?

No single app is definitively the most accurate because all reputable pregnancy trackers draw from the same medical research on fetal development. The best app for you depends on which features you value — weekly updates, symptom logging, contraction timing, meditation, or kick counting. Look for apps that cite medical sources, protect your privacy, and don't overwhelm you with ads.

Q: What features should a good pregnancy tracker have?

A good pregnancy tracker should include week-by-week developmental updates, a due date calculator, symptom tracking, milestone notifications, and educational content about each trimester. Bonus features like a contraction timer, baby kick counter, and meditation library add practical value during later pregnancy and labor.

A pregnancy tracker gives you a window into what's happening inside your body each week — from the first heartbeat to the final contractions. Here’s what to expect across all 40 weeks. Here’s what a good tracker includes. And here’s how to pick one that respects your privacy.

What Is a Pregnancy Tracker?

A pregnancy tracker is a tool that maps your pregnancy week by week. It tells you how far along you are, how big your baby is, what organs are developing, and which symptoms are typical at your stage. Most pregnancy trackers are mobile apps. Some trackers are web-based calendars. Some trackers are printed journals.

The idea is pretty simple. You enter your due date or the first day of your last menstrual period. The tracker then calculates your current gestational week. From there, it gives you weekly updates. It usually lists your baby’s approximate size (often compared to a fruit or vegetable). It also covers developmental milestones. And it flags common physical changes you might notice in your own body.

Pregnancy trackers aren’t diagnostic tools. They don't detect complications or replace the blood tests, ultrasounds, and physical exams your provider performs. What they do well is fill the gap between prenatal appointments. When your next visit is three weeks away and you're wondering whether that new ache is normal, a good tracker gives you context.

If you don't yet know your due date, start with a due date calculator — you'll need that number to set up any tracker accurately.

Week-by-Week Overview: What Happens Each Trimester

Forty weeks is a long time. Breaking pregnancy into trimesters usually makes it easier to wrap your head around it. It also makes it easier to track. Here’s what happens in each phase. And here’s what your tracker should be showing you.

First Trimester (Weeks 1–12)

This is when everything begins, even though you won't look or feel pregnant for most of it. Conception typically happens around week 2 or 3. By week 4, the fertilized egg implants in the uterine wall. It starts producing hCG, the hormone that turns a pregnancy test positive.

Week 6 brings the first heartbeat. The heart rate is fast, around 110 beats per minute. The fetal heart rate will speed up to 150–170 bpm before it gradually settles. By week 8, all major organ systems are forming: brain, heart, lungs, kidneys, and liver. The embryo is roughly the size of a raspberry.

By week 12, the baby (now called a fetus) has fingers and toes. By week 12, the fetus also has the beginnings of fingernails. The risk of miscarriage drops significantly after an ultrasound confirms a heartbeat. That’s why a lot of women wait until the end of the first trimester to share the news.

Common symptoms during this time include nausea (morning sickness affects up to 80% of pregnant women), fatigue, breast tenderness, frequent urination, and food aversions. Some women feel almost nothing. In most cases, neither one is a reason to panic.

Second Trimester (Weeks 13–26)

For many women, the second trimester is the most comfortable stretch of pregnancy. Nausea typically fades by week 14 or 15. And for a lot of us, energy starts to come back. The baby bump usually starts to show. Around this time, the pregnancy often starts to feel real in a really tangible way.

Between weeks 18 and 22, you’ll have the anatomy scan. It’s a detailed ultrasound that checks the baby’s organs, limbs, spine, and brain. This is often when parents find out the baby's sex, if they want to know.

Quickening is the first time you feel the baby move. Quickening usually happens between weeks 16 and 25. First-time mothers tend to notice it later, usually around week 20 to 22. It usually starts as little flutters, then it gradually turns into unmistakable kicks. Once you can feel consistent movement, your provider may recommend daily kick counting starting around week 28.

By the end of the second trimester, the baby weighs about 1.5 to 2 pounds. The lungs are still developing. The lungs aren't yet mature enough for independent breathing. The baby can hear sounds. The baby can respond to light. The baby has regular sleep-wake cycles.

Third Trimester (Weeks 27–40)

The final stretch. The baby gains weight rapidly, roughly half a pound per week. The uterus expands to accommodate a 6-to-9-pound newborn. Space gets tight, and you'll probably feel it.

By week 32, the baby's bones are hardening. The skull stays flexible for delivery. The lungs produce surfactant. Surfactant is needed for breathing outside the womb. By week 36, most babies have turned head-down to get ready for birth.

Common third-trimester symptoms include back pain, heartburn, shortness of breath, swollen ankles, Braxton Hicks contractions (practice contractions that don't progress into labor), trouble sleeping, and frequent urination (again). Your tracker should help you distinguish between early labor signs and normal late-pregnancy discomfort.

At 37 weeks, the baby is considered early term. Full term is 39 to 40 weeks. If you go past your due date, your provider will talk with you about monitoring and possible induction options.

Pregnancy tracker app showing week by week development milestones and symptoms

What a Good Pregnancy Tracker Includes

Not all pregnancy trackers are built the same. Some do little more than show a fruit comparison each week. Some trackers pack in so many features that they feel overwhelming. The best trackers strike a balance — enough depth to be genuinely useful, without turning pregnancy into a homework assignment.

Here's what to look for:

Week-by-week developmental updates. Clear, medically grounded descriptions of what's happening with your baby and your body at each stage.
Due date calculator. An accurate tool that accounts for cycle length, not just a standard 28-day assumption. See our due date calculator for details on how this works.
Symptom tracking. You can log what you're feeling, like nausea, headaches, energy levels, and mood, so you can share patterns with your provider.
Milestone notifications. It gives gentle reminders about upcoming appointments, screenings, and developmental markers, without stirring up extra anxiety.
Contraction timer. This tends to be especially helpful in the third trimester. A built-in contraction timer tracks duration and frequency so you know when to call your provider or head to the hospital.
Kick counter. From week 28 onward, counting fetal movements matters. A built-in counter makes it easier to keep track. It also saves your history.
Educational content matters, too. Look for reliable information on nutrition, exercise, labor prep, and postpartum recovery. Bonus if it includes hypnobirthing or meditation for mental preparation.
Privacy-first design. Your pregnancy data is sensitive. A tracker that stores information locally on your device can feel more private. It shouldn’t require an account. It also shouldn’t share your data with advertisers. Honestly, cloud-based alternatives don’t always give that same peace of mind.

Common Pregnancy Symptoms by Trimester

Symptoms vary widely between women and even between pregnancies for the same woman. That said, certain patterns are well-documented. Knowing what's normal at each stage helps you tell typical pregnancy discomfort from symptoms that need medical attention.

First Trimester Symptoms

Nausea and vomiting (peaks around weeks 8–10, often resolves by week 14)
Extreme fatigue and the need for extra sleep
Breast tenderness and swelling
Frequent urination as the uterus presses on the bladder
Food aversions or unusual cravings
Mood changes driven by hormonal shifts
Light spotting (implantation bleeding), which is usually harmless but worth mentioning to your provider

Second Trimester Symptoms

Round ligament pain — sharp or dull aches on the sides of the abdomen as the uterus stretches
Nasal congestion and nosebleeds (increased blood volume affects mucous membranes)
Visible baby bump and the need for maternity clothing
Skin changes including linea nigra (dark line on the abdomen) and the "pregnancy glow"
Baby's first movements (quickening)
Increased appetite as nausea subsides
Leg cramps, especially at night

Third Trimester Symptoms

Braxton Hicks contractions — irregular, painless tightening of the uterus
Back pain and pelvic pressure as the baby drops lower
Heartburn and acid reflux (the growing uterus pushes the stomach upward)
Shortness of breath as the diaphragm is compressed
Swollen feet and ankles (edema)
Difficulty sleeping due to discomfort and frequent bathroom trips
Nesting instinct — a sudden urge to organize and prepare the home

A pregnancy tracker should contextualize these symptoms within your current week. If your tracker says Braxton Hicks are common at week 34, that can be reassuring and may help you avoid an unnecessary ER visit. But if contractions become regular and painful, that's a different situation entirely — use a contraction timer to track the pattern and contact your provider.

Pregnancy Milestones and What to Expect

Certain weeks stand out across every pregnancy. These are the moments that feel like markers in a long journey — and the ones a good tracker should highlight for you.

Week 4: Positive pregnancy test. HCG levels rise enough for detection.
Week 6: First heartbeat visible on ultrasound. A powerful moment for most parents.
Week 8: All major organs are forming. The embryo is now about half an inch long.
Week 12: End of the first trimester. Miscarriage risk drops sharply. Many parents share the news.
Week 14: Morning sickness typically begins to ease. Energy starts returning.
Week 20: Anatomy scan. Halfway point. Baby's sex can often be identified.
Week 24: Viability milestone. With intensive neonatal care, babies born at this stage have a chance of survival. Outcomes still vary significantly.
Week 28: Start of the third trimester. Daily kick counting is often recommended from this point.
Week 36: Most babies turn head-down. Appointments become weekly.
Week 37: Early term. The baby's lungs are nearly mature.
Week 39–40: Full term. This is the optimal window for delivery in uncomplicated pregnancies.

Between those milestones, there are dozens of smaller developments. The baby's eyes open. Taste buds form. Hiccups start. A tracker that surfaces these details makes the waiting weeks feel less empty.

How Pregnancy App Tracks Your Pregnancy

Pregnancy App is a free pregnancy tracker available on iOS and Android. It combines weekly pregnancy updates with practical tools you'll use in all three trimesters. And honestly, you’ll probably use it the most during labor.

When you open the app, you type in your due date. From there, the app calculates your current week. It then shows content that matches your stage of pregnancy. But Pregnancy App isn't just a week-by-week calendar. It includes:

Contraction timer — tap to start, tap to stop. The app tracks duration, frequency, and intervals. It alerts you when your contraction pattern matches the 5-1-1 rule (contractions every 5 minutes, lasting 1 minute, for at least 1 hour).
Baby kick counter — log fetal movements with a single tap. The app tracks your daily counts and timestamps so you can identify changes in your baby's activity pattern.
Due date calculator — enter your LMP and cycle length for an adjusted estimate. You can track the countdown right in the app.
Hypnobirthing meditations — audio sessions designed for each trimester that use relaxation techniques based on research about the parasympathetic nervous system. Women who practice hypnobirthing often report reduced anxiety and more positive birth experiences.
Breathing exercises — specific breathing techniques for labor that you can practice daily and then use during actual contractions.
Pregnancy meditation library — guided pregnancy meditations for sleep, anxiety, bonding, and labor preparation.

The contraction timer and hypnobirthing audio work offline, so hospital WiFi (or lack of it) is never a problem. Over 200,000 mothers have used Pregnancy App. It has a 4.7-star rating across app stores.

Privacy and Your Pregnancy Data

Pregnancy data is personal. Your due date, symptoms, contraction history, and kick counts are sensitive health information. Not every app handles that kind of data as carefully as it should.

Some pregnancy tracker apps require you to create an account, verify your email, and agree to terms that allow data sharing with third-party advertisers or analytics providers. In 2023 and 2024, several major period and pregnancy tracking apps faced scrutiny for how they handled user data. That scrutiny increased after legal changes around reproductive health in the United States.

Pregnancy App takes a different approach. Tracking data is stored locally on your device. No account is required. No login. No email verification. The app does not collect personally identifiable health data, and no pregnancy information is shared with third parties. If you delete the app, the data goes with it.

Honestly, this matters more than most people realize. Before you type your due date, last period, or any symptom into a pregnancy tracker, read the app’s privacy policy. Ask these questions:

Does the app require an account or login?
Is my data stored on my device, or on the company’s servers?
Does the privacy policy say it shares data with "partners" or "third parties"?
Can you use the core features without sharing your name or email?

If the answers make you uncomfortable, find a different tracker. Your pregnancy data should belong to you.

Comparing Pregnancy Tracker Apps

There are dozens of pregnancy tracker apps available on iOS and Android. The big apps, Flo, What to Expect, The Bump, BabyCenter, Ovia, and Pregnancy App, all cover the basics. These apps include a due date countdown. The differences usually come down to extra features, privacy practices, and overall design.

Here are a few things to think about when you’re choosing one:

Feature depth. Do you want just a weekly update, or do you also need a contraction timer, kick counter, and meditation library? Some apps do one thing well. Others bundle everything together.
Privacy model. Apps funded by advertising tend to collect more data. Apps with subscription models may collect less, but not always. Read the privacy policy — not the marketing page.
Content tone. Some trackers lean hard on community forums. Those forums can also spike your anxiety. Others focus on curated content from medical writers. So pick the one that fits your temperament.
Offline functionality. If you want to use your tracker during labor — especially the contraction timer and breathing exercises — check whether the app works without internet access.
Ad experience. Free apps supported by ads can feel intrusive during vulnerable moments. Some show ads between contraction counts or during meditation playback. Others don't.

There isn't a single "best" pregnancy tracker app. The right app depends on how you like to take in information. Try two or three early in pregnancy, then stick with the one that fits you best.

TL;DR

A pregnancy tracker follows your pregnancy week by week — showing baby development, expected symptoms, and milestones at each stage.
The first trimester (weeks 1–12) covers implantation through organ formation. The second (weeks 13–26) brings the anatomy scan and first kicks. The third (weeks 27–40) is rapid weight gain and labor preparation.
A good tracker includes a due date calculator, symptom logging, contraction timer, kick counter, and educational content.
Privacy matters. Check whether the app stores data locally or on external servers, and whether it shares data with third parties.
Pregnancy App is a free pregnancy tracker on iOS and Android with a contraction timer, kick counter, due date calculator, and hypnobirthing meditations. Data stays on your device. No account required.

Limitations & Safety

A pregnancy tracker is an informational and wellness tool. It is not a medical device. It does not diagnose conditions, detect complications, or monitor fetal health. The developmental timelines presented in any tracker — including Pregnancy App — are based on population averages. Your baby may develop faster or slower than the weekly descriptions suggest. Both are usually normal.

Symptom information in a tracker is general. It can tell you that back pain is common in the third trimester, but it cannot tell you whether your specific back pain is muscular strain or a sign of preterm labor. That distinction requires clinical assessment.

Pregnancy trackers should supplement prenatal care, never replace it. Go to all your scheduled appointments. Follow your provider's recommendations for screenings, tests, and monitoring. If you experience severe pain, vaginal bleeding, fluid leakage, reduced fetal movement, vision changes, or a persistent headache, contact your healthcare provider immediately. Don’t wait for your tracker to tell you something is wrong. It can’t.

Pregnancy App isn’t affiliated with any hospital, clinic, or medical organization. The content in the app and on this page is written for informational purposes and does not constitute medical advice.

Frequently Asked Questions

What is a pregnancy tracker?

A pregnancy tracker is a tool, usually a mobile app, that follows your pregnancy from conception to birth. It shows your current week of pregnancy. It shows your baby's size and development. It lists expected symptoms. It flags upcoming milestones. It counts down to your due date. Most trackers update weekly with new information matched to your gestational age.

When should you start using a pregnancy tracker app?

You can start as soon as you get a positive pregnancy test, typically around week 4 or 5. If you start earlier, your tracking history will be more complete. Some women start after their first prenatal appointment when they have a confirmed due date from an ultrasound.

Are pregnancy tracker apps accurate?

Pregnancy trackers give general development timelines based on established medical research on fetal growth. In most cases, they’re accurate for broad milestones. That includes when organs form, when the baby can hear, and when the lungs mature. They cannot account for individual variation. Every pregnancy develops at a slightly different pace. So treat tracker info like a guide, not a diagnostic tool.

What pregnancy tracker app is the most accurate?

No single app is definitively the most accurate. Most reputable pregnancy trackers pull from the same medical research on fetal development. The best app for you depends on which features you value — weekly updates, symptom logging, contraction timing, meditation, or kick counting. Look for apps that cite medical sources, protect your privacy, and don't overwhelm you with ads.

Do pregnancy tracker apps share your data?

It depends on the app. Some pregnancy trackers collect personal health data. Some trackers share that data with third parties for advertising or analytics. Some pregnancy apps store your data locally on your device. Honestly, always read the privacy policy before you type in anything sensitive. Pregnancy App stores your tracking data on your device. You don't need an account or a login to use it.

Can a pregnancy tracker replace prenatal care?

No. A pregnancy tracker is an informational and wellness tool. A pregnancy tracker can't diagnose conditions. A pregnancy tracker can't detect complications. A pregnancy tracker can't replace the clinical assessments your doctor or midwife does at prenatal visits. Use the app to stay in the loop between appointments. But when it comes to medical decisions, always follow your healthcare provider's guidance.

What features should a good pregnancy tracker have?

A good pregnancy tracker should have week-by-week development updates. It should have a due date calculator. It should include symptom tracking. It should send milestone notifications. It should offer educational content about each trimester. Bonus features like a contraction timer, baby kick counter, and meditation library can be genuinely helpful in later pregnancy and during labor.

Is Pregnancy App free to use as a pregnancy tracker?

Yes. Pregnancy App is free to download on iOS and Android. The pregnancy tracker is available at no cost. The contraction timer is available at no cost. The kick counter is available at no cost. The due date calculator is available at no cost. Select meditations are available at no cost. Premium hypnobirthing audio content is available through an optional subscription. No account or login is required.