First trimester symptoms week by week, and what's normal

The first trimester can feel like the longest, strangest, most secret stretch of your whole pregnancy. Your body is doing something enormous, yet on the outside almost nothing shows. One day you feel completely fine, the next you're flattened by exhaustion or hit with a wave of nausea at the smell of your own coffee. If you've found yourself searching "is this normal in early pregnancy?" at 2 a.m., you are in very good company, and this guide is for you.

Below we walk through the first trimester week by week, from the moment you conceive through the end of week 13. For each stretch you'll find what's happening inside, the early pregnancy symptoms most people notice, and a calm reminder of what's normal. Pregnancy weeks are counted from the first day of your last period, so the first couple of "weeks" happen before you're even pregnant, which is one of pregnancy's odder facts and a common source of confusion.

Weeks 1-4: before the missed period

For the first two weeks you aren't pregnant yet in the technical sense, your body is preparing to release an egg. Conception typically happens around week 2 to 3, and then the fertilized egg travels to the uterus and implants in the lining toward the end of week 4. This is when the pregnancy hormone hCG starts to rise, which is exactly what a positive test detects.

Most people feel nothing at all this early, but a few notice subtle signals:

• Implantation spotting, light pink or brown discharge, sometimes mistaken for an early, very light period.
• Mild cramping, a little like period cramps, as the embryo implants.
• Tender, heavier-feeling breasts as hormones shift.
• A missed period, often the very first clue, right at the end of week 4.

A home pregnancy test is usually accurate from the day of your missed period. If you test too early and get a negative but your period still doesn't arrive, wait a few days and test again, hCG roughly doubles every two to three days in early pregnancy.

Weeks 5-6: the symptoms often begin

This is when many people start to truly feel pregnant. By week 5 your baby is about the size of a sesame seed, and the heart is beginning to form. Hormone levels are climbing fast, and that's behind most of what you'll notice now.

Common symptoms in weeks 5 and 6 include:

• Nausea (so-called "morning sickness" that can strike at any hour), often starting around now and sometimes with vomiting.
• Bone-deep fatigue, the kind where you could nap at your desk, driven by rising progesterone.
• Sore, swollen breasts and darkening of the area around the nipples.
• Frequent urination as blood flow to your kidneys increases.
• Heightened sense of smell and new food aversions, a previously loved meal can suddenly turn your stomach.
• Mood swings, weepy one minute, irritable the next, all completely normal.

This is also the typical window for your first prenatal appointment to be booked. If you haven't contacted a doctor or midwife yet, now is a good time, partly so you can start (or continue) a prenatal vitamin with folic acid, which supports your baby's developing spine.

Weeks 7-8: nausea and fatigue peak

By week 8 your baby is about the size of a raspberry and has grown astonishingly fast, tiny limbs are forming and the heart is beating steadily. For many people, weeks 7 and 8 are the most physically demanding of the entire first trimester.

What's normal right now:

• Nausea at its strongest, sometimes all day. Eating small, frequent, bland snacks (crackers, toast, ginger) and staying hydrated can take the edge off.
• Overwhelming tiredness, listen to your body and rest when you can.
• Excess saliva, bloating, gas, and mild constipation, all thanks to pregnancy hormones slowing digestion.
• More visible veins and occasional light-headedness as your blood volume expands.

Weeks 9-10: still hormonal, often still queasy

Around week 10 your baby officially graduates from embryo to fetus and is roughly the size of a strawberry, with tiny fingers, toes, and the beginnings of nails. Your uterus is now about the size of a grapefruit, though a bump usually isn't visible yet.

Symptoms in weeks 9 and 10 are largely a continuation of earlier weeks, nausea, fatigue, tender breasts, and emotional ups and downs, but you may also notice:

• Visible veins across your breasts and belly.
• A little weight change in either direction, gaining a pound or two, or losing slightly if nausea is heavy, both can be normal.
• Round ligament twinges, mild pulling sensations low in the abdomen as everything stretches.
• Continuing food cravings and aversions.

Many people have their first ultrasound and may hear the heartbeat around this time, which can be an enormously reassuring milestone after weeks of symptoms but no visible proof.

Want to see exactly what's happening week by week from here to your due date? Our complete pregnancy week-by-week guide walks you through all three trimesters, from baby's size to what to expect at each appointment.

Weeks 11-13: the corner begins to turn

Welcome to the home stretch of the first trimester. By week 12 your baby is about the size of a lime and is fully formed in miniature, all the major organs are in place and now simply need to grow. This is a genuine turning point: for many people, the worst of the nausea and fatigue starts to ease as hormone levels stabilize and the placenta takes over hormone production.

What you might notice in weeks 11 to 13:

• Nausea beginning to lift for many (though not all, some sail past it into the second trimester, and that's normal too).
• A slowly returning appetite and a little more energy.
• The very first hint of a bump, especially if this isn't your first pregnancy.
• Visible veins, mild headaches, and occasional dizziness as blood volume keeps rising.
• A noticeable drop in the constant need to pee, as the uterus rises out of the pelvis.

The end of week 13 marks the close of the first trimester, and statistically the risk of miscarriage drops significantly once you reach this point. It's the moment many people feel ready to share their news.

When to call your doctor or midwife

Most first trimester symptoms, however unpleasant, are completely normal. But some signs always deserve a prompt call to your healthcare provider, not to alarm you, but so you're never left wondering. Contact your doctor or midwife if you experience:

• Vaginal bleeding that's heavier than light spotting, especially with cramping or clots.
• Severe or one-sided abdominal pain, particularly with shoulder-tip pain or faintness, which can be a sign of ectopic pregnancy and needs urgent care.
• Severe, persistent vomiting where you can't keep fluids down (possible hyperemesis gravidarum).
• Fever, chills, or pain or burning when you pee, which may point to an infection.
• Sudden disappearance of pregnancy symptoms paired with bleeding or pain (on its own, fading symptoms late in the trimester is often just normal).
• Dizziness or fainting that's severe or recurring.

Trust your instincts. If something simply feels wrong, you are never being "dramatic" by calling, that's exactly what your care team is there for. In an emergency, such as heavy bleeding or severe pain, seek urgent medical help right away.

The bottom line on early pregnancy symptoms

The first trimester asks a lot of you, often before you can even tell anyone what you're going through. Nausea, exhaustion, sore breasts, mood swings, and a hyperactive sense of smell are all normal companions of these early weeks, and they tend to ease as you move into the second trimester. A quieter pregnancy with few symptoms is just as normal as a loud one. Eat what you can keep down, rest without guilt, stay hydrated, take your prenatal vitamin, and keep your prenatal appointments. And whenever a symptom worries you, reach out to your doctor or midwife, peace of mind is part of good care.