Deciphering whether you’re experiencing pregnancy symptoms can feel confusing and overwhelming. Is your stomach upset from something you ate, or could it be morning sickness? Are you feeling unusually tired, or just coming down with something? With so many overlapping possibilities, it’s easy to second-guess what your body is telling you.

While no two pregnancies are exactly the same, even for the same woman, certain symptoms may point to pregnancy. Below, we outline what to watch for before a missed period, how symptoms can change week by week, and when testing can give you clearer answers.

Pregnancy Symptoms: What to Watch For

There’s no specific formula for the timing of early pregnancy symptoms, as it varies from person to person and pregnancy to pregnancy. Often, many moms-to-be do not notice changes in their body until several weeks after conception. However, there are exceptions. You may notice a difference in your body within as little as one week. For instance, sensitivity to smell and tender breasts may appear before you miss your period or within days of conception. However, other indicators, such as frequent urination, may appear weeks later. Here is a breakdown of when many women notice specific symptoms.

Pregnancy Symptoms Before Missed Period

It is a common misconception to believe that symptoms may only appear after you’ve missed your menstrual period. Not so! The human body works miraculously and offers us subtle hints we’ve conceived. We just have to pay closer attention to it.

Here are some early symptoms that may appear before a missed period:¹

• Breast changes
• Cramping
• Darkened areolas
• Food cravings or aversions
• Heightened sense of smell
• Headaches or lightheadedness
• Light spotting
• Nausea
• Raised basal body temperature
• Tiredness

If you want a deeper explanation of how these symptoms may show up early, you can read more about the early signs of pregnancy.

Pregnancy Symptoms: Week by Week

As stated above, many women may not notice any symptoms later in their pregnancy. Here is a general weekly breakdown of when women typically experience symptoms in early pregnancy.

Pregnancy Symptoms Week One

Although it may seem odd, healthcare professionals determine your first week of pregnancy based on the first day of your last menstrual period (or the LMP dating method).² This means that at week one, your period has just begun. At this point, you may experience the usual menstrual cycle pains, such as fatigue, abdominal cramps, swollen breasts, and lower back pain.

Pregnancy Symptoms Week Two

While this timing may already feel confusing, we’re sorry to add another layer. At week two, you’re now ovulating. You may experience common symptoms of this stage, such as light spotting, an increased libido, changes in your cervix and cervical mucus, and pelvic aches.³ Due to hormonal changes, you may also notice a heightened sense of smell.

Related: Ovulation Symptoms and Signs

Pregnancy Symptoms Week Three

Once you’ve journeyed into week three, the pregnancy magic officially launches. At this stage, not only will your ovaries have released an egg 14 days after your LMP, but the egg will also travel through the fallopian tubes to be fertilized.⁴ Remember: sperm can live inside your body for up to five days!⁹

You may not even suspect that you’ve conceived during this time, so symptoms will likely kick in a little after week three. Your initial indicator that you have a baby on board is a missed menstrual cycle (although this may not happen until week four).⁵ But you may also notice spotting, which is not to be confused with your period. This is known as implantation bleeding and occurs when your fertilized egg attaches to the uterine lining. Additional symptoms can include fatigue, changes in your breasts, mild cramping, belly bloat or gas, and a metallic taste in the mouth.

Common Pregnancy Symptoms

Following the third week after your missed period, there are several telltale signs of early pregnancy that many women may experience.⁶ It’s important to note that not everyone will have the same symptoms. Some may have almost all key symptoms, whereas others may experience only one or two. If you’re unsure of what you’re feeling, here are several early pregnancy symptoms that may indicate you’re expecting:

Fatigue

Most women who’ve confirmed with their doctor that they’re pregnant report feeling frequent episodes of fatigue. Not only do they nap when they usually wouldn’t, but they also seem unable to shake off the sleepiness, regardless of how much sleep they get or how hydrated they are. The reason? As levels of progesterone (a hormone emitted from the ovaries) rise, women feel more exhausted than usual.

Related: Tips for Battling Pregnancy Fatigue

Increased Urination

You may find that you’re urinating more than usual if you’re expecting. Since blood volume in your body increases during gestation, your kidneys must filter your blood and remove the extra waste. This added waste is processed as a liquid in your bladder, leaving you to take frequent trips to the bathroom.

Missed Period

A missed period is the most typical and obvious symptom that leads women to take a pregnancy test. You might be pregnant if it has been a week or longer and your expected menstrual cycle hasn’t begun. However, remember that this symptom is not always 100 percent accurate. Some individuals may have an irregular menstrual cycle, feel stressed, or have hormonal problems that result in a delayed or missed period.

Nausea

Ah, the infamous morning sickness. As the second most notorious early pregnancy symptom, nausea can strike a woman morning, day, and night despite its well-known moniker. About 7 in 10 pregnant women experience morning sickness throughout the first trimester, beginning around six weeks of gestation.¹⁰

While the reason for morning sickness is not entirely known, studies have shown that nausea and vomiting in the first three months of pregnancy may be due to increased hormones in the body from pregnancy.¹¹

Research has also revealed that this may occur due to human chorionic gonadotropin (HCG)—a hormone produced by the placenta soon after the fertilized egg attaches to the uterine lining. Those who experience severe morning sickness (hyperemesis gravidarum) have higher HCG levels than other pregnant women.¹²

Related: Ways To Relieve Morning Sickness

Tender or Swollen Breasts

Women may feel these symptoms early in their pregnancy, from swollen, sore, enlarged, or tender breasts due to increased pregnancy hormones. The areola (the area around the nipples) may also darken.

Keep in mind that while these signals may be informing you that you may be pregnant, the only way to positively confirm your pregnancy is to take a home pregnancy test and visit your physician to perform an ultrasound.

Related: What Are They Looking for at Your 8-Week Ultrasound?

Twin Pregnancy Symptoms

In the beginning, it can be challenging enough to determine if you’re pregnant with one child, but when you’re expecting two or more, your body will provide some clues. Some early indicators include severe morning sickness (as if morning sickness isn’t bad enough!), rapid weight gain, and extremely tender breasts.⁷ You may also notice extreme fatigue, a greater appetite, or begin showing sooner. However, the best method to confirm a twin pregnancy is to visit your physician’s office for an ultrasound.

Related: Signs You Might Be Having Twins or Multiples

PMS Symptoms vs. Pregnancy Symptoms

You may have recognized that some of the early signs of pregnancy seem very closely related to PMS–and you’re not wrong. The overlap between symptoms can be confusing and stir up a whirlwind of emotions.⁸ To help you decide which symptoms correspond with which result, we’ve created a brief table to offer some guidance:

Determining whether you’re pregnant can be both exciting and nerve-wracking. If you’re experiencing symptoms and feel unsure, the most reliable next step is taking a home pregnancy test or visiting your doctor. They can confirm pregnancy through testing or ultrasound and help guide you through what comes next.