Early signs of pregnancy: 8 symptoms to look out for

It's easy to scrutinize every twinge and odd sensation when you think you might be pregnant. If you don’t have access to a pregnancy test or if it’s too early to take one, you might be wondering if there are any early pregnancy signs you can watch out for. 

Aside from a missed period, early signs of pregnancy include—but are not limited to—sore breasts, bloating, fatigue, and mood swings. It’s possible to experience these symptoms shortly after conception, but you may not experience any pregnancy symptoms until after you get a positive pregnancy test. 

While testing is always more accurate than an assumption based on a handful of symptoms, it’s still useful to understand why and how early pregnancy symptoms occur. 

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Progesterone and human chorionic gonadotropin (hCG) are the two hormones to blame for those somewhat inconvenient early pregnancy symptoms. As these hormones start to rise, your symptoms become more pronounced. But when do symptoms “officially” start?

In the first few days following implantation—the fourth week of pregnancy—you may not have any symptoms at all, but research shows that by week five, they may start kicking in. A study of pregnant women found that around half experienced pregnancy symptoms as early as weeks five to six of pregnancy, and by week eight, 90% of women had symptoms (Sayle, 2002).

While symptoms look different later in pregnancy (when your uterus starts to expand and other hormones help relax your pelvis for childbirth), the most common symptoms at the start of your pregnancy include a missed period, mild cramping, nausea, constipation, fatigue, frequent urination, breast changes, and mood swings (Kapley, 2021).  

1. Missed period 

Often, the first sign of pregnancy is a missed period. Unfortunately, if your period is irregular or you don’t track your period, you may not be able to identify whether or not you missed your period (Bastian, 2020). 

Although missing your period is one of the earliest signs of pregnancy, some pregnant people experience light bleeding during the first weeks of pregnancy, which can be mistaken for a light period. If you are pregnant and experience bleeding, let your healthcare provider know. In some cases, bleeding can indicate pregnancy loss (Sapra, 2016).

2. Mild cramping 

As your uterus changes and grows, you may experience mild cramping, which can be similar to your typical menstrual cramps. Although mild cramping may occur early in pregnancy, it can also signify pregnancy loss, especially when it occurs alongside vaginal bleeding (Sapra, 2016). 

3. Nausea

Nausea, dry heaving, and vomiting are all common symptoms of pregnancy. Nausea is most common in the first trimester—between weeks 6–12—and is thought to be the result of rising hCG levels. 

Approximately 50-80% of pregnant people will experience nausea, and about 50% will have episodes of vomiting or dry heaving. Although it’s commonly called “morning sickness,” nausea can happen at any time of day. Nausea can also make you more sensitive to certain smells increasing the likelihood of food aversions. The good news is nausea typically lessens in the second trimester (Matthews, 2015).

4. Constipation

Following nausea, constipation is the second most common side effect of pregnancy, with up to 40% of pregnant people experiencing it. 

It can occur at any point during pregnancy, including the first trimester, and it occurs because hormonal changes associated with pregnancy lengthen the amount of time it takes for food to pass through your colon. Constipation in later trimesters may be more mechanical, caused by the uterus taking up more space within the pelvis (Cullen, 2007). 

5. Fatigue

Constantly feeling tired can be another early sign of pregnancy. Fatigue tends to be its worst in the first trimester. Fortunately, you'll get a reprieve in the second trimester, but fatigue tends to pop back up in the third trimester due to the other symptoms of pregnancy that can make it hard to get a good night's sleep (Bastian, 2020). 

6. Frequent urination 

You may find yourself running to the bathroom as your uterus expands to accommodate a growing baby. In the first few weeks, your uterus is still on the small side; however, you may still find yourself peeing more than usual (Bastian, 2020). 

7. Breast changes

Early in pregnancy, you may notice your breasts feel fuller or tender. While tender breasts and soreness can be a sign of pregnancy, these are also common PMS symptoms. Later in pregnancy, you may notice more visible changes, such as your areolas darkening and the veins under your skin becoming more prominent (Bastian, 2020). 

8. Mood swings 

As your hormones fluctuate, you may find your mood fluctuating, too. Some pregnant women even develop depression during pregnancy (Rubertsson, 2014). While some of this is likely due to hormones, research suggests that those who experience physical symptoms, like nausea, have a higher likelihood of anxiety and depression (Ertmann, 2019). 

Even if you experience the symptoms above, that doesn’t mean you’re pregnant. Many of the early signs of pregnancy—sore breasts, bloating, fatigue, and mood swings—are similar to premenstrual syndrome or PMS, which occurs around the same time you may start to get a positive pregnancy test. 

So, if you think you might be pregnant, it’s best to test and confirm your hunch since these symptoms aren’t a reliable sign of pregnancy. Depending on the sensitivity of your test, hCG is often detectable within days of implantation.

If you aren't sure how far along you are, reach out to your ob-gyn. They can provide some insight based on ultrasounds, blood tests, and the first day of your last period (Anderson, 2022).

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

February 01, 2022

Written by

Jordan Davidson

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.