Could you be pregnant? Look out for these early pregnancy symptoms. Some of these first signs of pregnancy can show up before you even miss your period.

Perhaps you've ditched birth control, started tracking your cycle and have been actively trying to conceive. You may be wondering: Are the symptoms you’re experiencing just PMS, or could I be pregnant?

Before you even take a home pregnancy test, you may get a heads-up in the form of some early pregnancy symptoms, including smell sensitivity, breast changes and fatigue. But because many of these early signs of pregnancy will be similar to symptoms you have right before you get your period, it can be hard to tell the difference.

While the only way to know for sure that you've got a baby on board is by peeing on a stick (then getting those results confirmed by a doctor), these early symptoms — some of which can occur before a missed period — may provide clues that you’re expecting.

When do pregnancy symptoms start?

First, it's important to note that pregnancy symptoms can crop up at different times in different people. And while some women experience every pregnancy symptom possible, others experience very few (if any) of these signs until many weeks into their pregnancies, if at all.

So with that said, here's average pregnancy symptoms timeline, based on a typical 28-day menstrual cycle:

• About 14 days after your last period: Conception
• 17 or more days after your last period: Sensitivity to smell, tender breasts, fatigue, raised basal body temperature may begin
• 20 to 26 days after your last period: Implantation bleeding, thicker cervical mucus may occur
• 28 to 35 days after your last period: Frequent urination and mood swings may begin; missed period
• 35 or more days after your last period: Other pregnancy symptoms may begin at any point during the first trimester.

Early signs of pregnancy (Before a missed period: Pregnancy weeks 2-4)1. Raised basal body temperature

If you've been using a special basal body thermometer to track your first morning temperature, you might notice that it rises around 1 degree when you conceive and stays elevated throughout your pregnancy.