PMS vs. Pregnancy Symptoms: Can You Tell the Difference?

When you’re trying to get pregnant, that two-week window between ovulation and a potential positive pregnancy test — or your period — can be nerve-wracking. Every month, you may wonder if this month is going to be the month — or just your time of the month again.

Unfortunately, the early signs of pregnancy and PMS are very similar, which can make it hard to tell what’s causing those sore boobs and strange food cravings.

Can you tell the difference between PMS and pregnancy?

Unfortunately, no. The only way to know for sure that you’re pregnant is to take a pregnancy test.

The good news is you don’t have to wait too long to find out: Home pregnancy tests are accurate enough now to pick up 90 percent of pregnancies the day of your expected period. (While some test manufacturers claim they can give you results as early as four or five days before your expected period, they’re only accurate about 60 percent of the time, which means if your result is negative, you should wait and retest to see if it’s the real deal.)

These home pregnancy tests all work by measuring levels of human chorionic gonadotropin (hCG) — a pregnancy-specific hormone — in your pee. Although some hCG is found in your urine as early as a week after conception, it’s usually not enough to register on a home pregnancy test. (If your period is irregular, wait the number of days equal to the longest cycle you’ve had in the last six months — and then test.)

Any positive test should be followed up by a call to your doctor, who can advise on next steps. 

Symptoms of PMS vs. symptoms of pregnancy

The second half of your menstrual cycle is known as the luteal phase, when your body produces more progesterone, a hormone key sustaining an early pregnancy. These levels peak about a week after ovulation, even if you don’t become pregnant.

High levels of this hormone can cause both physical and emotional changes, producing similar symptoms whether you’re in early pregnancy or right about to have a period. These include: Trusted SourceUpToDatePremenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD) (Beyond the Basics)See All Sources ^[1]

• Breast tenderness
• Bloating
• Food cravings
• Fatigue
• Moodiness
• Constipation
• Increased nipple sensitivity
• Headaches and muscle aches

But there are also specific symptoms that tend to indicate pregnancy, rather than PMS. Look for: Trusted SourceMayo ClinicSymptoms of Pregnancy: What Happens FirstSee All Sources ^[2]

• Changes in your areolas. Breast changes caused by pregnancy hormones such as tenderness or sensitivity tend to stick around rather than disappear shortly before the arrival of your period. Another tell-tale sign: Your areolas — the circles around your nipples — darken in color and increase in diameter. You may also see an enlargement in the tiny bumps normally on your areola so that they resemble goosebumps. These bumps (called Montgomery glands) produce oils to lubricate your nipples and areolas in prep for eventual nursing.
• Implantation bleeding. Another sign that you might be pregnant is spotting that shows up anywhere from a few days to a week before the day you normally get your period. This is known as implantation bleeding, and around 20 to 30 percent of newly expectant moms experience it when the embryo burrows into the uterine wall. Implantation bleeding is usually much lighter than a period, and can last anywhere from a few hours to a few days. Unlike your period, implantation bleeding isn’t red: It’s usually pale to medium pink or light brown in color — sometimes even resembling pink-tinged mucus.
• Smell sensitivity. Some newly pregnant women report that their sniffer’s suddenly more sensitive, which is due to the increasing amount of estrogen coursing through your body during early pregnancy. A heightened sense of smell can appear in the first trimester.

When to see a doctor

Even if you don’t have a positive pregnancy test and your period runs more than a week or two late, you should check in with your doctor, who may want you to come in for an appointment. Your OB/GYN can run a blood test to check for pregnancy, as well as other blood tests to look for hormone abnormalities such as a thyroid disorder that could mess up your menstrual cycle.

And remember, you can have every single pregnancy symptom on the book and not be pregnant, or virtually no symptoms and have successfully conceived. That’s why it's so important to wait to test until the day of your expected period — and follow up with your doctor if youre uncertain about results.