Can Morning Sickness Start Before You Get A Positive Pregnancy Test?

Detecting pregnancy seems like it would be a black-or-white, pregnant-or-not, binary thing, but that's not always the case. This is especially true if you don't happen to be trying to conceive, as you’re likely not monitoring every little hormonal change in your body. And even if you are actively trying for a baby, sometimes early pregnancy can go undetected. Given that, is it possible to have morning sickness before a positive test for pregnancy?

What is morning sickness?

Typically, morning sickness — which is notoriously incorrectly named, as it can occur at any time of day — subsides by the end of the first trimester. It’s estimated that a whopping 94% of pregnant people will experience some form of pregnancy nausea, according to a 2021 study in BMC Pregnancy and Childbirth. “Morning sickness typically occurs by six weeks of gestation,” Dr. Kecia Gaither, a double board-certified OB-GYN, maternal-fetal medicine specialist. “It's variable among women as to whether it occurs.”

For those who are actively trying to conceive, they’ll often find out from an at-home pregnancy test within the first four to six weeks of pregnancy. However, that diligent monitoring obviously isn’t the case for everyone. For all you need to know about whether or not you could experience morning sickness before a missed period, read on.

Can you have morning sickness before a positive pregnancy test?

If you’re not trying for a baby, you may be surprised to notice nausea, tender breasts, and hormonal skin changes before you realize your period is late. Contraceptive use and irregular menstrual cycles can interfere with the traditional timeline for tracking your menstrual cycle. And some people who ovulate early, especially those with a longer than average menstrual cycle, can start feeling symptomatic earlier than they would likely be taking a pregnancy test, according to a 2015 study published in the Cochrane Database of Systematic Reviews. “It is very common to start feeling pregnant and have a sense of being pregnant before you can test positive via a test,” certified nurse midwife Chana Meir tells Romper. She chalks this up to a mother's intuition more than anything else.

However, a new study shows that it might be more than just a feeling. Morning sickness was historically believed to be linked to hCG, the hormone detected by pregnancy tests, which can show up in your urine around 12 to 15 days after ovulation. With that thinking, experts once found it unlikely that morning sickness could start before a positive pregnancy test. However, the aforementioned 2021 study in BMC Pregnancy and Childbirth, conducted by researchers from the University of Warwick in England, discovered that some people started feeling early morning sickness eight to 10 days after ovulation.

The study, which measured the onset of symptoms from a person’s date of ovulation rather than the last menstrual period, demonstrated that pregnancy symptoms can start earlier than previously thought. Given that logic, it’s certainly possible that someone would experience nausea and vomiting before getting a positive pregnancy test or missing a period.

Other reasons for nausea before a missed period

There are several reasons someone might feel nausea before missing a period, including early pregnancy. But just because you wake up feeling unexpectedly queasy doesn’t automatically mean you’re pregnant.

“Nausea before a missed period may be due to gastritis,” Gaither notes — inflammation of the stomach lining. This can be caused by anything from injury, infection, alcohol consumption, or the regular use of pain pills. Or you could simply be feeling ill from catching a virus or food poisoning.

Even the reasons for missing a period don’t always point to pregnancy. Certain forms of birth control can influence irregular menstruation, as can stress, diet, illness, weight fluctuation, vigorous exercise, and even travel.

If you do miss a period, notice some nausea, and are concerned about whether or not you are pregnant regardless of an at-home test, the best bet is to visit your health care provider. Your doctor can offer you bloodwork panels, which will measure all sorts of hormonal levels in your body, and they can tell you all you need to know about why you feel poorly — be it pregnancy or just some dodgy diner food that’s taken a nasty hold on you.

Studies referenced:

Gadsby, R., Ivanova, D., Trevelyan, E. et al. The onset of nausea and vomiting of pregnancy: a prospective cohort study. BMC Pregnancy Childbirth 21, 10 (2021). https://doi.org/10.1186/s12884-020-03478-7

Matthews, A., Dowswell, T., Haas, D. M., Doyle, M., & O'Mathúna, D. P. (2015). Interventions for nausea and vomiting in early pregnancy. The Cochrane database of systematic reviews, (9), CD007575. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD007575.pub3/full

Experts:

Dr. Kecia Gaither, M.D., MPH, FACOG, double board-certified OB/GYN and Maternal Fetal Medicine specialist and Director of Perinatal Services at NYC Health + Hospitals in the Bronx

Chana Meir, certified nurse midwife