Is it possible to be pregnant and not know it?

Is it truly possible to not realize you’re pregnant until labor begins? Whether you’ve had a child yourself or know someone who gave birth, this phenomenon probably sounds wild. And yet, it does happen. 

Most women who have been pregnant can't even imagine not noticing it. Those who gained 50 pounds, hobbled on swollen ankles, or threw up for weeks find it hard to believe that a symptom-free pregnancy could happen. At the very least, wouldn’t you spot a missing period? But the fact is, with a cryptic pregnancy, you don’t realize your body is changing or you don’t experience some of those tell-tale signs.

Here’s the scoop on cryptic pregnancies, including how common they are, and how it’s possible to be expecting but not realize it.

What is a cryptic pregnancy? 

Also known as a stealth pregnancy or denied pregnancy, a cryptic pregnancy occurs when a woman doesn’t realize she’s carrying a baby. In fact, it may not become obvious until the pain of labor begins and the baby is soon to arrive. With a cryptic pregnancy, many of the common symptoms a woman tends to notice aren’t present or, if symptoms do show up, (pelvic pain, missed periods), they’re mistaken for something else.

Interestingly enough, cryptic pregnancies aren't rare. About 1 in 475 women don’t realize they’re pregnant until week 20 (most women learn they’re pregnant between weeks four and 12), according to the National Institutes of Health. And about 1 in 2,500 women are in the dark, so to speak, until they deliver. 

What causes a cryptic pregnancy?

A cryptic pregnancy is no different than any other pregnancy except for the fact that there may not be symptoms and the expecting mother doesn't know about it. Cryptic pregnancies are more common in women who:

• Have conditions that cause irregular or skipped periods, such as polycystic ovarian syndrome (PCOS) or perimenopause

• Are obese (a growing belly may not be as obvious)

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• Are very athletic, with low body fat (many of these women don't have regular periods and may have lower levels of some hormones that cause pregnancy symptoms)

• Get pregnant soon after giving birth (these women may not be expecting a period yet and attribute any weight gain to the previous pregnancy)

Some women have cryptic pregnancies because of serious mental health issues, such as bipolar disorder or schizophrenia. If they have pregnancy symptoms, they may think they’re related to their mental illness rather than a pregnancy. 

Women without serious mental health issues may experience enough stress and conflict surrounding the idea of being pregnant that they deny the pregnancy. Most women with cryptic pregnancies, however, don't have mental health issues.

Does a cryptic pregnancy really have no symptoms?

Cryptic pregnancy symptoms might be the same as other pregnancy symptoms (nausea and tiredness, for example). But some women don't have any pregnancy symptoms, or they have symptoms that are very mild. For some women, labor pains are the first symptom of pregnancy.

How could a woman not know she's pregnant?

If you've been pregnant and had those hallmark symptoms such as morning sickness, bloating, and mood swings, you may find it confusing that others might not have standout symptoms during pregnancy – but it happens. A woman might not know she's pregnant for a number of reasons. For example, she might:

• Not have typical pregnancy symptoms, or have mild symptoms due to low levels of pregnancy hormones

• Attribute her pregnancy symptoms to something else (morning sickness might seem like a stomach bug or indigestion, and fatigue could be chalked up to lack of sleep)

• Have had a negative pregnancy test

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• Typically have irregular periods

• Be using birth control and might think it's impossible to be pregnant

• Think that she has infertility issues

• Be breastfeeding and think she can't get pregnant

And how do you explain the baby's fetal movement? Some women attribute it to gas, an upset stomach, or indigestion. Later in pregnancy, when movements are more dramatic and visible, denial is often a factor.

Can you be pregnant and get a negative pregnancy test?

Yes. Some women take a pregnancy test that turns up negative – even though they’re pregnant! Here are some reasons why you might have a false negative result: 

• You take the test too early. The best time to take a home pregnancy test is a few days after you miss your period. If you take it too early, the test won't be able to detect the increase in hCG (human Chorionic Gonadotropin) in your body. If you get a negative result, it's best to repeat the test a week later.

• You don't follow the directions carefully. Pregnancy test mistakes could give you a false negative result. Follow the package directions for timing, check the date on the package to make sure the pregnancy test isn't expired, and go through each step listed in the instructions to make sure you get the most accurate results.

• Your urine is very diluted. If you think you're pregnant and your urine is very diluted (it will appear clear like water), repeat the test again first thing in the morning when your urine  is more concentrated.

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If you have pregnancy symptoms after a negative home pregnancy test, call your provider. They may recommend you come in for a blood pregnancy test. 

Is a cryptic pregnancy dangerous?

Yes, a cryptic pregnancy can be dangerous: If you don't know you're pregnant, you're not going to seek out timely prenatal care. Getting good, regular care is important for a healthy pregnancy because your doctor or midwife will monitor how both you and your baby are doing and watch for complications. 

For example, preeclampsia can be very dangerous and often has no warning symptoms, but it can be picked up during prenatal visits with a simple blood pressure check. Also, babies who are born without prenatal care have a higher risk of being born premature or with a low birth weight. 

Other reasons a cryptic pregnancy can be dangerous include: 

• You may not take prenatal vitamins. Not realizing you're pregnant, you probably won’t take prenatal vitamins, which are important for your baby’s growth and development.

• You may consume alcohol. If you're unaware of your pregnancy, you may not abstain from things like alcohol, marijuana, high amounts of caffeine, or smoking. 

• You may not be prepared for labor and delivery. If you don't know you're pregnant, you'll likely be unprepared for labor – and you run the risk of having an unattended labor. 

• It may be harder to tell how your baby is doing. If your providers don't know your baby's gestational age, it may be more difficult for them to figure out how your baby’s doing once they’re born. After the birth, providers will do an Apgar test to assess your baby's size and condition. 

Cryptic pregnancies can also cause a lot of mental distress. Finding out you're many months into a pregnancy – or hours into labor – without knowing you were even pregnant can greatly affect your experience of pregnancy, labor, and delivery, as well as your relationship with your baby. 

If you do find out you're pregnant unexpectedly, set up an appointment with a provider as soon as possible, and lean on your friends, family, and moms in the BabyCenter Community for support.