Can You Be Pregnant and Not Know It?

Reviewed by Dan Brennan, MD on March 31, 2022

You’ve probably heard a story about it at least once: a woman who didn’t know they were pregnant until they went into labor. Your first thought? How is it possible to not know you’re carrying a baby?

It’s not out of the question, says Michael Cackovic, MD, an OB/GYN at The Ohio State University Wexner Medical Center. “There are women who don’t have routine sex, don’t have routine periods, and don’t regularly see a doctor,” he says. Under those circumstances, it’s possible you could not realize you’re pregnant.

Other women have mental health problems that keep them from recognizing or accepting that they’re going to have a baby.

A few studies have estimated that one in 400 or 500 women are 20 weeks, or about 5 months, into their pregnancy before they realize they are pregnant. 

One in 2,500 women make it all the way to labor before they understand they’re going to have a baby. That’s about three times more common than a woman’s chance of having triplets.

How It Happens

A number of things could keep a woman from noticing the changes in their body:

Fear or stress. The thought of becoming a mother is so stressful for some women that they go into deep denial -- so deep that they don’t know they’re pregnant. “Denial is a very powerful defense mechanism, making it possible to talk yourself out of every symptom you may have. The movement in your abdomen is ‘just gas,’ for instance,” Cackovic says.

For example, a teenager may deny or ignore a pregnancy because they don’t want their parents to know they have had sex. A married woman may do the same because they got pregnant by someone other than their partner. Some women may have a denied pregnancy because of a mental health problem, like bipolar disorder or schizophrenia.

No symptoms. For some women, the physical tip-offs of pregnancy, like weight gain, morning sickness, heartburn, or fatigue, don’t happen. Or they’re so mild that a woman just doesn’t notice them. Depending on their body type, “it’s reasonable for a woman to make it to 30 weeks without looking pregnant,” Cackovic says.

Weight changes. If a woman is overweight or their size often goes up and down, they might not notice the extra baby weight. If they’re obese, Cackovic says, they may not “have the physical feelings of being pregnant” that non-obese women feel.

Period problems. A woman can have irregular periods because of stress, some medications (like birth control pills or drugs for epilepsy), obesity, or health problems like polycystic ovary syndrome (PCOS), uncontrolled diabetes, or an eating disorder. So when their period is a no-show, their first thought may not be pregnancy.

They can’t feel the baby move. Usually a mom-to-be will start to feel their baby kicking or rolling between 18 to 20 weeks of pregnancy. But if the placenta happens to be in the front of their uterus, they may not feel those movements, Cackovic says.

Research suggests a well-adjusted woman can have a denied pregnancy and still go on to be a good mother, especially if they’re able to come to grips with the fact that they’re going to have a baby, Cackovic says. For example, some women understand and accept it when they see an ultrasound image of their child. But doctors usually recommend a mental health evaluation to figure out what caused them to deny their pregnancy. It’s also an important step to prevent child abuse and neglect, which are more common after denied pregnancies than normal ones.

Why It Matters

Women can and do deliver healthy babies after a denied pregnancy, Cackovic says. But there are risks to not knowing you’re pregnant:

  • You could miss out on the prenatal care that can ensure that you and your baby are healthy, like physical exams, blood tests, and ultrasound scans.
  • You won’t know your or your baby’s risk for complications, like anemia, a type of high blood pressure called preeclampsia, gestational diabetes, or birth defects.
  • You won’t know it’s time to make healthy changes that help your baby grow and thrive, like getting good nutrition, avoiding alcohol, and stopping certain medications.

Know the Early Signs

It’s hard to predict who could have a denied pregnancy. But if you think you might miss some of the classic signs, like weight gain or a missing period, you can watch out for other early signals, such as:

Show Sources


Michael Cackovic, MD, assistant professor of maternal fetal medicine, Ohio State University Wexner Medical Center.\

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Del Giudice, M. Medical Hypotheses, 2007.

National Institutes of Health: “What causes menstrual irregularities?”

Royal College of Obstetricians and Gynaecologists: “Reduced Fetal Movements.”

Lieb, M. Fortschritte der Neurologie Psychiatrie, May 2012.

National Institutes of Health: “What is prenatal care and why is it important?”

Wessel, J. Acta Obstetricia et Gynecologica Scandinavica, 2007.

Mayo Clinic: “Symptoms of pregnancy: What happens right away.”

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