Cryptic Pregnancy (“I Didn’t Know I Was Pregnant!”)

Believe it or not, it is sometimes possible for a woman to carry a baby all the way to term without ever realizing she is pregnant. This is called a cryptic pregnancy, and it happens more often than one might think; according to one study, one out of every 475 pregnancies is a cryptic pregnancy, unknown to the mother until after the 20th week, and one pregnant woman out of every 7,225 learns of her condition when she goes into labor!

While most women experience typical pregnancy-related symptoms such as morning sickness, weight gain, and missed periods, some women either have no symptoms at all or experience such mild symptoms that they dismiss them or mistake them for some other condition. In rare cases women who are already in their third trimester make appointments to see a doctor because they don’t feel well, only to discover a surprising reason for their fatigue and upset stomach. The patient responds to the news with shock: “I didn’t even know I was pregnant!” she says … and her friends begin to suspect that maybe she’s not one of the sharpest knives in the drawer.

Not Noticing a Missed Period Caused by Cryptic Pregnancy

The first thing most people think when they hear about a woman who didn’t realize she was pregnant until she was about to give birth is, how could she possibly have failed to notice that she wasn’t getting her period? But not all women have equally regular menstrual cycles, and the regularity of those cycles can easily be affected by birth control (which is not always 100 percent reliable) or by obesity (see below).

Furthermore, spotting and light bleeding sometimes occur during pregnancy (although they are uncommon), and some women—especially those who have irregular periods to begin with—can mistake this for their period. Even if she does not experience bleeding, a woman who is accustomed to irregular menstruation may not notice the stoppage of her periods for a couple of months, and when she does notice, she may attribute it to stress. Also, perimenopausal women (women in the early stages of menopause, whose bodies are transitioning into the infertile stage of their lives) sometimes believe incorrectly that menopause is completely behind them and that they can no longer get pregnant.

False Results from Pregnancy Tests

As has been discussed elsewhere on this site, pregnancy tests sometimes produce false negative results if they are taken too soon after conception, or if the woman taking the test fails to follow the instructions properly. Pregnancy tests are designed to detect the hCG hormone, which does not appear in the body at detectable levels until a few weeks after conception has occurred. Also, sometimes they are negative for a few minutes after the test, but 15 minutes later (by which time they are usually in the trash) they finally turn positive.

Gaining Weight Without Realizing You’re Pregnant

Carrying a fetus all the way or nearly all the way to term without realizing it is more common in women who are overweight or obese; the more weight you’re carrying to begin with, the more easily you can fail to notice if you gain a few more pounds. Of course the protruding, rounded appearance of a pregnant woman’s belly looks very different from the ordinary sort of weight gain normally attributed to poor eating and exercise habits, but while most women’s bodies acquire this shape during pregnancy, some do not.

It also bears repeating that women who are overweight often experience menstrual irregularities. This is because fat stored in the buttocks and abdomen manufactures a chemical called androstenedione, which is then transformed into estrogen, throwing hormones out of balance.

True Stories of Women Who Didn’t Know They Were Pregnant

In September of 2012, a British soldier named Lynette Pearce gave birth to a baby boy on the front lines of an Afghan war zone. The child was born six weeks prematurely, and Pearce had not suspected she was pregnant prior to going into labor.

That same month, another Englishwoman, twenty-six-year-old Kayley Straker, began to experience severe abdominal pains, which a nurse at the National Health Service told her over the phone were just chronic constipation for which she should take prune juice. Hours later, Ms. Straker was in the hospital giving birth to a baby boy. She claims that her periods were consistent throughout her pregnancy, and that she never got a “baby bump.”

In October 2013, twenty-two-year-old Nadia Watson of Somerset, England woke to excruciating pains that she assumed were menstrual cramps—until she collapsed and went into labor on her bathroom floor. In the throes of childbirth pains without the benefit of medical pain relief, she screamed so loudly her neighbors called the police—while her boyfriend slept soundly in the next room, oblivious to the entire drama. Throughout her pregnancy Ms. Watson gained very little weight, remaining a size 10 even on the day she went into labor (in American terms that’s a size 8). She had experienced some back pain, but like Ms. Straker, she claims to have gotten regular periods throughout her pregnancy. The most likely explanation in both women’s cases is that they were experiencing the kind of light bleeding and spotting that occurs in many women’s pregnancies, and mistook this for menstrual bleeding.

In December 2013, a woman named Amanda went to see her doctor for severe lower back pain. She had a history of rheumatoid arthritis, so back pain was normal to her. She had been working 12- to 15-hour days at Wal-Mart since receiving a promotion a few months before, and she was not eating well. She was also using Depo-Provera for birth control, a method well known to cause a complete absence of periods. Fifteen minutes after the doctors figured out she was in labor and got her transferred to the birthing unit, she gave birth to a 6 lb. 8 ounce baby girl!

Other Missed Signs of Cryptic Pregnancy

Other factors that can contribute to a woman not knowing she’s pregnant include:

  • Ignorance: while most women understand that pregnancy means their periods will (probably) stop and that their bodies will change shape, not all women are well-informed enough to notice subtler signs such as breast tenderness, constipation, etc. If the woman does not gain much weight and she continues to bleed while pregnant, she may not realize she is pregnant.
  • Failure to feel fetal movement. If the placenta is positioned at the front of the uterus (this is called an anterior placenta), the baby’s movements may not be felt as plainly. Also, when a woman truly believes she cannot become pregnant (due to her use of an IUD, or due to many years of trying without success, for example), she can fail to correctly interpret fetal movement, and can convince herself it is just indigestion or gas.

Possible Complications of Not Knowing You’re Pregnant

If you are experiencing some pregnancy symptoms but not others, or even if you just “don’t feel right,” you should make an appointment to see your doctor as soon as possible. A woman who is pregnant needs to take care of herself in specific ways; she needs to eat right and abstain from smoking, narcotics, and especially alcohol while she is pregnant. A woman who drinks every day during pregnancy risks giving birth to a baby with fetal alcohol syndrome.

It is also important that you begin seeing an ob-gyn as early in your pregnancy as possible so that you can be tested for a number of potentially serious pregnancy complications, including:

Medical References:

    National Center for Biotechnology Information, U.S. National Library of Medicine CNN The Daily Mail The Daily Mirror The New York Times tinybluelines blog
[Page updated June 2015]