How Women Sometimes Don't Know of Their Pregnancy Until It's Time to Give Birth

Shaun Jude Jaegers was born at 3:50 a.m. on the morning of October 19, 2016, about three hours after his mother found out she was pregnant. His mother Stephanie Jaegers had only checked into a hospital with severe abdominal cramps six hours earlier.

At age 37 and already the mother of three children, Stephanie and her husband Michael had decided they were not having any more babies. They had given away their other children's baby clothes. They had stowed the car seat in the attic. There had been no signs of a pregnancy. Stephanie was having her period, maybe not as regularly as usual, but that had to because she was approaching menopause. She had looked a little bloated for a few months, but she hadn't looked pregnant.

So when Stephanie started having waves of abdominal pain on October 18, 2016, she thought she had kidney stones. After all, she had given birth three times. She knew what labor pains felt like. In the ER of Piedmont Henry Hospital in Stockbridge, Georgia, however, the doctors decided to run a pregnancy test just in case. 

How a Georgia Woman Carried a Baby For 38 Weeks Without Symptoms of Being Pregnant

Sure enough, Stephanie was giving birth.

How could Stephanie and Michael possibly have not known that Baby #4 was on the way? It turned out that:

• The baby was breech, aiming its posterior section at the world. His feet were up near its head, so Stephanie never felt him kick.
• Baby Shaun managed to spend nine months behind a rib, so Stephanie did not have a bulging tummy.
• Mother Stephanie was already premenopausal, so hormonal changes were not obvious.

By the time doctors confirmed that Stephanie was pregnant, she was already fully dilated. Even though her water never broke, the baby's butt was visible through the cervix. Doctors at first thought that they would have to do a Caesarean section, but Stephanie was able to give birth naturally, and Baby Shaun arrived healthy and beautiful into the world.

READ Are You Pregnant? The Very First Pregnancy Symptoms

Undetected Pregnancy Is More Common Than You Might Think

Stories like that of Stephanie Jaegers appear in the news with frequency. In November 2015, the newspapers reported the case of  47-year-old Beverly, Massachusetts resident Judy Brown, who entered a hospital thinking she was having a severe gallstone attack and gave birth to a healthy daughter just one hour after she found out she was pregnant. She and her husband had been married for 22 years and had even stopped thinking it was possible to get pregnant.

In January of 2015 a 23-year-old Wisconsin woman who had had a menstrual cycle and was on birth control, and who had had no signs of pregnancy other than swollen feet, gave birth to a healthy 10-pound (4.5 kilogram) baby girl. And in 2012 a British soldier who had no idea she was pregnant gave birth to a baby boy on the front lines in Afghanistan.

A German study of births in metropolitan Berlin found that 1 in 475 mothers did not know they were pregnant until 20 weeks into their pregnancies. The study also found that 1 in 2,455 did not know she was pregnant until she was in labor. Cryptic pregnancy is not an exotic, unheard of condition.

How Can Women Miss the Symptoms of Being Pregnant?

Women aren't going to use pregnancy tests or pregnancy calculators when they don't think it's possible that they could be pregnant. And it turns out that women who give birth without ever having known they are pregnant haven't lost their minds. They almost always just experience unexpected variations in their anatomy and the activity of their endocrine systems.

• The Pill doesn't always work. It's possible to become and stay pregnant even while taking oral contraceptives. 
• Women who have cryptic pregnancies may have abnormalities in the production of human Chorionic gonadotropin, also known as hCG. This hormone enables the ovary to release an egg during the ovulation cycle and then stimulates the uterus to release progesterone during early pregnancy so it thickens and provides more blood vessels to provide oxygen and nourishment to the embryo. Levels of hCG peak about the same time as morning sickness. If a woman's body is producing less hCG, she may not have morning sickness. However, if she doesn't know she is pregnant and continues taking a high-progesterone oral contraceptive, the Pill may ironically help her stay pregnant.
• Many women who go through cryptic pregnancy develop amenorrhea (irregular periods) that they mistake for menopause. They may even stop using contraception because they think they cannot become pregnant.
• In one study of cryptic pregnancy, none of the women had suffered morning sickness. 
• Women may have a "period" even when they aren't going through their normal ovulation cycle. It's more likely this is due to bleeding associated with pregnancy, coming at irregular times that women assume is due to their approaching menopause.
• The overwhelming majority of women who have undetected pregnancies are psychologically healthy. A study in Europe found that about 5 percent had psychiatric issues like schizophrenia, and about 8 percent were intellectually challenged.

READ Early Pregnancy Symptoms and Signs

• Although the examples cited above involved healthy, normal weight babies, low birth weight babies are more common in cryptic pregnancies. Mothers of low birth weight babies may gain very little or even no weight while they are pregnant. About 20 percent of infants resulting from undetected births weigh less than 2500 g (5.5 lbs) at birth. This may explain why some mothers don't experience morning sickness or abdominal swelling in their pregnancies.
• Women who become pregnant after the age of 35 don't have as much estrogen production during pregnancy. Their breasts may not enlarge. They may not have the "glow" that sometimes comes with pregnancy. 

Even where late-term abortion is available, women who discover they are pregnant late almost never have the procedure. Women who have cryptic pregnancy usually turn out to be "good mothers" in several senses of the term. Babies born after undetected pregnancies, surprisingly, tend to be healthy, despite the fact their mothers did not know to take precautions with medications, radiation, alcohol, and drugs during pregnancy. When there are complications, they are most likely to be due to low birth weight or the surgical procedures needed during delivery.