A 23-year-old Massachusetts woman Katherine Kropas delivered a baby girl an hour after learning she's pregnant. Katherine woke up with sharp and sudden pains in her stomach and back Tuesday morning. The pain felt as if she was getting stabbed in lower back.

She was admitted to the South Shore Hospital's emergency room in South Weymouth Massachusetts and spent the day undergoing tests to see what was causing her pain. Her 40-year-old boyfriend Dan Keefe was with her.

Initially, blood tests indicated she was five weeks pregnant. As the nurses examined her Tuesday night, they noticed that she was 9 centimeters dilated and about to give birth.

Less than an hour later, Katherine gave birth to a healthy baby girl named Ellen Olivia Keefe in emergency C-section. The surprise baby girl weighed 10 pounds, 2 ounces.

Katherine mentioned that there was no morning sickness or other clues that indicated that she might have been pregnant over the last few months.

She did notice that her ankles were swollen and a bit of blood. She thought that she had put on some Christmas season weight. But she had no idea that she was pregnant.

According to Dr. Kim Dever, chair of the Obstetrics and Gynecology at South Shore Hospital, what Katherine went through is known as a 'cryptic pregnancy'. It happens when a woman is overweight or has irregular periods.

According to pregnancycorner. com, one out of every 475 pregnancies is a cryptic pregnancy and one out of every 7,225 women learn about their pregnancy when they are going into labor.