Kimberly Fugate thought she was having triplets, until the Mississippi mother gave birth to a fourth, identical twin. Doctors were shocked when they saw a fourth set of feet that had not been detected in ultrasounds.

Fugate and her husband, Craig, were not planning on having additional children after the birth of their now 10-year-old daughter. Surprised by the pregnancy, they were even more shocked when they discovered they were having triplets. Now, floored to learn of a fourth baby, the couple are ecstatic of the additional birth.

With a 1 in 13 million chance of birthing identical quadruplets, the birth marks only the 60th recorded birth of identical quadruplets to date. The quadruplets were born at the Winfred L. Wiser Hospital for Women and Infants at the Mississippi Medical Center in Jackson, Miss., on February 8, where they have since been in the neonatal intensive care unit and are reportedly doing well.

Fugate, age 42, endured an extensive labor that included a cesarean section. Reports indicate that the fourth baby was not identified during previous ultrasounds.

In an interview with CNN affiliate WAPT, Fugate recounts the experience, saying that she heard the doctors say, “More feet,” to which she responded, “No!” Explaining that it had come as an instant shock.

The odds for birthing quadruplets conceived without the use of fertility assistance is 1 in 729,000, a number much smaller in comparison to the odds of birthing identical quadruplets, which result from the four-way split of a single egg.

The last reported case of identical quadruplets being born occurred in January of 2012 in Germany. Prior to the birth of these German quadruplets, other cases have been documented, including the birth of the Mathias quadruplets. Now middle school aged, these girls previously appeared on the Discovery Health Channel show “Super Quads.”

Because the Fugate babies were born so prematurely, a spokeswoman for the hospital said it may be until early May until the babies are released from the hospital.