Kansas woman expecting 2 sets of identical twins

Christina Tetrick says the news was "just a shock."

WICHITA, Kansas (CNN) -- First-time mothers are taught to prepare for complications in pregnancy. But multiplication -- in Christina Tetrick's case, two babies times two babies -- is something else together.

The medical team treating the Wichita, Kansas, resident believes she will soon give birth to two sets of identical twins, all boys.

The number of multiple births nationwide has risen steadily in recent years, as fertility drugs become more prevalent. There were 114,307 twin and 6,742 triplet births in 1999, according to the National Center for Health Statistics. But quadruplets remain rare, with 512 such sets born in the United States in 1999.

Tetrick's doctor, Scott Roberts, has a hard time himself grasping how one mother could give birth to two sets of identical twins, already rarer than fraternal twins, on the same day.

VIDEO Sahar El-Hodiri of CNN affilliate KAKE reports a Wichita, Kansas, woman is pregnant with two sets of identical twins without the aid of fertility drugs (January 24) Play video (QuickTime, Real or Windows Media)   RESOURCES National Center for Health Statistics: Multiple births

"The fact she has quads is rare enough," Roberts said. "That one set would be identical is rare. And that both sets are identical -- I just really have no idea."

Father called to active duty

When Tetrick and her husband Pat visited the doctor's office several weeks back, she had been told to expect one set of twins. But she had an inkling that a little more was in her future.

One of the doctors asked, " 'Do you want to know the sexes?' " Tetrick said. "And I said, 'I want to know the count. If you happen to see the sex, that's great.' "

As the doctors examined the sonogram, a hush fell over the room -- then one said, "Honey, you have four babies in your belly," Tetrick recalled.

Tetrick's husband, Pat, was recently called to active duty.

"It was a good thing I was laying down, and my husband said it was a good thing he was sitting down, because that was just a shock," she said.

Her doctors said they cannot be certain Tetrick is carrying two sets of identical twins -- which they jokingly refer to as "Team A" and "Team B" -- until the babies are born. But with delivery day fast approaching, the doctors say they are more and more sure of their prognosis.

With the babies healthy, one of the most difficult things about the pregnancy for Tetrick has been the absence of her husband, Pat. A U.S. Army reservist, Pat Tetrick was recently called to active duty.

"As soon as I got pregnant, (Pat said) he wanted to go to every doctor's appointment. He didn't want to miss one," said Tetrick, who has been sending her husband sonogram pictures of their new babies. Being without him is "really hard."

-- Sahar El-Hodiri of CNN affiliate KAKE-TV contributed to this report.