ST. LOUIS - Becoming pregnant at age 47 wasn't a worry for Robin Brussel. "I enjoyed every minute of being pregnant," she said.

Still, it was a surprise. "I thought I was going through pre-menopause," she said. "It just happened."

Brussel, now 48, gave birth in December to a 6-pound, 10-ounce boy named Noah she carried for 39 weeks. He was a cesarean birth, as were her four older children, ages 18 to 28. Noah was the first child born to her and her husband, Mark Brussel, 56. They've been married nearly four years.

Their family includes Robin's children, plus Mark's two children; his oldest is 36.

"When Noah came home, all the kids were there; everyone wanted to hold him," she said. "He was very welcome."

She chuckled that the new baby already is an uncle to the couple's grandchildren who are in their mid-teens.

Noah's arrival wasn't the most trying part of her recent life.

In recent years, she has had surgery to remove a vascular condition, similar to a brain aneurysm, and surgery to remove an abdominal tumor that cost her one kidney.

During the pregnancy, she developed gestational diabetes and a rapid heartbeat. She has chosen not to breast-feed because of the medications she's taking.

"None of that was a threat to the child," said Dr. Raul Artal, Brussel's physician during her pregnancy. "We just kept a close eye on her, and the child was healthy throughout.

"I think we met every week and she followed every instruction to the letter," said Artal, head of the department of obstetrics and gynecology and women's health at St. Louis University. "She was an ideal patient."

Artal called Brussel's case unique. Any pregnancy over 35 is defined by the National Institutes of Health as high-risk. But, "All pregnancies are risky," Artal said. As a woman gets older, the risk increases for issues such as genetic disorders and miscarriage.

Brussel's pregnancy passed all of the tests trouble-free, he said.

"I can't say this happens a lot, but I have seen a few in my career," he said.

Artal is a specialist with risky pregnancies.

Many pregnancies later in life tend to be through in vitro fertilization, he said. But statistics are vague because record keepers often don't distinguish between natural and assisted conceptions such as in vitro fertilization.

The National Vital Statistics Report, issued by the Centers for Disease Control and Prevention, says the number of women having children after age 45 is the only U.S. birth rate that has increased, trending upward since 1992. Birth rates for other ages have decreased.

Births to women ages 45 to 49 rose 3 percent from 2008 to 2009. In context, however, that still amounted to only a few hundred total births. In 2009 the younger age groups accounted for 4.3 million births.

"When she told me she was pregnant, I said, 'Unbelievable. It's gotta be a mistake, you gotta go to the doctor,'" Mark Brussel said.

"My concern was that they were healthy," he added. "When the doctor said that, I was excited about it."

Being a dad at this age will help keep him young, he said. Teaching Noah how to throw a baseball and other sports, "I'm sure gonna try," he said.

He is looking forward to fatherhood duties despite his age. "I like it," he said. "... I lost a daughter when she was 18 years old in a car accident. Maybe this is God's way of repaying me."

Robin Brussel said she realizes when she's 60, baby Noah will be 12.

"But with the way our children are with him, I know he's going to be loved and cared for no matter what happens to us," she said.

"The children, they think it's great," Mark Brussel said, "especially my oldest daughter.

"It's like a new beginning, another chance. Enjoy it. That's all I can say."

At Noah's one-month doctor visit, he weighed more than 8 pounds.

"I love him. I'd do it over again," Robin Brussel said. Still, she says she and Mark have taken precautions to prevent another pregnancy.

"Why push it?" she laughed.