DENVER -- The number of expectant mothers around the country diagnosed with influenza is on the rise and a local obstetrician-gynecologist said there's a good reason.

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Pregnant women are basically working double time as they care for the fetus, doctors say.

"The women themselves are at greater risk for catching the flu and other viral infections simply because their immune system is decreased during pregnancy. The women themselves are at greater risk to all sorts of infections that are going around," said Dr. Dan Eicher, with the Rose Medical Center.

Although there's no fetal risk associated with the vaccine, a flu shot is recommended only for women who are at least 13 weeks along.

"Being 10 weeks pregnant, I'm only in my first trimester, and my doctor advised me not to get it yet," said expectant mother Jenny Riojas.

As it turned out, Riojas came down with the flu last week and she found it hard to follow her doctor's orders to the letter.

"I was really restless. I could not sleep, so you're supposed to get as much rest as possible, but I was just laying in bed not actually sleeping 'cause your body is just so sore," Riojas said.

Doctors recommend pregnant women avoid friends and relatives who have flulike symptoms. And if they do happen to get sick, the women are told to take Tylenol and drink lots of liquids.

Health experts say a fetus generally isn't affected by the flu because the virus doesn't usually cross the placenta.

Flu Hits Its Peak In Denver

The flu is being reported in 56 of Colorado's 64 counties. Adams, Arapahoe, Jefferson, Boulder and Larimer counties all have more than 600 cases. Denver county is reporting nearly 1,000 cases of the flu.

The virus is now suspected in the deaths of at least five adults in the state.

Audrey Eleanor Menzie, 82, of Fort Collins had a flu vaccine shot this fall, but the Kansas-born former telephone operator died Sunday. She had suffered from emphysema and cancer, but influenza was listed as the cause of death.

In a spot check around the state, coroners in Jefferson and Adams counties told The Associated Press that they suspect the flu may have contributed to the deaths of four more adults. At least two were over 60.

Those cases are still being investigated by the State Health Department.

So far the flu has claimed the lives of nine children and 7,600 cases have been confirmed. That's more than the 6,286 cases reported in the past three seasons combined.

Fortunately, health officials said they think the flu bug has peaked in the Denver metro area. Even though the number of cases has risen, it's a much slower increase than doctors had previously seen.

"What we're seeing in the Denver metropolitan area is that the flu has peaked and we're on the downward side of the curve. We're very confident we're on the downward side of the curve," said Douglas Benevento, executive director of the state Department of Public Health and Environment.

A drop in flu-related visits to doctors, particularly pediatricians, is also "clear evidence" the outbreak has peaked in and around Denver, Benevento said.

Last year, Colorado had 19 confirmed flu deaths of all ages and 748 deaths due to flu and pneumonia. The elderly and young are considered the most vulnerable because of their weakened or underdeveloped immune systems.

Flu and its complications are the sixth leading cause of death nationally among children 4 and younger. But the Centers for Disease Control and Prevention said it is particularly concerned about a staph infection that is resistant to common drugs.

One epidemiologist with the influenza branch of the CDC said some children have died from the staph infections, a phenomenon the CDC has not seen before.

Flu complications for children have always been dire: pneumonia, kidney, heart failure and possible brain damage. But this year, young flu patients have swamped hospitals in some states and surprised doctors with the severity of their illnesses.

Supplies of the flu vaccine have been dwindling, though the state bought 4,090 additional doses this week and has requested more from government health officials.

The additional flu vaccine will be delivered Thursday afternoon.