Women who undergo in vitro fertilization are advised to make several lifestyle changes, but many women do not always take the recommendations to heart, a new study has found.

Most doctors recommend that women stop or cut back on caffeine, alcohol, nicotine and herbs because it decreases their chances of becoming pregnant. Women are even advised to tone down their exercise regimen, as well.

But new research from  Boston IVF, an infertility treatment center, examined data from 118 women who underwent an IVF cycle between June 2009 and March 2010 and found that many women were not following recommendations. While it appeared most women were generally living healthier lifestyles than in the five years before their IVF cycles, about half of the study participants reported still drinking one to two alcoholic beverages per week. Three percent reported smoking during their IVF cycle.

Patients at the center are advised to limit caffeine consumption to about 50 milligrams (one soda, one cup of tea) per day, but almost half of the patients reported to continue drinking caffeine each day. Most of those caffeine drinkers reported drinking coffee, which can have anywhere between 60 and 200 milligrams of caffeine in one cup.

And even though patients are told to cut back on exercise, about 12 percent reported exercising at least once a week.

"Something like running can be really jarring and painful during an IVF cycle because the ovaries are enlarged," said Dr. Alice Domar, the study's lead author and executive director of the Domar Center for Mind and Body Health of Boston IVF. "While we think going out for a run makes us feel good and feel like we can eat that cupcake later, our bodies take it as we're running from a bear, which is not conducive to your body if you're trying to get pregnant."

While the survey size is too small to make blanket responses and suggestions, Domar said they were surprised by the results because each cycle can cost nearly $20,000, and women really want to get pregnant.

"An IVF cycle is only 28 days, so patients really need to understand that they should maximize their chances of getting pregnant at that time," Domar said. "If it doesn't work, then they can go back to their normal lifestyle habits, but they should really capitalize on their chance if they can."