AUSTIN - Texas clinics have performed 10 percent to 15 percent fewer abortions since the state enacted strict requirements two years ago for women seeking the procedure, according to preliminary findings of a new study.

But researchers said Wednesday that shift appears to stem more from obstacles created by the 2011 laws - including a 24-hour waiting period and mandatory ultrasounds - than from women changing their minds because of them.

"Our findings so far indicate these regulations do not positively impact women's decision-making and, in fact, are burdensome for women," said Dr. Daniel Grossman of Ibis Reproductive Health, a Massa­chusetts nonprofit focused on improving "women's reproductive autonomy."

The study - conducted by researchers at Ibis, the University of Texas and the University of Alabama at Birmingham - was based on data collected from the state's three largest abortion clinic systems, as well as surveys of more than 27 individual clinics and 300 women from across the state.

Grossman emphasized the final results will not be published until later this year, but the preliminary findings offer the first glimpse of how the state's tougher abortion requirements have affected the prevalence of the procedure.

The Department of State Health Services, which also collects abortion data, has not yet released official numbers for 2011 or 2012, the two years after Texas' stricter laws were passed.

"There has been an overall decline nationally in abortions," Grossman said. "But this appears to be more pronounced."

More waiting, expense

According to the study, women had to wait on average 3.7 days between their initial consultations with a doctor and their abortions - nearly four times the period required by law - because of difficulties with clinic scheduling.

For the two doctor visits, they traveled an average of 84 miles round-trip and typically incurred additional costs of about $146 for travel expenses, child care and lost wages, the research suggests.

And despite the waiting period, 89 percent indicated they were as sure about their decision to have an abortion before their initial consultation as they were afterward, the study found.

The 24-hour waiting period was just one in a series of tighter abortion provisions passed by lawmakers in 2011. The Republican-controlled House also cut funding to family planning that year, and it overwhelmingly voted to require doctors to explain the possible medical consequences of abortion as well as provide women seeking the procedure with an audio recording of the fetal heartbeat.

Advocates for the laws argued that they would allow women to make better-informed decisions about whether to have an abortion.

"As a woman and a physician, I would be concerned about any non-emergency procedure where the patient doesn't ever meet or have a prior relationship with their doctor," State Sen. Donna Campbell, R-New Braunfels, said Wednesday.

But abortion rights advocates described the measures as misguided attempts to control women's reproductive rights.

Kicking off this year's legislative session, Texas Gov. Rick Perry has pledged to back efforts that would further impede abortion availability.

"The ideal world is one without abortion," Perry told a crowd rallied at the Capitol in January. "Until then, we will continue to pass laws to ensure that they are rare as possible."

So far, multiple bills have been filed that would further restrict access to abortions, including one that would shorten the window in which a woman could undergo an abortion to 20 weeks after conception - the point at which many anti-abortion activists argue that a fetus begins to feel pain.

Well-being not goal?

"These measures have nothing to do with the well-being of women and everything to do with their manipulation," state Rep. Jessica Farrar, D-Houston, chair of the Texas Womens' Health Caucus, said Wednesday.

Farrar said she intends to introduce a bill this week that would roll back the 24-hour waiting period requirement, but conceded that its chances of passing were slim.

"I'm not expecting a miracle to happen," said Farrar, who chairs the Texas Womens' Health Caucus. "But if we walk away from what happened in the last session, everyone will think that this is OK."