Analyzing the records of nearly 890,000 mothers across 499 hospitals in both states, they found that more women in Texas got the voluntary sterilization procedure after delivery in 2009 than did women in California.

But the differences were not clearly linked to obvious factors - such as cost or religiously affiliated hospitals that refuse to do the surgery. Further, sterilization rates ranged from zero to 15 percent in California hospitals and between zero and 30 percent in Texas hospitals.

"This huge variation we're seeing both between the two states and within facilities raises a red flag," said study author Dr. Daniel Grossman, senior associate at Ibis Reproductive Health. "Our paper raises more questions than it answers," he told Reuters Health.

Differences in federal funding could explain some of the discrepancies. Federal funds through Title X and Medicaid programs reach more women in California than Texas, Grossman said.

In his team's report, published in the journal Obstetrics & Gynecology, the researchers suggest that Texas women have fewer low-cost family planning options, which may act as an incentive to get their tubes tied for contraceptive purposes.

Conversely, the more generous family planning funding in California might mean that women have access to low-cost options beyond sterilization after delivery.

Nonetheless, surgical sterilization remains very popular in the U.S. and nearly a third of women with children use it for family planning purposes, according to some estimates.

A 2011 study from the Centers for Disease Control and Prevention, for example, found that tubal sterilization was performed following every one in 13 births in the U.S. between 2001 and 2008, while insertion of a contraceptive IUD was done after one in every 37,000 births. (See Reuters Health story of August 26, 2011.)

In the new study, Grossman and his colleagues found that in California, one in every 15 women had her tubes tied after delivery, compared with Texas where one in 10 women was sterilized after delivery.

They looked at several factors that might explain the variation in rates, but none stood out as a clear cause. Variation was similar among private versus publicly insured patients and among mothers who delivered by cesarean section - a procedure that might make it easier to have elective sterilization right after delivery.

The age of the mothers also did not explain the disparities. The data did not include the number of previous children the women had.

Differences in accessibility might arise from several other sources, the researchers suggested. Catholic hospitals ban sterilization, but non-Catholic hospitals could also have policies that limit tube tying.

"It doesn't matter if it's at an institutional level or a state level, it's always the least mobile, the poorest (women) who don't have the choice," said Dr. Cori Baill, a physician at The Menopause Center in Orlando, who has counseled mothers in family planning issues.

Baill, who was not involved in the current study, said poor women who lack prenatal care will not have sterilization as an option since Medicaid requires expectant mothers to sign consent forms 30 days before delivery. "It's ridiculous that Medicaid rule still exists," Baill told Reuters Health.

Night and weekend staffing could also affect the variation in tube tying since doctors may not be around to perform the elective surgery, Baill added.

Though the current study did not examine how many mothers requested their tubes tied after delivery, Grossman and colleagues are examining the demand for sterilization in an ongoing pilot study in El Paso, Texas.

"Women across the country should be able to access the form of contraception that they want," Grossman said. "We need more information to determine what accounts for this variability."

SOURCE: bit.ly/Uqx8hQ Obstetrics & Gynecology, online December 20, 2012.

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