Over half of the respondents in a survey of 1,000 American adults feared that they might not have affordable health insurance in the future, with women more worried than men.

Fifty-seven percent of women and 51 percent of men in survey sponsored by New York-based Bankrate.com responded that they were very worried or somewhat worried that they would not have access to affordable health insurance in the future. More than one-fifth of women responded that they were very worried about not being able to afford coverage, versus 14 percent of men.

Women were more likely to be insured than men, with 93 percent of the women in the survey carrying health insurance versus 88 percent of the men.

Nevertheless, one in four women respondents said that they or a family member in their household avoided going to the doctor over the past year because it was too expensive—even though they needed medical attention. Only 18 percent of men responded similarly.

Nearly half of the women in the survey who had paid a medical bill in the past 12 months, 47 percent, said it was more expensive than they had expected, versus 35 percent of men.

Significant portions of the insured respondents were avoiding doctor’s visits—22 percent of those with employer coverage and 29 percent of those who had purchased their own coverage admitted that they or a member of their household had avoided a visit because they were worried about the costs.

According to Bankrate.com, pre-retirees aged 54 to 63 were the most concerned about losing health insurance in the near future, while older millennials aged 28 to 37 were the most likely to be caught off guard by a higher-than-expected medical bill.

The survey was conducted in July.