SAN DIEGO (FOX 5/KUSI) — Hundreds of nurses at Rady Children’s Hospital hit the picket lines on Monday after a tentative contract agreement reached in last-ditch negotiations over the weekend was voted down by union members.

The demonstration by nurses with United Nurses of Children’s Hospital (UNOCH) Local 1699 marks the beginning of a historic two-day strike — the union’s first since it was formed over 20 years ago. The strike is expected to end Wednesday morning.

According to the union, the striking nurses have been seeking better pay and benefits in their contract negotiations, demands they say will better patient care by cutting down on turnover and making recruitment efforts more competitive.

A 10-day strike notice was delivered to hospital administration earlier this month after the union overwhelmingly voted down the first contract proposal due to issues with the suggested wages and benefits. Two additional agreements, including one reached Sunday, were similarly rejected.

“While we know the past two weeks have been difficult and the future is uncertain, there is one thing we know we have already won and that’s unity. We have banded together like never before,” UNOCH Local 1699 officials said in an email to its members Sunday night. “Let’s keep up the solidarity on the picket line.”

Rady Children’s Hospital officials have maintained that the contracts were “fair and equitable” in meeting the nurses’ demands.

In a statement on Sunday, the hospital said the last contract reached would have increased the average nurse’s compensation by 25% when compounded over three years and included a base pay market adjustment, updated shift differentials, a refined pay grid and step increases.

The statement did not detail what adjustments were made to benefits under the contract like retirement and health care, which has been a sticking point for the unionized nurses.

“I work two jobs, personally, to make ends meet on top of my husband working,” Alexandra Seanez, a registered nurse at Rady Children’s Hospital, told FOX 5/KUSI on Monday. “I have a child with medical needs who hasn’t even been able to receive specialty care here — even as an employee of Rady Children’s Hospital. They didn’t accept our insurance.”

“We as nurses at Rady Children’s Hospital have some of the worst benefits in the hospital system in San Diego County,” Seanez continued. “Our premiums have gone up 34% in the last few years, our co-pays are getting higher and we just can’t keep up.”

While the union is on strike, Rady Children’s Hospital officials added they will continue to ensure patients can receive care, filling in strike-related gaps with additional pediatric nurses contracted through a professional staffing agency.

“Now our focus turns completely, as always, to the children and making sure that we’re here to care for the kids every single day,” Dr. Patrick Frias, Rady Children’s Hospital president and CEO, told FOX 5/KUSI Monday morning.