Arizona lawmakers gave final passage to three anti-abortion bills Tuesday afternoon, including one that declares pregnancies in the state begin two weeks before conception.

The Republican-controlled House of Representatives passed a bill to prohibit abortions after the 18th week of pregnancy; a bill to protect doctors from being sued if they withhold health information about a pregnancy that could cause a woman to seek an abortion; and a bill to mandate that how school curriculums address the topic of unwanted pregnancies.

All of the bills passed the Senate and now head to Gov. Jan Brewer (R) for her signature or veto.

The 18th week bill includes a new definition for when pregnancy begins. A sentence in the bill defines gestational age as "calculated from the first day of the last menstrual period of the pregnant woman," which would move the beginning of a pregnancy up two weeks prior to conception. The bill's passage would give Arizona the earliest cutoff for late-term abortions in the country; most states use 20 weeks as a definition.

But while the bill's definition of when pregnancy begins is new in legislation, it's not necessarily new for doctors. Elizabeth Nash, states issues manager for Guttmacher Institute, a reproductive health research organization in Washington, said it corresponds with how doctors typically determine gestational age. She said since the exact date of conception cannot be pinpointed, doctors use the day of the woman's last menstrual period to gauge the duration of a pregnancy. The method does not provide an exact date.

"It will have some impact, from what we understand there are abortions provided at that point in Arizona," Nash said. "It will reduce access."

Nash said nationally, 1.5 percent of abortions in the U.S. occur after the 21st week and 3.8 percent occur between the 16th and 20th weeks. She said the bill would violate U.S. Supreme Court rulings on abortion by mandating a cutoff date that is before viability and not having enough provisions for late-term abortions needed to protect a woman's health.

State Rep. Kimberly Yee (R-Phoenix), the bill's sponsor, was not immediately available for comment. Her assistant said that Yee, a former aide to former California Gov. Arnold Schwarzenegger (R), was voting on the House floor.

State Rep. Matt Heinz (D-Tucson), a physician, said he did not want the state to set the gestational age since science could not provide a precise one. "I imagine it will be a legal dispute. How can a judge determine gestational age?" Heinz said. "If medical science can only determine gestational age to within 10-14 days, how can a superior court judge do it?"

The other two bills passed by the House include the state's "wrongful birth, wrongful life" bill that prohibits lawsuits against doctors who do not provide information about a fetus' health if that information could lead to an abortion. In addition, parents cannot sue on the child's behalf after birth.

The third bill requires that schools teach students that adoption and birth are the most acceptable outcomes for an unwanted pregnancy.

All three bills are now headed to Brewer's desk for her review. The governor has not announced a position on the bills, which is her practice, but her spokesman indicated that Brewer has a long commitment to pro-life issues.

Clarification: This text has been altered since its original publication to clarify that the bill's definition of when pregnancy begins is new specifically to state legislation.