(Reuters Health) - Most states have statutes that invalidate a woman’s advance directive if she is pregnant, a U.S. study finds. And because those statutes are often not clearly outlined in the DNR form, women filling out an advance directive most likely would not know that it wouldn’t apply if they were pregnant, researchers reported in JAMA.

FILE PHOTO: A pregnant woman, in the last trimester of her pregnancy, poses in this illustration photo in Sete, South France, March 26, 2016. REUTERS/Regis Duvignau

“Two-thirds of states that had restrictions didn’t disclose that in the advance directive document,” said study leader Dr. Erin DeMartino of the Mayo Clinic in Rochester, Minnesota. “So a person could in good faith fill out a DNR and assume that unless she decides to annul it herself it would be a valid document moving forward.”

DeMartino and her colleagues were surprised at how common the pregnancy exceptions were.

“One of the purposes of our study is to shine a light on where we are in 2019 and to show the American public and medical professionals the prevalence of these laws and how they could apply in the rare medical circumstances where they come up,” she said.

The situation may be rare, but it’s certainly not unheard of for a young woman to end up incapacitated and tethered to life support machines because of a pregnancy statute. In 2014, 33-year-old Marlise Munoz suffered a pulmonary embolism and was pronounced brain-dead upon arrival at the hospital. She was 14 weeks pregnant at the time.

Although Munoz had told her husband and family that she wouldn’t want to be kept alive by machines if she were fatally injured, doctors said they could not disconnect her from life-support. The family was told that even if Munoz had a DNR, a Texas statute forbade them from taking a pregnant woman off life-support. It took a lawsuit by her husband to get permission two months later to remove life-support from Munoz.

To take a closer at the issue, DeMartino and her colleagues used the Nexis Uni and Fastcase databases to search for laws effective in February 2019 that governed treatment decisions for incapacitated pregnant women. They also scrutinized advance directive documents from each state.

The researchers found that 28 states had statutes restricting a woman’s choice to withhold or withdraw life-sustaining therapies because of pregnancy - and 68 percent of the official advance directive forms in those states did not disclose the pregnancy restrictions. Of the 28, 25 had statutes that invalidated a woman’s DNR if she turned out to be pregnant. And three states - Alaska, Georgia and Oklahoma - required that physicians test a woman for pregnancy before withholding or removing life-support.

Two states - Washington and Idaho - did not have a specific statute barring the removal of life-support from pregnant women but did state in their DNR forms that it was not allowed. Eight states’ advance directive documents asked for the woman’s pregnancy-specific care preferences.

While 18 states banned withdrawal of life-sustaining therapy when the treating physician determined the fetus could survive if the mother was kept on life-support, 12 required the woman be kept on life-support regardless of the fetus’s status. In 19 states, surrogates’ decisions were restricted because of pregnancy.

The new findings are “chilling,” said Dr. Albert Wu, an internist and professor of health policy and management at the Johns Hopkins Bloomberg School of Public Health. “It’s shocking that the vast majority of U.S. states actually restrict the rights of women who happen to be incapacitated in this unfortunate situation. I’m disappointed and disturbed by this.”

The statutes described in the new study “are a violation of the rights of women,” said Wu, who was not involved in the new research. “It adds insult to injury that in the majority of cases these restrictions are not disclosed to people when they are expressing their choices in their advance directives.”

SOURCE: bit.ly/2ZsD9RI JAMA, online April 23, 2019.