For the tiniest infants — those born before 25 weeks in the womb — survival is never guaranteed, and those who make it may be left with severe disabilities.

These micro-preemies are born in what’s known as the “grey zone.”  Whether or not to resuscitate them depends on the decisions made by individual hospitals, doctors and parents. Decisions can vary greatly even among hospitals in the same area.

A new statement from the American Academy of Pediatrics aims to improve the way those decisions are made. The statement suggests that doctors individualize counseling for parents based on the particular baby’s chances of survival and the family’s goals for their child.

“People sometimes will say at this gestational age you should do nothing and at this you should do everything, but there are many shades of grey,” said Dr. Kristi Watterberg, chair of AAP’s Committee on Fetus and Newborn. “It’s really difficult to tell people prescriptively what you must or must not do. We don’t know.”

Watterberg, who is a professor of pediatrics at the University of New Mexico in Albuquerque, said outcomes for babies born so early are constantly evolving as the medicine used to keep them alive improves.

“We’ve been having the same discussion for many, many years, but the gestational age at which we thought we couldn’t do anything was wrong and keeps changing over time,” she said.

Infants born before 22 weeks gestation are almost never resuscitated. Survival before 23 weeks without significant neurologic impairments “is extremely rare… even with full resuscitation and intensive care,” according to the report, which considers 22 weeks the lower threshold of viability.

But outcomes for babies born all the way up to 25 weeks gestation are often poor. “Most surviving pre-term infants born before 25 weeks gestation will have some degree of neurodevelopmental impairment and possibly long-term problems involving other organ systems,” according to the report.

Outcomes for each individual case are difficult if not impossible to predict. Some babies can beat the odds and survive without major disability. Babies born at higher birth weights, singletons and females, for example, tend to have better chances of survival.

With so much uncertainty, the final decision of whether to resuscitate and provide intensive care to a micro-preemie usually falls to the parents.

“[T]he risk of permanent, severe neurodevelopmental and other special health care needs affect both the infant and the family and, for some parents, may outweigh the benefit of survival alone,” according to the report. For others, even the slimmest chance of survival is reason to pursue all possible medical options.

Some families base their decisions on statistical chances of survival, while others, rely more on religion, spirituality and hope.

The AAP asserts that physicians should be “sensitive to the religious, social, cultural and ethnic diversity of the parents” – and to any language barriers for non-English speaking parents.

Whenever possible, decisions about whether to resuscitate should be made before the birth, the academy says. And visual aids, including graphics and pictures can help enhance parental understanding of possible complications.

Dr. Liz Rogers, a neonatologist at the UCSF-Benioff Children’s Hospital in San Francisco, is spearheading an effort among hospitals in Northern California to better standardize the process of decision-making on such infants.  Rogers says she’s pleased that the AAP is recommending an individualized approach to counseling families rather than specific recommendations for babies at various gestational ages.

But she is concerned that the AAP report is overly optimistic overall about survival.

“I worry that the message being delivered to many pregnant women is that the outcomes are better than they really are. It still requires aggressive, intensive painful procedures to have the babies survive, and many may still have a bad outcome.

“As a general practice, most of us don’t consider 22 weeks to be viable,” Rogers said.  “What I worry about is that we won’t know that we’re at the limit of viability until we’ve gone beyond it and are looking back at it.”

Doctors may paint very different pictures of survival based on their own values and experiences, she said, and families may not understand the risks. It’s crucial, she said, that doctors communicate that they will support simply providing the baby with comfort care as much as they support an aggressive resuscitation.

• Gold wrote this story while participating in the California Health Journalism Fellowship, a program of USC’s Annenberg School of Journalism.