Laird Harrison

October 30, 2015

SAN DIEGO — A new literature review challenges 70 years of medical orthodoxy by suggesting that women at low risk for aspiration should be allowed to eat solid food during labor.

"My opinion is that we have enough evidence to change the current guidelines," said Michael Bautista, MD, from Memorial University in St. John's, Newfoundland, Canada.

Dr Bautista presented the finding here at Anesthesiology 2015 from the American Society of Anesthesiologists (ASA).

Policies forbidding women in labor from consuming anything by mouth date back to an influential 1946 study by Curtis Mendelson ( Am J Obstet Gynecol. 1946;52:191-205).

Dr Mendelson found a disturbing incidence of women aspirating the contents of their stomachs while under anesthesia during labor, and he recommended fasting as prophylaxis. The idea took root.

Since that time, however, the use of regional anesthesia has increased, as has the use of procedures that reduce the risk for aspiration during general anesthesia, Dr Bautista explained.

In the United States, hospital policies vary widely, said session moderator Jill Mhyre, MD, from the University of Arkansas for Medical Sciences in Little Rock. Some insist that women in labor take nothing by mouth, some allow ice chips, some allow clear liquids, and some allow solid food.

The current ASA guidelines, updated in 2007, recommend modest amounts of clear liquids to satiate thirst for women in labor, with further restrictions on a case-by-case basis for women likely to require general anesthesia and who have risk factors for difficult airway management ( Anesthesiology. 2007;106:843-863).

Those guidelines are not about to change, Dr Mhyre told Medscape Medical News. An update recently submitted to the ASA House of Delegates for affirmation simply confirms the 2007 policy, she reported.

But the evidence does not support these restrictions, Dr Bautista said.

Dr Bautista and colleagues identified 385 studies that included laboring women with in-hospital delivery by a physician after searching multiple databases, including PubMed, Cochrane, and Embase.

Low Rates of Aspiration

They found that aspiration rates were 0.667 per million from 1979 to 1990 and that general anesthesia was used in only 13% of caesarean deliveries from 2003 to 2008. In one study of 746 caesarean deliveries, 22% of the patients ate solid food during labor without any morbidity or mortality.

Risk factors for aspiration include comorbidities such was obesity, preeclampsia, and eclampsia, but the most significant risk factor was failed intubation, which occurred in 1 of between 274 and 465 attempts.

The team attributes low rates of aspiration to the increased use of neuraxial anesthetic, better anesthetist training, and the use of laryngeal mask airways for failed intubations. They also credit the increased use of protocols to determine which women are at greatest risk of aspirating their vomit and to manage difficult airways.

"What we want to do is tailor our management decisions based on the risk factors of the patients, their pregnancies, and their anesthesia," said Dr Bautista. "Hopefully, the majority would be allowed to eat something during labor."

For women who do eat solid food, Dr Bautista recommends light food, such as toast and yogurt.

Gastric emptying is delayed during labor, but there are conflicts in the literature related to gastric emptying delay in pregnancy, the researchers report.

For patients with risk factors for aspiration, the team found support for placing epidural catheters early, because regional and epidural anesthesia does not slow gastric emptying, but opioid analgesia does.

Fasting and Ketones, Lactic Acid

As for fasting, not only is it unnecessary, but it can produce ketones and lactic acid, decreasing the pH of both the mother and the fetus, the researchers report. And although gastric volume initially decreases during fasting, the secretion of low-pH gastric juices continues, which could increase morbidity and mortality, should aspiration occur.

The use of proton pump inhibitors and H2-receptor antagonists to increase the pH of gastric contents and the administration of metoclopramide before delivery to improve gastric emptying make eating during labor safer, said Dr Bautista.

"I think it's time for a moment of reflection," he said. "Have we done such a good job we can now let women have something to eat?"

 
The thing I see driving change is patient demand. Dr Paloma Toledo
 

This is a "nice review," but it doesn't settle the controversy over eating during labor, said Paloma Toledo, MD, MPH, from the Northwestern University Feinberg School of Medicine in Chicago, Illinois.

Only a prospective trial to see whether women fare better eating or not eating during labor will provide definitive evidence, she told Medscape Medical News. Yet such a trial is "impossible," she pointed out. "Aspirations are so rare you would need a really large sample."

So what will resolve the disagreement?

"The thing I see driving change is patient demand," she said. "My personal opinion is that maybe over the next 15 years we will see a change toward solid food consumption during labor."

Dr Bautista and Dr Toledo have disclosed no relevant financial relationships.

Anesthesiology 2015 from the American Society of Anesthesiologists (ASA): Abstract A1130. Presented October 24, 2015.

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