Doctors are prescribing opioid painkillers to pregnant women in astonishing numbers, new research shows, even though risks to the developing fetus are largely unknown. Pain relief options for pregnant women are limited at best. Nonsteroidal anti-inflammatory drugs are rarely used because there is evidence of potential risk to the fetus in the third trimester. “If the pain is so severe that acetaminophen is not enough, we have no analgesic option besides opioids,” said Dr. George Saade, the director of maternal-fetal medicine at UTMB, who was not involved in the study. The Best Pharmaceuticals for Children Act of 2002 has helped stoke research into safer drugs for the pediatric population, he noted. “But we haven’t had anything similar for pregnant women,” he said.