Women who have had surgery and continued to use opioids to control post-operation pains during pregnancy have a greater risk of having an infant showing withdrawal symptoms at birth, according to a study published Monday in the Canadian Medical Association Journal.
The research, led by Dr. Nathalie Auger of the CHUM Research Centre, studied data from almost 2.2 million births in Quebec between 1989 and 2016.
“Use of opioids for pain control after surgery may increase the risk of dependence in women and withdrawal in their newborns,” said Auger.
The opioid crisis in the United States and Canada has led to an increasing number of infants with neonatal abstinence syndrome (NAS), which is a withdrawal symptom caused by the sudden interruption of drugs in the system at birth.
The retrospective study found that almost 11 infants out of 10,000 showed withdrawal symptoms.
“Oftentimes after surgery, women will receive opioids for pain control and very little is known on what happens to these women after they are discharged from the hospital,” said Auger.
Mothers who had surgery before pregnancy had 1.6 times the risk of having a baby with NAS. After birth, symptoms can include fever, respiratory complications, weight loss and seizures; long-term symptoms could include mental and behavioural disorders or ophthalmological disorders.
“If the child had (NAS) at birth, it means that they had been exposed to opioids while the woman was pregnant,” said Auger. Although the researchers didn’t know the type of opioid or the dosage the mother was taking, they knew whether she had surgery before her pregnancy.
Infants whose mothers had been taking opioids for longer periods of time had a higher risk of showing withdrawal symptoms, according to the study. “If you continue taking the opioids, it becomes less effective and you need to have stronger doses over time in order to achieve the same pain relief,” said Auger.
The type of surgery also affected the risk of withdrawal symptoms. The study found that cardiothoracic surgery increased the risk by 4.5 times, while neurosurgery and urologic surgery increased the risk by three times.
The association between women who underwent multiple surgeries and NAS was even stronger, according to the study.
Some women whose infants showed withdrawal symptoms hadn’t undergone surgery. “Those are women who would have started opioids for other reasons,” said Auger.
“Maybe they had back pain and the doctor prescribed them opioids, or they got it from their friend who had some left over in their medicine cabinet, or they were actual drug users,” she speculated.
“Opioids continue to be overprescribed,” said Auger. “I think the main issue is that pain control is not a simple thing; it’s complicated. Sometimes it’s hard to know how and which medicine a patient needs when they are in pain, and a lot of times prescriptions are given to patients who might not need as much as they have been given.
“Limiting post-operative opioid exposure, reducing overprescribing, and screening for opioid use in pregnant women who have had previous surgery may help reduce the risk of neonatal abstinence syndrome,” she added.
Copyright Postmedia Network Inc., 2019