Newborn hair signals expectant mothers' meth use: study
Last Updated: Tuesday, October 31, 2006 | 10:10 AM ET
A newborn's hair suggests if a woman intentionally took methamphetamines knowing she was pregnant, a landmark Canadian study has found.
The study by researchers at Toronto's Hospital for Sick Children involved tests on hair samples from 8,000 Canadian mothers and newborns collected between 1997 and 2005.
Methamphetamine can be snorted, smoked or injected.
(CBC) As suspected, when expectant mothers use the drug, it moves through the placenta to the fetus. Now researchers have found evidence of methamphetamines in the hair of some newborns.
Fetal hair does not start growing until the last three months of pregnancy, the study's principal author, Dr. Gideon Koren, told CBC Newsworld on Tuesday.
"If you find it in a baby, it has to get there," said Koren, head of the hospital's Motherisk program. "Babies do not do drugs, so it's Mum who had to do it."
If the drug is present in a baby's hair, its an "ominous sign of addiction."
While blood and urine samples cannot determine long-term use or differntiate between various drugs, the new test is accurate and sensitive, Koren said. Hospitals and child protection agencies are using it to track the extent of the problem.
Methamphetamines, including crystal meth, are powerful stimulants that boost alertness and cause euphoria. But the highly addictive drugs also depress appetite, and long-term use can lead to brain damage and psychotic behaviour. The drug causes blood vessels to constrict, and may prevent blood from reaching vital organs.
Because crystal meth is relatively easy to make and buy — it can be cooked up in home laboratories with accessible ingredients and bought for $5 to $10 a hit — global use of the drug is skyrocketing, especially among young women, the researchers say.
'It's a looming epidemic; it's like a big black cloud.'
— Dr. Gideon KorenWhile national statistics for Canada are not readily available — figures vary from province to province — an estimated 500,000 Americans are believed to be regular users, including five per cent being pregnant women.
More addicted mothers expected
The study was published online ahead of the print version of the fetal and neonatal edition of the Archives of Disease in Childhood.
The hair samples were sent by doctors or children's aid societies to Sick Children's Motherisk Laboratory for analysis.
Almost 400 of the hair samples tested positive for meth. The number included 11 mother and baby pairs.
The first positive cases — six in all — were found in 2003. The next year, eight hair samples contained evidence of methamphetamine use. But in 2005, the number soared to more than 300.
"It's a looming epidemic; it's like a big black cloud," said Koren. "For sure we know that a significant group of Canadian kids have addicted mothers.
"I expect … we will see more and more."
Methamphetamine users were also more likely to use other drugs, the study found. In fact, 85 per cent of the 396 samples that came back positive for meth also tested positive for at least one other illegal drug, predominantly cocaine.
While the short- and long-term effects of methamphetamines on the developing fetus are not fully known, Koren said animal and small-scale human studies suggest the drug may affect normal growth and development.
The blood-brain barrier in a fetus is much more permeable than that of an adult, "so there's no question whatsoever that it goes into the brain of the baby," Koren explained. "There's all the theoretical reasons to believe it will have long-term effects on the babies.
"That's the next thing we're going to do — we will follow up these babies."
Poor nutrition a concern for mothers
Wende Wood, a psychiatric pharmacist at the Centre for Addiction and Mental Health in Toronto, said babies whose mothers abused drugs during pregnancy tend to be born prematurely and underweight.
It is difficult to tell, however, whether these babies are underdeveloped because of drugs or because the mother wasn't caring for herself properly during pregnancy, Wood said. A big problem for some people taking methamphetamines is eating properly.
"With stimulants in particular, like meth and cocaine, they suppress the appetite. So a lot of the problems could be just as much from the poor self-care and poor nutrition as from the drug itself."
Dr. Heather Scott, a maternal-fetal medicine specialist at Nova Scotia's IWK Health Centre, said the study confirms the long-held suspicion that methamphetamines do enter the placenta and subsequently the developing fetus.
'My gut feeling … is that [methamphetamine use] is on the rise, but I think we're not very good at getting a handle on it.'
作者:admin@医学,生命科学 2011-06-16 17:11