Smoking weed during pregnancy can give a developing baby a higher risk of addiction – but only if it's a boy, rat study suggests
- In recent years, the number of American women who use marijuana during pregnancy has increased, despite the advice of many doctors not to
- Little is known about how the use of marijuana by a pregnant woman affects her fetus
- An Italian study found that the brains of rats exposed to THC, the psychoactive ingredient of weed, produce more dopamine in the womb
- But the phenomenon was only true in male rats, the study by Cagliari University showed
- Excess dopamine is linked to a greater risk of addiction and risky behavior
Use of cannabis during pregnancy can cause harmful brain changes in a developing baby – but only if it is a boy, a new study in rats suggests.
Male rats exposed to THC – the ingredient in marijuana that makes users high – while they produce more dopamine in the womb as they grow up.
In people, the neuro-transmitter increases the pleasure of activities such as gambling, sex and addiction.
The experiments showed that it changed the brains and behavior of the lab rodents. The same did not apply to female offspring, says the international team.
Corresponding author Dr. Miriam Melis of Cagliari University in Monserrato said that exposure to the drug in the womb can cause risky behavior in teenage boys.
When developing rats were exposed to THC, the active ingredient of weed, in the womb, their brains made excess dopamine, which could increase their risk of addiction – but it only applied to men, scientists at Cagliari University found
Cannabis is the most commonly used medicine by women of reproductive age – and not just for recreational purposes. A maximum of one in seven takes it during pregnancy.
As legal access grows, it is increasingly used to treat morning sickness and anxiety.
But doctors or other medical staff rarely give advice on the risks for expectant mothers.
The effect on neurons was similar to those previously identified in offspring exposed in the womb to cocaine or alcohol.
& # 39; Because doctors warn pregnant women against alcohol and cocaine intake because of their harmful effects on the fetus, based on our findings, we also advise them on the consequences of using cannabis during pregnancy, & # 39; said Dr. Melis.
Large numbers of children will be exposed to the ingredients in the coming decades – before they are born.
This will happen if the potential risks of parenting are still underestimated and the legalization policy continues.
Rats are often used in research to model the effect of cannabis on humans.
& # 39; Current findings are crucial to unmasking and emphasizing extensive neuro-biological maladaptations that increase the vulnerability of progeny to neuro-psychiatric disorders, & # 39; said Dr. Melis.
Previous research has shown that babies born to mothers who used cannabis while pregnant were experiencing physical activity problems.
Chemicals called cannabinoids can be transmitted from the mother to the offspring through the placental blood.
In the study published in Nature Neuroscience, pregnant rats received daily injections of THC (tetrahydrocannabinol) equivalent to low doses in humans.
When pre-adolescence male offspring was confronted with an unstable bridge, they attempted to cross more often than women – or unexposed peers.
& # 39; They were more inclined to cross the bridge and showed a clearly reduced evaluation of the risk assessment & # 39 ;, said Dr. Melis.
It is a problem that is seen with many psychiatric illnesses. Scans also showed dopamine in the VTA (ventral tegmental area) that is involved in reward and motivation, which were hyperactive.
This is an area in the brain that is known to be involved in reward and motivation, explains Dr. Melis out.
She added: & # 39; Such persistent increased excitability of VTA dopamine neurons is an established neuro developmental risk factor that confers vulnerability to psychiatric disorders.
& # 39; This can manifest difficulties in learning and processing rewards, and provides an interpretative framework for clinical studies that report inappropriate behavior ranging from affective disorder to psychosis and vulnerability to addiction in the offspring of mothers who use cannabis during pregnancy. & # 39;
Her team was able to correct the behavioral and neural changes by treating the adolescent rats with pregnenolone.
This is a drug approved by the US Food and Drug Administration that is currently undergoing clinical trials for cannabis abuse, schizophrenia, autism, and depression.
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