Children of mothers who smoke or vape cannabis during pregnancy are more likely to develop stress and anxiety, warns new research.
They are also prone to aggressive behavior and hyperactivity, say scientists.
The discovery adds to evidence marijuana can harm a baby's development in the womb.
It is the most widely taken drug by women of reproductive age - often to relieve stress and anxiety.
Cannabis use among pregnant women has become more common, doubling over the last two decades.
Senior author Dr, Yasmin Hurd, director of the Addiction Institute at Mount Sinai, New York, said: "Pregnant women are being bombarded with misinformation that cannabis is of no risk.
"The reality is it's more potent today than it was even a few years ago. Our findings indicate using it during pregnancy can have long-term impacts on children."
They were based on 322 mother-child pairs in New York City drawn from a study of stress in pregnancy that has been ongoing since 2009.
When they were about six, children whose mothers used cannabis during pregnancy showed higher anxiety, aggression and hyperactivity.
They also had higher levels of the stress hormone cortisol - compared to children of non-cannabis users.
Maternal cannabis use was also linked with poorer heart rate variability, the change in time between heartbeats - reflecting increased sensitivity to stress.
Analysis of placental tissue collected at the time of birth also identified fewer immune-activating genes - predicting higher anxiety.
Cannabinoids, the active agents in cannabis, can be transferred from the mother to the offspring through the placental blood.
First author Professor Yoko Nomura, of the City University of New York, said: "We know cannabinoid signalling plays a role in modulating stress, which is why some people use cannabis to reduce anxiety and relax.
"But our study shows exposure to cannabis in the womb has the opposite effect on children.
"It causes them to have increased levels of anxiety, aggression and hyperactivity compared to other children who were not exposed to cannabis during pregnancy."
Hormone levels, including cortisol released during stress, were measured via the children's hair samples.
Heart function was measured using electrocardiogram recordings as they were subjected to minor stress.
A burst of startling loud tones interrupted their viewing of a calm video as they sat with their parents.
Behavioral and emotional functioning was also assessed based on surveys administered to the parents.
Legalization of cannabis is spreading across the world. Many people "mistakenly believe" its use is without significant health risks.
In line with softening public opinion, it has emerged as one of the most consumed recreational drugs of abuse during pregnancy.
Yet the impact of maternal cannabis use on foetal and childhood development is not clear, said the researchers.
Hurd said: "The study results underscore the need for non-biased education and outreach to the public and particularly vulnerable populations of pregnant women regarding the potential impact of cannabis use.
"Disseminating this data and accurate information is essential to improving the health of women and their children."
In September, a study of 11,500 US children found those whose mothers took it while pregnant were vulnerable to psychosis and sleep problems.
Earlier this year a study in Canada found exposure to the drug in the womb doubles the risk of autism.
Previous research has suggested exposure to cannabis in the womb causes learning and physical activity difficulties in children.
Brain receptors that trigger the behavioural effects of cannabis have been found to be present in rat brains during prenatal development.
Cannabinoids can be transferred from the mother to the offspring through the placental blood during gestation both in humans and in rodents.
Other studies have indicated cannabis taken during pregnancy affects the cognitive development of the unborn child - particularly memory.
Cannabis use among pregnant women has doubled over the last two decades.
The UK's National Health Service says: "Cannabis use may affect fertility. Regular or heavy cannabis use has been linked to changes in the female menstrual cycle and lower sperm count, or lower sperm quality in men.
"Using cannabis while pregnant may harm the unborn baby. Cannabis smoke contains many of the same harmful chemicals found in cigarette smoke.
"Regularly smoking cannabis with tobacco increases the risk of a baby being born small or premature.
"Cannabis has not been linked to birth defects, but research suggests that using cannabis regularly during pregnancy could affect a baby's brain development as they get older."
Stories and infographics by ‘Talker Research’ are available to download & ready to use. Stories and videos by ‘Talker News’ are managed by SWNS. To license content for editorial or commercial use and to see the full scope of SWNS content, please email [email protected] or submit an inquiry via our contact form.
We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
Cookie
Duration
Description
__hssc
1 hour
HubSpot sets this cookie to keep track of sessions and to determine if HubSpot should increment the session number and timestamps in the __hstc cookie.
__hssrc
session
This cookie is set by Hubspot whenever it changes the session cookie. The __hssrc cookie set to 1 indicates that the user has restarted the browser, and if the cookie does not exist, it is assumed to be a new session.
_GRECAPTCHA
5 months 27 days
Google Recaptcha service sets this cookie to identify bots to protect the website against malicious spam attacks.
cookielawinfo-checkbox-advertisement
1 year
Set by the GDPR Cookie Consent plugin, this cookie records the user consent for the cookies in the "Advertisement" category.
cookielawinfo-checkbox-analytics
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional
11 months
The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
CookieLawInfoConsent
1 year
CookieYes sets this cookie to record the default button state of the corresponding category and the status of CCPA. It works only in coordination with the primary cookie.
ts
1 year 1 month 1 day
PayPal sets this cookie to enable secure transactions through PayPal.
usprivacy
1 year 1 month
This is a consent cookie set by Dailymotion to store the CCPA consent string (mandatory information about an end-user being or not being a California consumer and exercising or not exercising its statutory right).
viewed_cookie_policy
11 months
The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features.
Cookie
Duration
Description
__cf_bm
30 minutes
Cloudflare set the cookie to support Cloudflare Bot Management.
li_gc
5 months 27 days
Linkedin set this cookie for storing visitor's consent regarding using cookies for non-essential purposes.
lidc
1 day
LinkedIn sets the lidc cookie to facilitate data center selection.
UserMatchHistory
1 month
LinkedIn sets this cookie for LinkedIn Ads ID syncing.
v1st
1 year 1 month 1 day
The v1st cookie is set by TripAdvisor to collect details about how visitors use the website, by displaying user reviews, awards and information received on the TripAdvisor community.
Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
Cookie
Duration
Description
_gat
1 minute
Google Universal Analytics sets this cookie to restrain request rate and thus limit data collection on high-traffic sites.
_p_hfp_client_id
less than a minute
Elfsight sets this cookie to implement social platforms on the website and enables the social platforms to track the users by assigning them a specific ID.
dmvk
session
The dmvk cookie is set by Dailymotion to record data of visitor behaviour on the website.
SRM_B
1 year 24 days
Used by Microsoft Advertising as a unique ID for visitors.
Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
Cookie
Duration
Description
__hstc
6 months
Hubspot set this main cookie for tracking visitors. It contains the domain, initial timestamp (first visit), last timestamp (last visit), current timestamp (this visit), and session number (increments for each subsequent session).
_clck
1 year
Microsoft Clarity sets this cookie to retain the browser's Clarity User ID and settings exclusive to that website. This guarantees that actions taken during subsequent visits to the same website will be linked to the same user ID.
_clsk
1 day
Microsoft Clarity sets this cookie to store and consolidate a user's pageviews into a single session recording.
_fbp
3 months
Facebook sets this cookie to display advertisements when either on Facebook or on a digital platform powered by Facebook advertising after visiting the website.
_ga
1 year 1 month 4 days
Google Analytics sets this cookie to calculate visitor, session and campaign data and track site usage for the site's analytics report. The cookie stores information anonymously and assigns a randomly generated number to recognise unique visitors.
_ga_*
1 year 1 month 4 days
Google Analytics sets this cookie to store and count page views.
_gat_gtag_UA_*
1 minute
Google Analytics sets this cookie to store a unique user ID.
_gcl_au
3 months
Google Tag Manager sets the cookie to experiment advertisement efficiency of websites using their services.
_gid
1 day
Google Analytics sets this cookie to store information on how visitors use a website while also creating an analytics report of the website's performance. Some of the collected data includes the number of visitors, their source, and the pages they visit anonymously.
AnalyticsSyncHistory
1 month
Linkedin set this cookie to store information about the time a sync took place with the lms_analytics cookie.
CLID
1 year
Microsoft Clarity set this cookie to store information about how visitors interact with the website. The cookie helps to provide an analysis report. The data collection includes the number of visitors, where they visit the website, and the pages visited.
CONSENT
2 years
YouTube sets this cookie via embedded YouTube videos and registers anonymous statistical data.
hubspotutk
6 months
HubSpot sets this cookie to keep track of the visitors to the website. This cookie is passed to HubSpot on form submission and used when deduplicating contacts.
ln_or
1 day
Linkedin sets this cookie to registers statistical data on users' behaviour on the website for internal analytics.
MR
7 days
This cookie, set by Bing, is used to collect user information for analytics purposes.
SM
session
Microsoft Clarity cookie set this cookie for synchronizing the MUID across Microsoft domains.
Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
Cookie
Duration
Description
ANONCHK
10 minutes
The ANONCHK cookie, set by Bing, is used to store a user's session ID and verify ads' clicks on the Bing search engine. The cookie helps in reporting and personalization as well.
bcookie
1 year
LinkedIn sets this cookie from LinkedIn share buttons and ad tags to recognize browser IDs.
bscookie
1 year
LinkedIn sets this cookie to store performed actions on the website.
fr
3 months
Facebook sets this cookie to show relevant advertisements by tracking user behaviour across the web, on sites with Facebook pixel or Facebook social plugin.
IDE
1 year 24 days 1 minute
Google DoubleClick IDE cookies store information about how the user uses the website to present them with relevant ads according to the user profile.
li_sugr
3 months
LinkedIn sets this cookie to collect user behaviour data to optimise the website and make advertisements on the website more relevant.
muc_ads
1 year 1 month 4 days
Twitter sets this cookie to collect user behaviour and interaction data to optimize the website.
MUID
1 year 24 days
Bing sets this cookie to recognise unique web browsers visiting Microsoft sites. This cookie is used for advertising, site analytics, and other operations.
personalization_id
1 year 1 month 4 days
Twitter sets this cookie to integrate and share features for social media and also store information about how the user uses the website, for tracking and targeting.
test_cookie
15 minutes
doubleclick.net sets this cookie to determine if the user's browser supports cookies.
ttwid
1 year
Tiktok sets this cookie to keep track of user authentication and session information.
VISITOR_INFO1_LIVE
5 months 27 days
YouTube sets this cookie to measure bandwidth, determining whether the user gets the new or old player interface.
VISITOR_PRIVACY_METADATA
6 months
YouTube sets this cookie to store the user's cookie consent state for the current domain.
YSC
session
Youtube sets this cookie to track the views of embedded videos on Youtube pages.
yt-remote-connected-devices
never
YouTube sets this cookie to store the user's video preferences using embedded YouTube videos.
yt-remote-device-id
never
YouTube sets this cookie to store the user's video preferences using embedded YouTube videos.
yt.innertube::nextId
never
YouTube sets this cookie to register a unique ID to store data on what videos from YouTube the user has seen.
yt.innertube::requests
never
YouTube sets this cookie to register a unique ID to store data on what videos from YouTube the user has seen.