News | Study Finds Cannabis Component THC May Harm Egg Quality and Embryo Health
A study suggests that tetrahydrocannabinol (THC), the main active component of cannabis, may accelerate oocyte maturation while significantly increasing chromosome-segregation errors and spindle abnormalities. This could reduce the rate of chromosomally normal embryos and is relevant to women planning in vitro fertilization (IVF). The findings were published in Nature Communications.
As cannabis use rises worldwide and THC concentrations increase from about 3% in the 1980s to 30% today, concern about potential reproductive risks for women is growing. Extensive evidence already shows that THC can affect male fertility, including sperm DNA methylation, count, and morphology, but its direct effects on female oocytes remain poorly understood.
The study combined in vitro experiments with a retrospective case-control analysis. Using follicular fluid and immature oocytes donated by IVF patients, researchers evaluated gene expression, chromosome segregation, and spindle morphology after THC exposure. To maintain sample quality, they excluded participants of advanced age, those with poor previous reproductive outcomes, and those known to use cannabis.
THC and its metabolites were found in about 6% of tested follicular-fluid samples, and 73% of positive patients had not reported cannabis use. Metabolite concentrations were positively associated with oocyte maturation, but not clearly associated with fertilization or blastocyst formation rates.
Both low-dose THC, near physiological levels, and high-dose THC caused marked changes in oocyte gene transcription involving inflammation, extracellular matrix remodeling, immune signaling, and chromosome segregation. With high-dose exposure, 92% of oocytes had abnormal spindles, compared with 42% of controls, and complex aneuploidy rose significantly (42% vs 0%).
Clinically, patients who tested positive for THC had significantly lower embryo euploidy rates and were less likely to produce high-quality blastocysts than matched controls. Fertilization and blastocyst formation did not differ significantly in unadjusted comparisons, but after multivariable adjustment, THC exposure was closely associated with reduced likelihood of obtaining high-quality embryos.
The researchers emphasized that oocytes are highly sensitive to environmental exposures. THC-related disruption of maturation and genetic stability may affect reproductive outcomes and potentially the health of the next generation. People planning assisted reproduction should carefully assess cannabis-use risks and receive thorough counseling before treatment.
The study’s strengths include combining clinical data with cell experiments and directly measuring THC metabolites in follicular fluid rather than relying on self-report. The authors recommend further research into dose-response relationships, mechanisms, and long-term embryonic development.
News | Study Finds Cannabis Component THC May Harm Egg Quality and Embryo Health
News | Study Finds Cannabis Component THC May Harm Egg Quality and Embryo Health
A study suggests that tetrahydrocannabinol (THC), the main active component of cannabis, may accelerate oocyte maturation while significantly increasing chromosome-segregation errors and spindle abnormalities. This could reduce the rate of chromosomally normal embryos and is relevant to women planning in vitro fertilization (IVF). The findings were published in Nature Communications.
As cannabis use rises worldwide and THC concentrations increase from about 3% in the 1980s to 30% today, concern about potential reproductive risks for women is growing. Extensive evidence already shows that THC can affect male fertility, including sperm DNA methylation, count, and morphology, but its direct effects on female oocytes remain poorly understood.
The study combined in vitro experiments with a retrospective case-control analysis. Using follicular fluid and immature oocytes donated by IVF patients, researchers evaluated gene expression, chromosome segregation, and spindle morphology after THC exposure. To maintain sample quality, they excluded participants of advanced age, those with poor previous reproductive outcomes, and those known to use cannabis.
THC and its metabolites were found in about 6% of tested follicular-fluid samples, and 73% of positive patients had not reported cannabis use. Metabolite concentrations were positively associated with oocyte maturation, but not clearly associated with fertilization or blastocyst formation rates.
Both low-dose THC, near physiological levels, and high-dose THC caused marked changes in oocyte gene transcription involving inflammation, extracellular matrix remodeling, immune signaling, and chromosome segregation. With high-dose exposure, 92% of oocytes had abnormal spindles, compared with 42% of controls, and complex aneuploidy rose significantly (42% vs 0%).
Clinically, patients who tested positive for THC had significantly lower embryo euploidy rates and were less likely to produce high-quality blastocysts than matched controls. Fertilization and blastocyst formation did not differ significantly in unadjusted comparisons, but after multivariable adjustment, THC exposure was closely associated with reduced likelihood of obtaining high-quality embryos.
The researchers emphasized that oocytes are highly sensitive to environmental exposures. THC-related disruption of maturation and genetic stability may affect reproductive outcomes and potentially the health of the next generation. People planning assisted reproduction should carefully assess cannabis-use risks and receive thorough counseling before treatment.
The study’s strengths include combining clinical data with cell experiments and directly measuring THC metabolites in follicular fluid rather than relying on self-report. The authors recommend further research into dose-response relationships, mechanisms, and long-term embryonic development.
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Collected online