News | Study links assisted reproduction to small increases in some cancer risks, while overall risk remains close to the general population
A large study of more than 400,000 women found slightly higher rates of certain cancers among women who received medically assisted reproduction, particularly uterine and ovarian cancer. However, the increase was generally small, and overall cancer incidence remained broadly similar to that of the general female population.
The findings were published in JAMA Network Open.
Assisted reproductive treatment is increasingly common in developed countries
Medically assisted reproduction (MAR) is becoming increasingly common in many high-income countries. In Australia, about 6.7% of babies born in 2017 were conceived through assisted reproductive treatment.
MAR includes several treatments, such as:
Assisted reproductive technology (ART), including in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI)
Intrauterine insemination (IUI)
Medication-induced ovulation, such as clomiphene citrate
These treatments often involve hormones or repeated puncture of ovarian follicles to retrieve eggs, factors that could theoretically be associated with cancer.
Researchers noted, however, that cancer risk among assisted reproduction patients is not determined by treatment alone. It may also be influenced by reproductive history, hormonal contraceptive use, infertility-related conditions such as endometriosis or polycystic ovary syndrome, and genetic susceptibility.
Protective factors may also be present: women undergoing assisted reproduction generally have lower smoking rates, higher socioeconomic status, and more frequent medical monitoring during treatment.
Study includes more than 410,000 women
This population-based cohort study included 417,984 Australian women who had received assisted reproductive treatment. Participants were ages 18 to 55.
Researchers used administrative databases and registries to collect information on treatment type, pregnancies, cancer diagnoses, and deaths.
Participants were divided into three cohorts by treatment type:
ART group: 274,676 women (65.7%), median age 34 at first treatment
IUI with ovarian stimulation group (IUI/OS): 120,739 women (28.9%), median age 34
Clomiphene ovulation induction group: 175,510 women (42.0%), median age 32
Some women received multiple treatments and could belong to more than one cohort. Most lived in major cities and were seeking treatment for their first child.
The team compared cancer incidence in these women with the general female population, accounting for factors such as age, residential area, and year.
Slightly higher rates of certain cancers
Overall cancer incidence among women treated with ART or IUI-OS was broadly similar to that in the general female population.
Overall cancer risk was slightly higher in the clomiphene group, by about 4%.
For specific cancers, the study found higher rates among women who underwent assisted reproduction, including:
Uterine cancer
Ovarian cancer
Cutaneous melanoma
Breast carcinoma in situ
Uterine cancer risk was elevated in all treatment groups:
About 23% higher in the ART group
About 32% higher in the IUI-OS group
About 83% higher in the clomiphene group
Most additional cases were type I endometrioid cancer.
In the clomiphene group, risk was highest among women ages 18 to 35 and during the first year after treatment. No clear increase was found among women who had given birth before using clomiphene.
Ovarian cancer risk also increased
Ovarian cancer rates were also higher among women treated with ART and IUI-OS:
About 23% higher in the ART group
About 18% higher in the IUI-OS group
Additional cases were mainly endometrioid and serous ovarian cancers.
Risk was highest during the first year after treatment and among women who underwent six or more treatment cycles.
Researchers noted that this early increase may partly reflect closer medical monitoring after treatment and earlier cancer detection, rather than a direct effect of treatment.
Reproductive history also affected the pattern:
Ovarian cancer risk was about 48% to 67% higher among women who had not given birth
Risk was about 20% to 37% lower among women who had given birth
Lower risk of some cancers
The study also found lower rates of some cancers among women who underwent assisted reproduction, including:
Cervical cancer (about 39% to 48% lower)
Respiratory tumors (about 30% to 38% lower)
Researchers believe the lower cervical cancer risk may reflect more frequent screening during infertility assessment, rather than a protective effect of assisted reproduction.
Rates of acute myeloid leukemia, pancreatic cancer, and some urinary tract tumors were also slightly lower.
The absolute increase in risk remains very small
Although risks of some cancers increased, the absolute increases were very small.
Across treatment groups, the increase ranged from fewer than 1 to fewer than 7 cases per 100,000 women per year.
In the clomiphene group, all cancers combined amounted to about 9 additional cases per 100,000 women per year.
Findings support longer-term follow-up
The authors said the findings suggest that personalized risk management and long-term follow-up could be considered for women receiving assisted reproductive treatment.
For example, some cancer risks may be reduced through weight management, limiting sun exposure, and smoking cessation.
Researchers emphasized that this observational study cannot determine whether assisted reproductive treatment directly causes increased cancer risk. Some differences may be related to infertility itself or associated conditions.
Follow-up was also relatively short, and many participants had not yet reached the ages at which cancer is most common. Longer-term studies are therefore needed.
News | Study links assisted reproduction to small increases in some cancer risks, while overall risk remains close to the general population
News | Study links assisted reproduction to small increases in some cancer risks, while overall risk remains close to the general population
A large study of more than 400,000 women found slightly higher rates of certain cancers among women who received medically assisted reproduction, particularly uterine and ovarian cancer. However, the increase was generally small, and overall cancer incidence remained broadly similar to that of the general female population.
The findings were published in JAMA Network Open.
Assisted reproductive treatment is increasingly common in developed countries
Medically assisted reproduction (MAR) is becoming increasingly common in many high-income countries. In Australia, about 6.7% of babies born in 2017 were conceived through assisted reproductive treatment.
MAR includes several treatments, such as:
Assisted reproductive technology (ART), including in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI)
Intrauterine insemination (IUI)
Medication-induced ovulation, such as clomiphene citrate
These treatments often involve hormones or repeated puncture of ovarian follicles to retrieve eggs, factors that could theoretically be associated with cancer.
Researchers noted, however, that cancer risk among assisted reproduction patients is not determined by treatment alone. It may also be influenced by reproductive history, hormonal contraceptive use, infertility-related conditions such as endometriosis or polycystic ovary syndrome, and genetic susceptibility.
Protective factors may also be present: women undergoing assisted reproduction generally have lower smoking rates, higher socioeconomic status, and more frequent medical monitoring during treatment.
Study includes more than 410,000 women
This population-based cohort study included 417,984 Australian women who had received assisted reproductive treatment. Participants were ages 18 to 55.
Researchers used administrative databases and registries to collect information on treatment type, pregnancies, cancer diagnoses, and deaths.
Participants were divided into three cohorts by treatment type:
ART group: 274,676 women (65.7%), median age 34 at first treatment
IUI with ovarian stimulation group (IUI/OS): 120,739 women (28.9%), median age 34
Clomiphene ovulation induction group: 175,510 women (42.0%), median age 32
Some women received multiple treatments and could belong to more than one cohort. Most lived in major cities and were seeking treatment for their first child.
The team compared cancer incidence in these women with the general female population, accounting for factors such as age, residential area, and year.
Slightly higher rates of certain cancers
Overall cancer incidence among women treated with ART or IUI-OS was broadly similar to that in the general female population.
Overall cancer risk was slightly higher in the clomiphene group, by about 4%.
For specific cancers, the study found higher rates among women who underwent assisted reproduction, including:
Uterine cancer
Ovarian cancer
Cutaneous melanoma
Breast carcinoma in situ
Uterine cancer risk was elevated in all treatment groups:
About 23% higher in the ART group
About 32% higher in the IUI-OS group
About 83% higher in the clomiphene group
Most additional cases were type I endometrioid cancer.
In the clomiphene group, risk was highest among women ages 18 to 35 and during the first year after treatment. No clear increase was found among women who had given birth before using clomiphene.
Ovarian cancer risk also increased
Ovarian cancer rates were also higher among women treated with ART and IUI-OS:
About 23% higher in the ART group
About 18% higher in the IUI-OS group
Additional cases were mainly endometrioid and serous ovarian cancers.
Risk was highest during the first year after treatment and among women who underwent six or more treatment cycles.
Researchers noted that this early increase may partly reflect closer medical monitoring after treatment and earlier cancer detection, rather than a direct effect of treatment.
Reproductive history also affected the pattern:
Ovarian cancer risk was about 48% to 67% higher among women who had not given birth
Risk was about 20% to 37% lower among women who had given birth
Lower risk of some cancers
The study also found lower rates of some cancers among women who underwent assisted reproduction, including:
Cervical cancer (about 39% to 48% lower)
Respiratory tumors (about 30% to 38% lower)
Researchers believe the lower cervical cancer risk may reflect more frequent screening during infertility assessment, rather than a protective effect of assisted reproduction.
Rates of acute myeloid leukemia, pancreatic cancer, and some urinary tract tumors were also slightly lower.
The absolute increase in risk remains very small
Although risks of some cancers increased, the absolute increases were very small.
Across treatment groups, the increase ranged from fewer than 1 to fewer than 7 cases per 100,000 women per year.
In the clomiphene group, all cancers combined amounted to about 9 additional cases per 100,000 women per year.
Findings support longer-term follow-up
The authors said the findings suggest that personalized risk management and long-term follow-up could be considered for women receiving assisted reproductive treatment.
For example, some cancer risks may be reduced through weight management, limiting sun exposure, and smoking cessation.
Researchers emphasized that this observational study cannot determine whether assisted reproductive treatment directly causes increased cancer risk. Some differences may be related to infertility itself or associated conditions.
Follow-up was also relatively short, and many participants had not yet reached the ages at which cancer is most common. Longer-term studies are therefore needed.
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Collected online