Twins and breast cancer

Ratbag7 · 2025-10-19T10:41:51+00:00

I know quite a few people around where I live who have had both breast cancer and had twins, including myself. Does anyone know if there is a correlation or is it just a coincidence?

Flutterbees · 19/10/2025 12:02

I’ve never heard of this before and I’m very involved in my local twin community. I’m an identical twin. My twin sister had breast cancer 10 years ago. She has three children, no twins. I have identical twins, no breast cancer (although I did have ovarian cancer). Maybe there are hormonal differences from gestating two babies at once, I don’t know. I’ve not heard of any link before though.

mindutopia · 19/10/2025 13:39

I’ve had a look in the medical literature and interestingly, across the board, having a twin (or other multiple) birth is highly protective in terms of breast cancer risk. Women who had multiple births had a significantly reduced risk of breast cancer, hypothesised to be due to elevated levels of pregnancy hormones.

archpublichealth.biomedcentral.com/articles/10.1186/s13690-023-01089-0

FavouritePJs · 19/10/2025 14:57

Flutterbees · 19/10/2025 12:02

I’ve never heard of this before and I’m very involved in my local twin community. I’m an identical twin. My twin sister had breast cancer 10 years ago. She has three children, no twins. I have identical twins, no breast cancer (although I did have ovarian cancer). Maybe there are hormonal differences from gestating two babies at once, I don’t know. I’ve not heard of any link before though.

My mum had ovarian cancer, her twin brother brain cancer and I had breast cancer. We had to undergo genetic testing for a gene mutation as were told that there was a link for all the three of these cancers (depends on the type of brain cancer I believe). Turns outs we had no gene mutation and had just been unlucky.

Flutterbees · 22/10/2025 13:43

FavouritePJs · 19/10/2025 14:57

My mum had ovarian cancer, her twin brother brain cancer and I had breast cancer. We had to undergo genetic testing for a gene mutation as were told that there was a link for all the three of these cancers (depends on the type of brain cancer I believe). Turns outs we had no gene mutation and had just been unlucky.

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We have a very significant family history of gynaecological cancers going back several generations. We had genetic testing done and nothing was discovered. The Dr said we likely have a gene defect which was causing the cancers but which hadn’t been identified by the scientific community.