Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

How pregnancy can boost risk of cancer spread

Here's why women who get breast cancer after having a baby are at higher risk of tumour metastasis to the liver than women who have never been pregnant.

Women who get breast cancer within five years of giving birth are at much higher risk than those who have never had children of seeing the tumours spread, or metastasize, to the liver. This could be due to changes in the liver as it readjusts after pregnancy.

In rodents, the liver expands during pregnancy. Virginia Borges at the University of Colorado, Aurora, Pepper Schedin at Oregon Health and Science University in Portland and their colleagues studied the organ in rats and mice. They found that after weaning, the liver shrank and was infiltrated with immune-suppressing white blood cells. Many liver cells died and others secreted proteins that promote wound-healing, providing a fertile ‘soil’ in which tumours can grow.

When the authors injected cancer cells into mice, more liver metastases developed in animals that had just weaned their pups than in those that had never had offspring.

More Research Highlights...

Selected materials found in the gut contents of Tollund Man

The intestinal contents of a man killed in a prehistoric ritual (clockwise from upper left): barley, charred food that had been encrusted in a clay pot, flax seeds and sand. Credit: Peter Steen Henriksen, the Danish National Museum


The guts of a ‘bog body’ reveal sacrificed man’s final meal

Tollund Man, who lived more than 2,000 years ago, ate well before he was hanged.
Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing


Quick links