Having more children may help protect women against risk of developing different types of cancer, researchers reveal.pudgeefeet/Flickr

Having more children may protect women against risk of developing different types of cancer, researchers reveal.

During the study, Dr Juha Tapanainen from the Helsinki University Central Hospital in Finland and colleagues analysed 5,000 Finnish women who had given birth 10 or more times and compared risk of cancer in them to the general population, Livescience reported.

Of the total women studied, nearly 656 developed cancer. On the other hand, additional 200 cases were reported in the general Finnish population. Giving birth 10 times or more was associated with 24 percent lowered risk of all kinds of cancers.  

Interestingly, risk of breast and gynaecological cancers - ovarian and endometrial cancers - were nearly halved in women who had 10 or more children. Multiple births were also associated with a lowered risk of basal cell skin cancer, but an increased risk of thyroid cancer.  

The lowered cancer risk associated with more babies may be the result of an early pregnancy and birth. Compared to the Finnish general population, women who had 10 babies were nearly five years younger when they had their first baby, Dr Tapanainen said.

The theory supports views of experts from the National Cancer Institute in the US. Increased number of births and pregnancy at an early age can help protect against breast cancer, according to them.  

Full-time pregnancy before age 20 or giving birth five or more times halved risk of breast cancer compared to pregnancy after 30, and women who never gave birth.

They said that certain factors that increase the length or level of exposure to ovarian hormones stimulates cell growth, thus increase risk of breast cancer.

Early menarche (when a girl's menstrual periods starts), delayed menopause, delayed first pregnancy or not giving birth are some other factors known to influence the hormone exposure. 

Additionally, there exists solid evidence to show that longer duration of breastfeeding can decrease risk of breast cancer and that giving birth to last child after age 30 reduces risk of endometrial cancer. 

(Edited by Anu James)