Does Having Children Increase Your Breast Cancer Risk?

Can Having Children Increase Your Breast Cancer Risk?

Baby-150There’s a growing number of women who choose to have children later on in life. Many of those women have asked us if having children has an effect on breast cancer risk.

According to Dr. Jay Harness, women who have their first birth at the age of 35 or older have an increased risk of developing breast cancer.

Dr. Harness candidly shares that he is concerned about women attempting to have children later on in life. His concern is due to the increased number of in vitro fertilization procedures.

The multiple cycles of in vitro fertilization can potentially overstimulate the breasts and can possibly lead to an increased risk of breast cancer.

In this video, watch Dr. Harness as he discusses how having children affects your breast cancer risk.


Jay K. Harness:  Women are often worried about their biological clock and worried about having children later in life and I am asked a question, does having children later in life increase your risk of breast cancer.  Let me share with you that it is.

In the western societies and certainly in United States, in Europe, in Australia and New Zealand where we have some of the highest incidents of breast cancer in the world and that includes Canada as well, often what we have seen over the past several decades is waiting to have children and obviously later in life being married.  This is very-very common.

Women want to have careers.  They want to have a life.  They want to do things that are meaningful and they are always thinking in the back of their mind, well my biologic clock is ticking, but we do know that also ticking is the increased risk for breast cancer.  The data is pretty clear that if you have your first birth at age 35 or older, there is a small increased risk of breast cancer.

We don’t know why.  It may be that the cycling of the breast that the breast goes through a cycling with pregnancy prior to age 35 has some sort of protective effect.

Historically, we have known that women who had their first live birth by age 18 have a lower risk of breast cancer, again not a guarantee, but it appears to have a protective effect and we don’t know why.  The cells that line the inside of the ductal system are being proliferated each month as you go through your normal cycle.

You remember that just before your menstrual period, the breasts feel heavier and potentially more painful and so they are getting ready for pregnancy and if that pregnancy does not happen, they go oh wow and go back to where they were and it may well be that whatever mechanisms are triggered by actually going on the pregnancy are protective in its own way.

Now, we have more-more women having children with in vitro fertilization and women having children in their early 40s and some even in their mid 40s.  I must share with you candidly that I worry about those women a lot.  With in vitro fertilization, there is a great bang if you will, hormones that are given in order to stimulate ovulation or if you are going to have an implant of fertilized egg to make sure that the uterus does not return to.

Many of us in the field are worried about if you have been through IVF several cycles, is that potentially over stimulating the breasts and potentially leading to an increased risk of breast cancer.  I would say in this subject more to be revealed, but the fact of the matter is that having your first born child age 35 or later, there is an increased risk for breast cancer, be more diligent, screen regularly and if this happens, we will at least detect it early.