How does having a baby lower the risk of breast cancer in women?

Less cycles. Early menopause, late menarche and first full term pregnancy by age 18 lower the risk of breast cancer. This is apparently done because the number of menstrual cycles is lowered over a woman's life by these factors. This lowers a woman's exposure to endogenous hormones, like estrogen.
Less estrogen. The placenta puts out progesterone, which acts as an estrogen antagonist (off switch) in the body, to prevent ovulation while you're pregnant. The cyclic ramp up in estrogen is also avoided. This period of lower estrogen exposure lowers overall cancer risk.

Related Questions

Am 32 taking combined pills since18months is there risk of breast cancer How many years can I take them safe I have disabled infant cant get pregnant?

What is a combined. pill? Please specify, and resubmit, with further information. You may submit separate questions--one with regard to your infant--has anyone tried to determine the cause of the disability? Another about how long have you been trying to get pregnant? (not a concern if less than 12 months). Please explain why you are concerned about cancer? family history? Read more...

Can breast cancer affect a pregnant woman's baby?

Breast cancer. Breast cancer during pregnancy can cause difficulties in treatments. The cancer itself would not affect the fetus. However decisions on surgery, radiation & some forms of chemotherapy can have an affect on a fetus. Need a very detailed review with a medical oncologist and the obstetrician to coordinate care & review risks and options. Read more...

Is it true that breast cancer grows fast in pregnant women?

Yes. It is masked by the other changes of pregnancy, even if it grows at identical rate! high risk+ family positive would lead to even more careful exams before and during pregnancy. Read more...
Often. The majority of breast cancers are hormone sensitive/dependent. With pregnancy, there are extremely high hormonal levels creating a highly stimulatory environment for a sensitive cancer. This does not mean that everything that changes or appears in the breast is cancer - many benign changes occur in all women and benign lesions cane also appear and grow quickly. Present any concerns to your md. Read more...

Can having a baby or two help me prevent breast cancer?

Yes. Yes . Woman by having children, and by breast feeding them will have lesser incidence of breast cancer, than the woman that did not. Read more...
Weigh the risks. Even if "having a baby or two" were to reduce your risk of breast cancer, there are risk associated with child bearing. You ought to consult your doctor to weigh the relative risks and benefits of your proposed actions. Some might argue that bringing babies into this world for "reducing" your risk of breast cancer is not ethical. Read more...

Had 2 babies over 40. Is that considered high risk for breast cancer? Breastfeed both. How much higher of a risk than average woman.

No. This doesn't increase your risk. Even if it did, it's moot. You did what was right for you. Keep up proper surveillance against breast cancer. I'm old-fashioned and believe in monthly self-exam. Comply with your physician's instructions on mammography. Report any dominant masses to your physician without delay. Do this and your chances of dying of breast cancer are extremely low. Read more...
Minimal if any. We don't truly understand what "causes" breast cancer outside certain mutations (brca1/2) ; in most cases its a combination of factors - gene switches ; lifetime experiences. Many items associated w/ "risk" have been identified such as early menarche, late 1st period, mammo density. These are not causes but likely surrogates for other influencing factors. #1 risk: being female and having breast. Read more...

I'm 28 female and my left breast is heavy aching. I'm not on any tablets or contraception, not pregnant. I'm worried it's breast cancer?

Not likely. It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor. It is less likely to be cancer and an infection is more likely. However, I urge you to see your doctor. Read more...