Effects on fertility

Some breast cancer treatments can affect your ability to have children (fertility). For many younger women, this can be a major concern. Having a family can be an important part of moving on with life after cancer. Some women, particularly if they’re younger women, have no difficulties getting pregnant naturally after treatment.

Doctors usually advise that you wait for at least two years after treatment before getting pregnant. This is the time when the cancer is most likely to come back, but it also gives you time to recover from treatment. Pregnancy raises your natural hormone levels so it’s important to talk to your specialist first if you’re planning to get pregnant. Some studies show that pregnancy after breast cancer doesn’t increase the risk of breast cancer coming back. But there hasn’t been a lot of research in this area and more is needed. Your specialist can advise you on the risk of the cancer coming back and how safe pregnancy is in your situation.

Infertility may be temporary or permanent, depending on the treatment you’ve had and on your age. Check with your breast care nurse or cancer specialist if you’re not sure if you need to continue using contraceptives to prevent pregnancy. Women who’ve had breast cancer are advised not to take the contraceptive pill or use coils (IUDs) containing hormones as these could encourage breast cancer cells to grow. Your cancer specialist or specialist nurse will give you more advice about this.

Hormonal therapy

Drugs, such as goserelin, which are used to stop the ovaries from working (known as ovarian suppression) cause temporary infertility. Your periods usually start again about six months after the treatment stops.

Women taking tamoxifen often find that their periods change. Your periods may stop, become less regular, heavier or lighter. If periods stop, they usually start again when you stop taking tamoxifen. Even if your periods stop when taking tamoxifen, it's still possible to become pregnant. Taking tamoxifen can affect an unborn baby, so it isn't safe to become pregnant while taking it.

Tamoxifen is usually prescribed for five years and, depending on your age, this may be an issue if you want to get pregnant. It's important to talk this over with your specialist.

The side effects of hormonal therapy are similar to the effects of menopause. Women in their 40s may go through their menopause without knowing it, while taking hormonal therapy.

Chemotherapy

Chemotherapy affects the way the ovaries work and can result in fewer or no eggs being produced. Cyclophosphamide, which is used in combination with other drugs to treat breast cancer, is the drug most likely to cause infertility.

Some women may go into menopause immediately after treatment, especially if they're close to their natural menopause. If your periods don't come back after some months, your specialist can do blood tests, which may help to indicate if you've gone through the menopause.

If you're in your thirties (particularly under 35), even if your periods stop, they'll usually come back again months or years after treatment has finished. Some young women don't stop having periods at all. The younger you are, the more likely it is that your fertility will be preserved after chemotherapy.

Chemotherapy reduces your egg supply. This means that even though you're having periods, your menopause may start earlier than it would have without cancer treatment. It's important to consider this if you're thinking of having a family.

Referral to a fertility clinic

If you've had chemotherapy and are having difficulty getting pregnant, you can ask your doctor to refer you to a fertility specialist. Women who have had chemotherapy are usually referred after six months of trying to get pregnant because of their risk of early menopause. The fertility specialist will give you advice on the possible options available to you.

There are different ways of becoming a parent. Some women may consider egg donation, surrogacy or adoption. You can read more about these options in our section on fertility.

Women who had an embryo (a fertilised egg) or eggs frozen and stored before treatment can have fertility treatment later on, which may result in a successful pregnancy.

Becoming infertile can be very hard for some women to live with – whether or not they already have children. Some women may find it helpful to talk through their feelings with a trained counsellor. If you need more specialised help, your doctor can arrange this for you.