Trastuzumab emtansine, fertility, menopause and sexual health

Trastuzumab emtansine, also called T-DM1 or Kadcyla, has not been studied specifically for its effect on fertility in people, so no one can say precisely how it affects your ability to have children later. Its chemotherapy payload could, in theory, affect the ovaries or sperm, although it is generally thought to be less damaging to fertility than the chemotherapy many people receive before it. In practice, most people on T-DM1 have already had chemotherapy, and that earlier treatment, together with age and any hormone therapy, usually has a bigger effect on periods, menopause and fertility. What is clear is that T-DM1 can harm an unborn baby. You must not become pregnant during treatment, and the product information advises reliable contraception for seven months after the last dose. Men having T-DM1 whose partner could become pregnant should also use contraception. Breastfeeding is not advised during treatment or for seven months afterwards. If your cancer is hormone receptor-positive, non-hormonal contraception such as a copper coil or condoms is usually recommended. Sexual health matters too. Tiredness, low mood, body changes after surgery and vaginal dryness from hormone therapy or early menopause can all affect intimacy, and there is practical help available. If you hope to have children in future, raise it with your team as early as possible so they can explain your options and timing.

Fertility effects are not fully known

Earlier chemotherapy and age usually matter more, but T-DM1 may add some effect.

Pregnancy must be avoided

Use reliable contraception during treatment and for seven months after the last dose.

Intimacy can be supported

Dryness, tiredness and body image changes are common, and help is available.

This is an area where firm answers are limited, and it is better to know that from the start.

There is little direct data

Trials of T-DM1 did not measure fertility in detail, so advice is based on how the medicine works, animal studies and experience with similar treatments.

Timing matters more than the medicine

If your cancer is hormone receptor-positive, years of hormone therapy may follow, and fertility naturally declines with age during that time.

Periods returning does not settle the question

Some people get periods back but still find conception difficult, while others conceive unexpectedly.

What this page cannot tell you

It cannot predict your personal fertility or say when pregnancy would be safe for you. That needs your oncologist and a fertility specialist together.

Changes in desire and comfort are very common during and after breast cancer treatment. They are a normal part of treatment, not a personal failing.

Ease dryness

Regular non-hormonal vaginal moisturisers and water-based or silicone lubricants can make sex more comfortable. Ask before using any hormonal cream.

Plan around tiredness

Energy is often lowest in the days after each infusion, so closeness may be easier later in the cycle.

Talk openly

Sharing worries with your partner, and with your nurse or a counsellor, can relieve pressure. Physical closeness without sex still counts.