Is there any way to prevent milk from forming while pregnant ?

the simple answer is no..
actually there is but the answer would be "do not get pregnant!"..
the hormones that help developing the womb in a pregnancy are very the same that help developing the breasts for lactation..

you cannot exert changes on the breasts during a pregnancy without producing ripple effects on the entire body..

you may get some ill-advised answers like dieting when pregnant but this would put the unborn child into serious health risks for low birth-weights and for serious birth defects (and i have seen enough birth defects to feel uneasy about your question)..

the right amount of dieting can easily lead to low birth weight and premature birth, miscarriage and to a dead baby at birth..

so the simple answer is no, there isn't a way EXCEPT by not getting pregnant.. and if you allow me some trolling here, you probably should not be pregnant if you value the shape of your body more than the health of a baby of your own..

probably consider adoption?..

all the best..

You can't take birth control pills while pregnant. You can't take any hormones at all without jeopardizing your pregnancy.

No, if you get pregnant the body will produce milk, and your breasts will increase in size, after you give birth you can get medication to dry up your milk, and your breasts will return to their normal size.

NO.

There's no way to stop that process except to not get pregnant.

If you dont breast feed your milk supply will dry up

While breast milk is much better than formula at bringing blood sugar to normal levels, there may not be enough milk in the breast to boost the newborn baby's blood sugar levels.

Breast milk doesn't form while you're still pregnant. Breast milk forms AFTER you give birth.
If you don't want to develop breast milk, there are tablets that you can ask your doctor to prescribe, that will suppress breast milk from ever developing. You begin taking them immediately after you give birth, and continue taking one tablet a day for about a week thereafter. You don't have to bind your breasts or anything like that - just take the tablets.

Those tablets used to be routinely prescribed for new mothers to take, back in the days before breast feeding once again became the 'in" thing to do.

get a mastectomy

Kayleen is right; the answer is very simple and there was no need for the super long answer the other person gave.

Just don’t breast feed! Your milk supply will dry up. Sadly this won’t stop your breasts from getting bigger initially, but st least they’ll shrink down some after your milk disappears. But it’s not that simple; your breasts can’t get ANY stimulation. You’d have to be careful in the shower, during sex (nipple stimulation), with certain clothes, etc. anything that could cause you to express milk.