NEW YORK (CBSNewYork) – If you’ve had a baby, love being a mom and can’t wait to have another, you might want to wait at least a year.

CBS2’s Dr. Max Gomez says a new study finds having kids closer in age may be unhealthy for mother and child.

How long should women wait between pregnancies?

Medical advice varies: The World Health Organization says two years; the American Gynecological Association says at least six months.

Many couples have their own ideas, but now researchers are saying one year is the prime time to wait between the birth of one child and the conception of another to prevent health complications for both mother and baby.

The study published in the JAMA Internal Medicine Journal says the risk of death for women who get pregnant less than 12 months after delivery is higher in women over the age of 35.

The risk of spontaneous preterm delivery – “preemies” – and health risks for the baby are higher for younger mothers with shorter intervals between pregnancies.

Of course there are many good reasons – economic, miscarriages and others – that couples space pregnancies far apart… sometimes very far apart.

Some studies suggest more than five years is also associated with negative outcomes for both mom and baby.

The idea is that this information can help women who are planning their families know the risks, especially now that more women are choosing to delay motherhood due to careers.

The conclusions suggest mothers – especially those over 35 – add a little extra time between pregnancies to protect both mom and baby.

Mother Nature sometimes does her part to help women space their pregnancies if they breast feed.

Consistent and frequent breast feeding has been shown to delay ovulation and fertility although for how long varies greatly, from six weeks to more than eight months.