The substances a mother puts in her body during pregnancy nearly always reach her developing baby. The long-term effects of illegal drugs can often present problems for these children.

Alcohol and pregnancy don't mix. And neither does alcoholism and a baby's first year of life. Mothers who don't have alcohol problems are much more likely to see their babies grow up.

The dangers of secondhand smoke for children can often show up in unexpected ways. Even some bacterial illnesses can pose a higher risk to children if they're around secondhand smoke.

So it's pretty clear that smoking while pregnant is a bad idea. But what if it's just those around you who are smoking? Does that affect unborn babies too? Possibly.

It's challenging enough to raise headstrong toddlers. But toddlers and older kids whose mothers used cocaine during pregnancy? Their behavior can be especially difficult.

It's clear that heavy drinking while pregnant can harm a baby. But research has been less clear about whether only a few drinks makes a difference. Until now.

Most women know they are advised not to drink during pregnancy. They may not realize how much drinking while pregnant can deeply affect children's brains even years later.

Many factors influence individuals' weight. The same is true for children. Preventing obesity is easier when we know what factors increase a baby's risk of becoming overweight.

There are 101 reasons not to smoke while you're pregnant. But here is reason #102: there's some evidence it might change the way your child's brain works later on.

It's pretty well established that smoking while pregnant leads to various negative health effects for your child. But even being around cigarette smoke can affect your unborn baby.