But up to 80-percent of new mothers experience some sort of postpartum blues.

New research may explain why.

Scientists at the Medical College of Georgia believe the baby blues are linked to the blood flow between a mother's blood and her fetus.

While in the womb, the placenta controls the exchange of nutrients and oxygen from mother to child.

But after birth, blood continues to flow from the mother's uterine artery, causing serotonin, a hormone linked to depression, levels to rise.

This in turn triggers production of another chemical which creates even more unneeded serotonin.

Researchers say until these levels normalize, moms get the blues.

While medications that would lower hormone levels may help mothers fight depression, they could transfer in breast milk, possibly causing problems for the baby.

In other medical news…

Common moisturizers may increase the risk for skin cancer, according to experts from Rutgers University.

Researchers there were trying to study the effects of caffeine on skin cancer. They were searching for ways to deliver caffeine to the skin, and in the process looked at several common moisturizers.

They exposed hairless mice to UV rays for 20 weeks, then applied moisturizers to their skin once a day, five days a week, for 17 weeks.

They found the mice given the moisturizer had an average 70 percent increase in the production of skin cancer tumors.

While the researchers were surprised with the results, but they are not saying people should stop using moisturizer.

They say lotion has a medical benefit by preventing breaks in dry skin, and they don't know if these results apply to humans.

The types of skin cancer that developed were not melanoma, the most dangerous form of the disease.
For many women, there is no greater experience than giving birth to a child.