California mother Maggie Jean Wortmon, 26, faces charges of second-degree murder for breastfeeding.

Evidence at the woman's preliminary hearing suggests that she "knowingly endangered her infant's life by breast-feeding while using methamphetamine," according to ABC News

According to the New York Times, "The baby was pronounced dead at a local hospital, and was later discovered to have methamphetamine in his system."

Drugs, legal or illegal, can have severe consequences for a breastfeeding infant.

According to pregnancy.org there are more than 4 million live births a year in the United States. About 30 percent of mothers breastfeed exclusively through three months, according to the Centers for Disease Control and Prevention.

Marchofdimes.com said, "Nearly 4 percent of pregnant women in the United States use illicit drugs such as marijuana, cocaine, Ecstasy and other amphetamines, and heroin."

The medicine that enters a mother's system while breastfeeding can and does affect the baby. Psychology Today said, "Most medications are safe for breastfeeding, with a few exceptions, such as chemotherapy and radioactive drugs. Doctors will modify medications for breastfeeding mothers, so that their children won't be harmed."

The article goes on to say "more research examining the short- and long-term effects of drugs on breastfeeding infants is needed"

And there are many websites dedicated to giving guidance to breastfeeding mothers. Motherrisk.org offers a list of drugs that are dangerous to take while breastfeeding.

Breastfeeding Basics says that, "As a nursing mother, you should be aware that there are three things we know for sure about drugs and breast milk:

1."Nearly all drugs pass into human milk.

2."Almost all medication appears in very small amounts, usually less than 1 percent of the maternal dose.

3."Very few drugs are contraindicated for nursing mothers."

Methamphetamine, the drug Wortmon allegedly was taking when she breastfed her child, has been proven as extremely dangerous.

"When a mother is using meth, the drug can be passed to the baby through the mother's milk and can be very harmful and potentially lethal. Mothers in this situation should take extra precautions," said Lori Rittel, in an article for mt.gov.

And drugs.com said the effects in breast-fed infants could be fatal. "A 2-month-old infant whose mother used illicit street methamphetamine recreationally by nasal inhalation was found dead 8 hours after a small amount of breastfeeding and ingestion of 120 to 180 mL of formula."