The savage dismembering of a Texas baby allegedly by his own mother this past Sunday is the most recent example of why new mothers need to be carefully monitored by their physicians during and after their pregnancies, doctors say.

Although it only makes the news when a new mother harms her child or children — think Andrea Yates — due to postpartum depression, the truth is, said one doctor, there are also many cases where new mothers harm, even kill, themselves in the months after giving birth to a child.

“All obstetrical doctors that deliver babies need to do pre- and post-natal assessments of new mothers,” said Dr. Manny Alvarez, managing editor of health for FOXNews.com. “This is a real disease. It affects 15-20 percent of all pregnant women. And it’s not only dangerous for the child, but also for the mother.”

Authorities say Otty Sanchez, of San Antonio, Texas, dismembered her newborn son and ate some of his body parts before stabbing herself during a grisly rampage.

Police say Sanchez told them she "didn't mean to kill her child" and that the devil made her do it.

Scott W. Buchholz, the infant's father, said Sanchez suffered from postpartum depression and that she told him she was schizophrenic a week before the slaying. Buchholz, who said he is also schizophrenic, said he wants her to receive the death penalty.

A family member has said Sanchez had been undergoing psychiatric treatment and that a hospital called looking for her several months ago. Gloria Sanchez, the mother's aunt, said her niece had been "in and out of a psychiatric ward."

Sanchez has been charged with capital murder and is being held on $1 million bond. Bucholz wants Sanchez to get the death penalty.

Having a history of mental illness puts women at an increased risk for postpartum depression. The reported events surrounding the Sanchez case, if proven true, could point to an even more severe form of postpartum depression called postpartum psychosis in which women hallucinate, hearing voices that aren't there.

“Postpartum depression is common enough that any obstetrician or pediatrician should be alert to the signs of that condition developing in new mothers, particularly in any new mother with a history of affective illness including major depression or bipolar disorder, said Dr. Keith Ablow, a psychiatrist and FOX News Channel contributor. “One of the reasons is that people with depression or bipolar disorder become delusional and come to have fixed beliefs about the world around them, which can include bizarre thoughts about their babies.”

Currently, a number of states require doctors to screen mothers for postpartum depression, including the state of New Jersey, where Alvarez is chairman of the Department of Obstetrics & Gynecology at Hackensack University Medical Center.

“In New Jersey, if you’re not assessing mothers both during and after pregnancy for postpartum depression, then you’re breaking the law,” he said. “And there’s a group, Postpartum Support International, that’s working to get Congress to pass legislation to make it a national law.”

Ablow said it wouldn’t be a bad idea for maternity wards to give new mothers a diagnostic test before they are discharged to assess whether they are starting to feel the effects of postpartum depression. However, the condition can set in at any point after giving birth, said Ablow, adding that some women don’t feel depressed until several months after their baby is born.

Ablow said it is important for women who have a history of depression – or women experiencing it for the first time – not to dismiss medication just because they are pregnant or breast-feeding.

“There are several helpful medicines you can take while you are pregnant and breast-feeding for depression, including some of the antidepressants,” Ablow said. “Not every woman needs to be taken off medication if she is depressed and pregnant.”

Alvarez, who recorded a government public service announcement in Spanish on the dangers of postpartum depression, said the signs of this disease can be subtle, which is why doctors should be aware of patients’ risk factors for the disease including previous mental health problems.

Other risk factors include having previously suffered postpartum depression, being pregnant with multiples, having medical problems such as hypertension and diabetes, and having suffered the previous loss of a child including miscarriages.”

Ablow said the following questions should be asked:

— Have you experienced a change in mood?

— Has your sleep or appetite changed?

— Do you have suicidal thoughts?

— Do you have peculiar thoughts about the baby?

— Have you become hopeless or lost interest in your daily activities?

Alvarez added, “You need to ask questions like ‘Do you feel sad?’ ‘Are you having difficulties?’ And if you’re patient says, ‘Yes I’m having a terrible time,’ you need to intervene.”

Alvarez said intervention can include putting moms in touch with psychologists and psychiatrists that specialize in postpartum depression, giving them information on support groups and emergency call centers and using medication to control symptoms when necessary.