The first month after a delivery (the post-partum period) is a time of major changes for women. Their hormones and weight are rapidly readjusting. There may be new and stressful changes in relationships with other children, the father of the baby, parents and in-laws, colleagues at work, and friends. Of course, the new baby needs almost constant attention and feeding every two hours, resulting in sleep deprivation. All of these factors can contribute to post-partum mood swings.

If the moodiness only lasts 2 -3 weeks and then goes away, it's commonly called the "baby blues". This natural reaction to stress is experienced by more than half of new mothers.

However, if the feelings of depression or anxiety continue more than three weeks, a more serious condition called post-partum depression may exist. About 10% of women experience significant depression after a pregnancy.

You have a higher chance of post-partum depression if:

• You had mood or anxiety disorders prior to pregnancy, including depression with a previous pregnancy
• You have a close family member who has had depression or anxiety
• Anything particularly stressful happened to you during the pregnancy, including illness, death or illness of a loved one, a difficult or emergency delivery, premature delivery, or illness or abnormality in the baby
• You are in your teens or over age 40
• The pregnancy is unwanted or unplanned
• You currently abuse alcohol, take illegal substances, or smoke -- these are also serious medical health risks for the baby

Most of the symptoms are the same as in major depression. In addition to mood fluctuations, the woman becomes preoccupied with the infant's well-being. The intensity of this varies -- the preoccupation may become delusional. Women who are depressed may feel withdrawn and unconnected to their baby, and can even feel as if they might harm the baby.

The presence of severe or delusional thoughts about the infant are symptoms that need immediate attention. These can be accompanied by psychotic "command hallucinations" to kill the infant or delusions that the infant is possessed.

There is no single test to diagnose post-partum depression. Sometimes depression following pregnancy can be related to other medical conditions. Hypothyroidism, for example, causes symptoms such as fatigue, irritability, and depression. Women with post-partum depression should have a blood test to screen for low thyroid hormones. This condition is easily treated with supplemental hormone. Another clue to this condition can be weight gain or failure to lose weight after pregnancy, despite breast-feeding the baby.

Since post-partum depression is so common, questionnaire screening tests are available. Women with any of the risk factors, or with symptoms of depression, should consider taking such a test to determine if they need treatment.

The treatment for depression after birth often includes medication, therapy, or a combination of both. Fortunately, several anti-depressant medications may be given to breast-feeding mothers.

Once depression is diagnosed, the woman will need to be followed closely for at least six months.

Participation in support groups may be valuable, but should be considered an addition to, not a substitute for, medication or formal psychotherapy. Call (800) 4-A-Child to talk to a counselor or get a referral for local support groups. Also, the National Association of Postpartum Care Services at (800) 45-DOULA can direct you to fee-based local services to give you a rest or stay up with the baby at night.

Medication and therapy are often effective in reducing or eliminating symptoms.

Those with underlying hypothyroidism can be treated by taking a pill form of the hormone. However, the two conditions -- depression and hypothyroidism -- can co-exist and may both require treatment.

If left untreated, post-partum depression can last for months or years. The potential long-term complications are the same as in major depression.

Notify your doctor or pediatrician if your moodiness after pregnancy lasts more than three weeks, especially if you have any of the symptoms of post-partum depression or you have any of the risks for it.

Do not be afraid to seek help immediately if you feel overwhelmed and are afraid that you may hurt your baby.

Many women start experiencing some symptoms of post-partum depression even prior to the birth. There is no reason to wait and "see if they will just go away". Notify your obstetrician or primary care provider immediately.

Having good social support from family, friends, and co-workers probably helps to reduce the seriousness of post-partum depression, but may not prevent it.

Taking screening questionnaires appears to be the best method of finding depression early and treating it.

Those at high risk should be screened both before and after delivery and followed closely with repeated screening, depending on symptoms, for at least four months after the delivery.