There is no single cause of depression. There are many reasons why a woman may become depressed:

Hormonal factors - menstrual cycle changes, pregnancy, miscarriage, postpartum period, perimenopause, and menopause
Stress - at work and home, single parenthood, caring for children and for aging parents
Family history - inherited (it's in your genes); it can also occur in people with no family history
Medical illness - stroke, heart attack, cancer
Chemical imbalance - changes in the brain chemistry

What are the signs of depression?

Not all people with depression have the same symptoms. Some people might only have a few, and others a lot. If you have one or more of these symptoms for more than 2 weeks or months at a time, see your doctor.

Feeling sad, anxious, or "empty"
Feeling hopeless
Loss of interest in hobbies and activities that you once enjoyed
Decreased energy
Difficulty staying focused, remembering, making decisions
Sleeplessness, early morning awakening, or oversleeping and not wanting to get up
No desire to eat and weight loss or eating to "feel better" and weight gain
Thoughts of hurting yourself
Thoughts of death or suicide
Easily annoyed, bothered, or angered
Constant physical symptoms that do not get better with treatment, such as headaches, upset stomach, and pain that doesn't go away

What if I have thoughts of hurting myself?

Depression can make you think about hurting yourself or suicide. You may hurt yourself to:

Take away emotional pain and distress
Avoid, distract from, or hold back strong feelings
Try to feel better
Stop a painful memory or thought
Punish yourself
Release or express anger that you're afraid to express to others

You might feel like your pain is too overwhelming to cope with, but those times don't last forever. People do make it through suicidal thoughts. If you can't find someone to talk with, write down your thoughts. Try to remember and write down the things you are grateful for. List the people who are your friends and family, and care for you. Write about your hopes for the future. Read what you have written when you need to remind yourself that your life is IMPORTANT!

Source Steve Valentino