The most important biological causes of postpartum depression that happens to the new moms are the hormonal changes or imbalances. There is estrogen and progesterone rise in a woman's body during pregnancy. And after delivery there is fall in these hormones. This makes it difficult for the body to adapt to quick changes in hormone balances. Thus, the result is mood swings, sadness, suicidal thoughts, sleeping problems, weight problems etc. seen in a woman. Imbalance in neurotransmitters like serotonin, dopamine etc. can lead to depression. These chemicals are neurotransmitters which transmit the messages from cells to the cells.

Post delivery, there are changes that naturally take place in the lifestyle of the new mother. There is lack of rest, additional responsibility of the baby, less sleep, job loss, loneliness etc. Such changes often cause postpartum depression in women.

Sometimes chronic pain after delivery or miscarriage might be the cause of postpartum depression.

Withdrawal from smoking and drinking habits which is important during pregnancy and after the birth of the child can be a cause of postpartum depression. In that case, it is important to seek counseling and medical help immediately. Some drug which is prescribed might be the cause of postpartum depression. Thus it is important to report to doctor if you find that you are going through symptoms of postpartum depression.