Antenatal depression, also known as prenatal or perinatal depression, is a form of clinical depression that can affect a woman during pregnancy, and can be a precursor to postpartum depression if not properly treated. It is estimated that 7% to 20% of pregnant women are affected by this condition. Any form of prenatal stress felt by the mother can have negative effects on various aspects of fetal development, which can cause harm to the mother and child. Even after birth, a child born from a depressed or stressed mother feels the affects. The child is less active and can also experience emotional distress. Antenatal depression can be caused by the stress and worry that pregnancy can bring, but at a more severe level. Other triggers include unplanned pregnancy, difficulty becoming pregnant, history of abuse, and economic or family situations.Commonly, symptoms involve how the patient views herself, how she feels about going through such a life changing event, the restrictions on the mothers lifestyle that motherhood will place, or how the partner or family feel about the baby. Pregnancy places significant strain on a womans body, so stress, mood swings, sadness, irritability, pain, and memory changes are to be expected. Left untreated, antenatal depression can be extremely dangerous for the health of the mother and the baby. It is highly recommended that mothers who feel they are experiencing antenatal depression have a discussion about it with their health care provider.
Often it is associated with the fear and stress of the pregnancy. Other factors include unintended pregnancy, hyperemesis gravidarum, financial issues, living arrangements and relationships with the father and family. Typically, depression symptoms associated with pregnancy are categorized as postnatal depression, due to the onset of symptoms occurring after childbirth has occurred. The following is a breakdown of when a group of various women began to feel the onset of symptoms associated with depression:

11.8 percent at 18 weeks
13.5 percent at 32 weeks
9.1 percent 8 weeks after the birth
8.1 percent 8 months after the birthIn a recent article posted by The BabyCenter, the authors stated that "For years, experts mistakenly believed that pregnancy hormones protected against depression, leaving women more vulnerable to the illness only after the baby was born and their hormone levels plunged." This is a possible explanation as to why antenatal depression has just recently been identified. Prevalence and causes
The prevalence of antenatal depression differs slightly by region of world. In the United States, antenatal depression is experienced in as many as 16% of pregnant women, while in South Asia it is experienced in as many as 24% of pregnant women. Its becoming more prevalent as more medical studies are being done. Antenatal depression was once thought to simply be the normal stress associated with any pregnancy, and was waved off as a common ailment. It can be caused by many factors, usually though involving aspects of the mothers personal life, such as family, economic standing, relationship status, etc.