The goal of the study is to define and measure biological processes that contribute to the underlying pathophysiologic process of peri-partum depression to be used for identifying those at risk for developing it. This knowledge may also generate novel drug targets for peripartum depression that may be applicable to other types of depression.

This study analyses the role of inflammation and metabolites of inflammation in perinatal depression. Psychiatric assessments of depression and suicidality will be compared to blood levels of two metabolites of inflammation, quinolinic acid (QUIN) and picolinic acid (PIC), that might regulate nerve cell communication. The levels of these metabolites are regulated by kynurenine pathway enzymes.

Psychiatric symptoms, inflammatory cytokines and levels of the metabolites will be measured throughout pregnancy. Additionally, the investigators are gathering placentas at delivery and determining the degree of inflammation in the tissue in the investigators' laboratory. Inflammatory biomarkers, antibody titers, and key kynurenine pathway enzymes and metabolites from pre- and post partum women, placenta, and cord blood will be measured.

Inclusion Criteria

Pre-partum cohort:

• All races and national origins of pregnant females.
• Age 18 and older.
• English speaking.
• Able to give informed consent.
• Able to comply with study procedures.

Exclusion Criteria

Pre-partum cohort:

• Non-pregnant females
• Patients with psychotic symptoms and/or severe cognitive impairment that interfere with their ability to give informed consent or to complete study assessments.
• Patients that cannot read and write in English as research measures used have only been validated in English speaking populations.
• Patients that have blood-borne chronic infections including hepatitis B, C, or HIV as established at routine pregnancy blood screens; they will be excluded as the laboratory facilities do not approve processing of their tissue for safety reasons.
• Patients who have any schizophrenia spectrum disorder or bipolar disorder type 1 (based on self report and SCID interview); these patients will be excluded as the neurobiology of these disorders are different from peripartum depression.
• Patients who report ongoing substance abuse or dependence (in the past 3 months).

Inclusion criteria

Post-partum cohort:

• All races and national origins of females who delivered a child vaginally or by caesarian section up to 6 months prior to enrollment.
• Age 18 and older.
• Edinburgh Perinatal Depression Rating Scale score of 10 and above and/or endorsed suicide ideation on the CSSRS.
• Depressive symptoms which began or worsened (if already present) during pregnancy or up to 4 weeks post-partum.
• Able to give informed consent.
• Able to comply with and complete study procedures.
• English speaking.

Exclusion criteria

Post-partum cohort:

• Patients with psychotic symptoms and/or severe cognitive impairment that interfere with their ability to give informed consent or to complete study assessments.
• Patients who cannot read and write in English as research measures used have only been validated in English speaking populations.
• Patients that have blood-borne chronic infections including hepatitis B, C, or HIV; as established at their routine pregnancy blood screens.
• Patients who have any schizophrenia spectrum disorder or bipolar type 1 (based on the self report and SCID interview).
• Patients who report ongoing substance abuse or dependence (past 3 months).

Pregnant females age 18 and older, psychiatrically healthy or depressed; post-partum females experiencing perinatal depression with and without suicide ideation.