The goal of this observational study is to develop a blood test that may be predictive of postpartum depression. This Blood test is investigational and not yet FDA approved. Participants will not receive the results of this blood test.

Up to 500 pregnant women will be recruited for the study from 2 sites. Participants must be age 18 or above with a singleton pregnancy and able to provide written consent in English.

The Objective of this Clinical Trial is to prospectively validate the Enlighten Device test by prospectively determining false/true positive and negative rates. Building off of this, an exploratory objective of this study is to examine clinical factors associated with false positive/negative rates.

This project will address the following Aim:

Aim 1: Prospective collection of true/false positive and negative PPD outcomes through 6 months postpartum.

Primary Hypothesis H1a: 80% or greater of pregnant women who develop PPD by 3 months after delivery will be determined to be Biomarker Positive by the Enlighten Device in T3.

Primary Hypothesis H1b: 10% or fewer of pregnant women who are determined to be Biomarker Negative by the Enlighten Device in T3 will develop PPD by 3 months after delivery.

Exploratory Aim 1: Investigation of clinical factors that may be associated with false positive and false negative rates, such as: medication use, stressful life events, and sociocultural context.

Participants will be screened during the second or third trimester and enrolled during the third trimester, before week 30 weeks of gestation. Participants may self- identify through study advertisements in participating clinics, social media outlets, and community outreach efforts. Enrolled participants will undergo blood collection during their 3rd trimester (~27-30 weeks, a standard pregnancy-related blood collection timepoint) for completion of the Enlighten Device test, the blood-based epigenetic biomarker test. Participants will then be interviewed at 2 weeks, 6 weeks, 3 months, and 6 months postpartum for the development of depression symptoms. They'll also complete a multitude of other outcome measures at each of these visits.

Inclusion Criteria:

• subject must be pregnant (singleton pregnancy)
• <30 weeks' gestation, age 18 or above
• able to provide written consent in English

Exclusion Criteria:

• The study team and/or PI may exclude anyone deemed unsafe to participate in the protocol.

Up to 500 pregnant women, aged 18 years or above

The investigators plan to share de-identified data with other researchers. Data shared will include demographic information, clinical data which will include SCID diagnosis, mental health surveys like EPDS, PASS, etc., sample analyses data.