Frequency, trends, and antecedents of severe maternal depression after three million U.S. births

Abstract

Background: Postpartum depression carries adverse consequences for mothers and children, so widespread screening during primary care visits is recommended. However, the rates, timing, and factors associated with significant depressive episodes are incompletely understood.

Methods and findings: We examined the Healthcare Cost and Utilization Project (HCUP) State Inpatient, Emergency Department, and Ambulatory Surgery and Services Databases from California (2005-2011) and Florida (2005-2012). Within 203 million records, we identified 3,213,111 births and all mothers who had hospital encounters for severe depression within 40 weeks following delivery. We identified 15,806 episodes of postpartum depression after 11,103 deliveries among 10,883 unique women, and calculated an overall rate of 36.7 depression- associated hospital visits per 10,000 deliveries. Upward trends were observed in both states, with combined five-year increases of 34%. First depressive events were most common within 30 days of delivery, but continued for the entire observation period. About half (1,661/3,325) of PPD first episodes occurred within 34 days of delivery, 70% (2,329/3,325) by the end of the second month, and 87% (2,893/3,325) before four-months of the delivery. Women with private insurance were less likely to have hospital encounters for depression than women with public insurance and women with depression were much more likely to have had some kind of hospital encounter at some time during their pregnancies. Rates of depression increased with the number of prenatal hospital encounters in a "dose-dependent" fashion: the rate of depression was 17.2/10,000 for women with no prenatal hospital visits, doubling for women with at least one encounter (34.9/10,000), and increasing 7-fold to 126/10,000 for women with three or more encounters during their pregnancies.

Conclusions: Our findings suggest that (1) hospital encounters for post-partum depression are increasing, (2) screening should begin very early and continue for the first year after delivery, and (3) added attention should be given to women who had hospital encounters during their pregnancies.

Fig 1. Temporal trends for all depression and PPD diagnoses per 10,000 deliveries for California (p < 0.01 for both trends) and Florida (p < 0.02 for both trends).

Fig 2

(Top panel) Timing of onset of the first ED visit or inpatient admission for a specific diagnosis of postpartum depression (PPD). Each vertical bar aggregates a week of hospital encounters. (Bottom panel) Similar histogram, but for the first hospital encounters for all severe depression.

Fig 3

(Top panel) Histogram of hospital encounters among women who were assigned specific postpartum depression ICD9-CM codes. To the left of zero are visits for all causes prior to delivery and to the right of zero are visits at which the diagnosis of PPD was first assigned. Patients diagnosed with depression in the 9 months after the delivery (light blue bars) are admitted and/or visit the ED department for a diverse set of conditions during pregnancy (dark blue bars), including mental health conditions (dark orange bars). The majority of specific PPD diagnoses are assigned in the first months after delivery, with a long tail of small numbers thereafter. (Bottom panel): A similar histogram for all women with depression (see text). Although a specific PPD diagnosis is less common, first visits for depression continue steadily.

Fig 4

(Top panel) Rates of postpartum depression among women with differing insurance status as influenced by the number of prenatal hospital encounters. (Bottom panel) Rates of postpartum depression among women of differing insurance status as influenced by number of prenatal hospital encounters for mental health conditions. Note scale change: top rates are per 10,000 deliveries, bottom rates are per 100 deliveries.