Table 1.

Findings of reviewed structural, functional and molecular imaging studies in peripartum women and in unipolar postpartum depression

Author (year) [reference]	Method	Sample	Paradigm	Findings
STRUCTURAL
Kim et al. (2010) [39]	VBM	N=19 (19 postpartum women with minimal to moderate depression at 2–4 weeks and 3–4 months)	Prospective longitudinal study (during postpartum period)	In postpartum women across postpartum period: ↑GM volume in superior, middle, and inferior PFC, precentral and postcentral gyrus ↑GM volume in superior and inferior parietal lobe, insula, and thalamus
Hoekzema et al. (2017) [41]	fMRI	N=81 (25 primiparous women pre-pregnancy, early postpartum and at 2 years postpartum 20 nulliparous women at time period comparable to primiparous women 19 first time fathers prior to and following partner’s pregnancy 17 control men without children)	Prospective longitudinal study (before pregnancy v. postpartum)	In postpartum scans v. prepartum scans: ↓GM volume in anterior and posterior midline (from the MFC to ACC) ↓GM volume in bilateral lateral PFC and bilateral temporal cortex ↓Surface area and cortical thickness In postpartum women at 2 years postpartum: ↑GM volume in left HIPP from early postpartum scan *All other GM volume reductions above persisted In first time fathers v. control men without children: *No changes in GM volumes across time period
FUNCTIONAL
Bannbers et al. (2013) [53]	BOLD activation	N=26 (13 healthy postpartum women at 48 hours and 4–7 weeks postpartum 13 healthy non-pregnant women during luteal and follicular phase)	Go/NoGo response inhibition task	In postpartum women v. non-pregnant women: ↓bilateral inferior frontal gyri, right precentral gyrus activity In early postpartum women v. late postpartum women: ↑right inferior frontal gyrus, right ACC, bilateral precentral gyri
Gingnell et al. (2015) [54]	BOLD activation	N=28 (13 healthy postpartum women at 48 hours and 4–6 weeks postpartum 15 healthy non-pregnant women during luteal and follicular phase)	Adult emotional face matching task	In postpartum women v. non-pregnant women: ↑insula, inferior frontal gyrus activity In early postpartum women v. late postpartum women: ↓right insula, left middle frontal gyrus, bilateral inferior frontal gyrus activity In early postpartum period: Insula and inferior frontal gyrus activity ~ state anxiety In late postpartum period: Insula and inferior frontal gyrus activity ~ depression
Silverman et al. (2007) [55]	BOLD activation (pilot study)	N=8 (4 PPD women 7–8 weeks postpartum 8 healthy women 7–8 weeks postpartum)	Word/non-word task for emotionally valanced words (positive, negative threat/non-threat, neutral)	In PPD v. healthy women: ↓right AMYG, bilateral posterior orbitofrontal cortex activity with negative stimuli ↑bilateral insula activity with negative stimuli ↓striatal activation with positive stimuli
Silverman et al. (2011) [56]	BOLD activation	N=17 (6 PPD women 6–8 weeks postpartum 11 healthy women 6–8 weeks postpartum)	Word/non-word task for emotionally valanced words (positive, negative threat/non-threat, neutral)	In PPD v. healthy women: ↓right AMYG activation with negative stimuli
Moses-Kolko et al. (2010) [61]	BOLD activation	N=30 (14 PPD women 4–13 weeks postpartum 16 healthy women 4–13 weeks postpartum)	Adult emotional face matching task	In PPD v. healthy women: ↓left AMYG activity ↓right AMYG activity ~ ↑ infant-related hostility ↓left dorsomedial PFC activity with negative emotional faces ↓functional connectivity between left dorsomedial PFC and left AMYG
Moses-Kolko et al. (2011) [62]	BOLD activation	N=24 (12 PPD women <10 weeks postpartum 12 healthy women <10 weeks postpartum)	Card guessing task with monetary reward	In PPD v. healthy women: No difference in initial left ventral striatum activity with reward ↑attenuation of ventral striatal activity after reward
Barrett et al. (2012) [51]	BOLD activation	N=22 (22 healthy women at initial recruitment, 2 months and 3 months postpartum)	Emotional face affect rating task (positive and negative images of own and other infant)	In depressed, anxious subjects: ↓AMYG, thalamus, temporal cortex activity with own positive v. unfamiliar positive faces
Wonch et al. (2016) [65]	BOLD activation	N=45 (28 PPD women 2–5 months postpartum 17 healthy women 2–5 months postpartum)	Positive emotional affect rating task (positive own infant face, other infant face, non-infant images)	In PPD v. healthy women: ↑right AMYG activity in all tasks ↓AMYG-right insular cortex connectivity with own-other infant faces
Deligiannidis et al. (2013) [27]	BOLD resting state	N=17 (8 PPD women < 9 weeks of delivery 9 healthy women < 9 weeks of delivery)	Resting state	In PPD vs. healthy women: ↓connectivity between the ACC and left DLPFC and bilateral AMYG ↓connectivity between bilateral AMYG, ACC, and bilateral DLPFC ↓connectivity left DLPFC and right AMYG ↓connectivity between the right HIPP and right DLPFC
Chase et al. (2014) [76]	BOLD resting state	N=37 (14 PPD women <12 weeks postpartum 23 healthy women <12 weeks postpartum)	Resting state	In PPD v. healthy women: ↓posterior cingulate cortex-right AMYG connectivity
MOLECULAR
Sacher et al. (2010) [85]	PET	N=30 (15 healthy women 4–6 days postpartum 15 healthy non-postpartum women)	PET scan w/carbon-11 harmine	In healthy postpartum women v. healthy non-postpartum women: ↑MAO-A total volume distribution in the PFC, ACC, anterior temporal cortex, thalamus, dorsal putamen, HIPP, and midbrain by 43%
Sacher et al. (2015) [86]	PET	N= 57 (15 PPD women <18 months postpartum 12 healthy postpartum women who cry due to sad mood <18 months postpartum 15 asymptomatic healthy postpartum women <18 months postpartum 15 healthy non-postpartum women)	PET scan w/carbon-11 harmine	In PPD women v. healthy postpartum women: ↑MAO-A density by 22% in PFC ↑MAO-A density by 19% in ACC In healthy postpartum women who cry due to sad mood vs. healthy postpartum women: ↑MAO-A density by 15% in PFC ↑MAO-A density by 13% ACC
Moses-Kolko et al. (2012) [88]	PET	N=63 (13 postpartum unipolar depressed women early postpartum 7 postpartum bipolar depressed women early postpartum 13 healthy postpartum women early postpartum 10 non-postpartum unipolar depressed women early follicular phase 7 non-postpartum bipolar depressed women early follicular phase 13 non-postpartum healthy early follicular phase)	PET scan w/carbon-11 raclopride	In unipolar depression and all postpartum patients v. healthy non-postpartum and non-postpartum bipolar depressed: ↓D2/3 receptor binding in whole striatum In postpartum depressed v. healthy postpartum women: *No difference in D2/3 receptor binding
Moses-Kolko et al. (2008) [92]	PET	N=16 (9 PPD women 4 to 13 weeks postpartum 7 healthy postpartum 4 to 13 weeks postpartum)	PET scan w/carbon-11 WAY100635	In PPD women v. healthy postpartum: ↓Serotonin receptor binding in the mesiotemporal cortex, subgenual ACC, and left lateral orbitofrontal cortex by magnitude of 17–27%
Epperson et al. (2006) [100]	MRS	N=33 (9 PPD women <6 months postpartum prior to re-starting of menstruation 14 postpartum healthy women <6 months postpartum prior to re-starting of menstruation 10 healthy women during follicular phase of menstruation)	MRS to measure occipital cortex GABA concentration	In PPD women and healthy postpartum women v. healthy follicular phase women: ↓GABA concentrations in the occipital cortex In PPD women v. healthy postpartum women: *No differences in GABA concentrations in the occipital cortex
McEwen et al. (2012) [103]	MRS	N=24 (12 PPD women 3 weeks to 3 months postpartum 12 healthy postpartum women 3 weeks to 3 months postpartum)	MRS to measure MPFC glutamate concentration	In PPD women v. healthy postpartum women: ↑Glutamate concentration in the MPFC

Abbreviations: ACC- anterior cingulate cortex, AMYG- amygdala, BOLD- blood-oxygen-level-dependent, DLPFC- dorsolateral prefrontal cortex, fMRI- functional magnetic resonance imaging, GABA- γ-aminobutyric acid A, GM- grey matter, HIPP- hippocampus, MAO-A- monoamine oxidase-A, MFC- medial frontal cortex, MPFC- medial prefrontal cortex, MRS- magnetic resonance spectroscopy, PET- positron emission tomography, PFC- prefrontal cortex, PPD- postpartum depressed, VBM- voxel based morphometry.