Table 1.

Summary of data considered for meta-analysis and potential confounders.

Authors	Main stress outcome	Timing of the stressor	n	Tissue	Methylation assessment	Ethnicity	Observations
Oberlander et al. 200827	Maternal depression or anxiety during pregnancy, as assessed by HAM-D, HAM-A and EPDS	Psychiatric assessments at 2nd and 3rd trimesters	136	Cord blood	Pyrosequencing	Canadian recruited sample	This is the first study to explore NR3C1 methylation in humans in relation to early stress. Loss of significance due to unadjusted nature of the meta-analyzed results.
Radtke et al. 201133	Prenatal exposure to intimate partner violence, as assessed by CAS	During pregnancy (all trimesters)	23	Whole blood (at 14.1 ± 0.5 years)	Sodium bisulfite mapping, cloning and Sanger sequencing	Mixed origin of the sample including Turkey, Iraq and Kosovo, among others	This is the only study that studied pre-adolescent and adolescent subjects instead of newborns (or infants).
Mulligan et al. 201232	War stress, as assessed by trauma surveys	During pregnancy (all trimesters)	25	Cord blood	Sodium bisulfite mapping, cloning and Sanger sequencing	100% of the sample was recruited at the Democratic Republic of Congo	Although Mulligan et al. reported an overall significant effect of war stress upon NR3C1 methylation, they found no significant effect of individual CpG sites.
Hompes et al. 201329	Maternal depression or anxiety during pregnancy, as assessed by EPDS and PRAQ	Psychiatric assessments at 1st, 2nd and 3rd trimesters	74	Cord blood	MALDI-TOF mass spectrometry	93% of the sample was Belgian	Conflicting results may be due to the study of methylation in CpG units rather than in individual CpG sites.
Conradt et al. 201328	Maternal depression or anxiety during pregnancy, as assessed retrospectively from clinical records and interviews	Retrospective psychiatric assessment (all trimesters)	482	Placenta(fetal origin)	Pyrosequencing	73% of the sample was Caucasian	Since the included sample in Conradt et al. study is several folds higher than the others, their reported associations drive the meta-analysis results, even in a random effects model as can be seen by the accounted weight.
Braithwaite et al. 201530	Maternal depression during pregnancy, as assessed by EPDS	2nd or 3rd trimester of pregnancy	56	Buccal swabs (collected at 53.6 ± 9.99 days)	Pyrosequencing	89% of the sample was Caucasian	They successfully replicated Weaver and colleagues' findings in rats in male subjects but not in the females.As DNA methylation was examined in buccal swabs instead of cord or whole blood, replication of results suggests inter-reliability between tissues.
Murgatroyd et al. 201531	Maternal depression during pregnancy, as assessed by EPDS	2nd trimester of pregnancy (20 weeks)	181	Saliva (collected at 14 months)	MALDI-TOF mass spectrometry	96% of the sample identified themselves as white British	This is the only study to date to examine both prenatal and postnatal depression and their interaction on offspring methylation. They also described a moderating role of maternal stroking in final methylation values.As DNA methylation was examined in saliva instead of cord or whole blood, replication of results suggests inter-reliability between tissues.

Abbreviations: CAS, composite abuse scale; EPDS, Edinburgh Postnatal Depression Scale; HAM-A, Hamilton Rating Scale for Anxiety; HAM-D, Hamilton Rating Scale for Depression; PRAQ, pregnancy related anxiety questionnaire.