Table 1. Maternal, Neonatal, and Family Characteristics Tested as Covariates by the 4-Class Exposure Status.

Characteristics	Exposure								Association of covariate with exposure status
	SSRI exposed		Psychiatric disorder, no medication		SSRI discontinued group		Unexposed		p-value
	n=15,729		n=9,651		n=7,980		n=31,394
	n	%	n	%	n	%	n	%
Maternal age									<.0001
≤19	524	3.3	954	9.9	217	2.7	775	2.5
20-29	7,426	47.2	4,530	46.9	3,632	45.5	15,523	49.5
30-39	7,023	44.7	3,768	39.0	3,826	47.9	13,959	44.5
≥40	756	4.8	399	4.1	305	3.8	1,137	3.6
Place of residence									<.0001
urban	10,687	68.0	6,706	69.5	5,608	70.3	21,233	67.8
semiurban	2,552	16.2	1,512	15.7	1,161	14.6	5,050	16.1
rural	2,489	15.8	1,427	14.8	1,209	15.2	5,054	16.1
Marital status at birth									<.0001
married or in relationship/divorced	13,364	89.6	7,918	88.1	6,940	92.4	28,832	95.5
Socioeconomic status									<.0001
upper white collar worker	1,857	11.8	1,219	12.6	1,207	15.1	5,360	17.1
lower white collar worker	4,954	31.5	2,824	29.3	2,683	33.6	10,479	33.4
blue collar worker	2,493	15.9	1,435	14.9	1,263	15.8	4,271	13.6
other a	3,669	23.3	2,365	24.5	1,499	18.8	5,728	18.3
unknown	2,756	17.5	1,808	18.7	1,328	16.6	5,556	17.7
Parity									<.0001
no previous births	6,534	41.6	4,455	46.2	3,665	45.9	12,817	40.8
Smoking during pregnancy	4,575	29.9	2,737	29.1	1,855	23.8	3,947	12.9	<.0001
Exposure to teratogenicb drugs	18	0.1	10	0.1	13	0.2	30	0.1	.44
Exposure to anxiolyticsc and sedatives	2,933	18.7	426	4.4	329	4.1	147	0.5	<.0001
Exposure to antiepilepticd drugs	500	3.2	162	1.7	77	1.0	136	0.4	<.0001
Entitlement to special reimbursement for any chronic disease ever	179	1.1	126	1.3	94	1.2	230	0.7	<.0001
Preterm birth <37wk	821	5.2	608	6.3	379	4.8	1,379	4.4	<.0001
Birth weight <2,500g	572	3.6	430	4.5	280	3.5	989	3.2	<.0001
Neonatal care unit	2,405	15.3	1,160	12.0	857	10.7	3,032	9.7	<.0001
Maternal history of other psychiatric diagnosese	3,589	22.8	2,532	26.2	997	12.5	612	2.0	<.0001
Maternal history of substance abusef	1,815	11.5	1.096	11.4	525	6.6	240	0.8	<.0001
Paternal history of psychiatric diagnosesg	3,393	21.6	2,251	23.3	1,356	17.0	2,885	9.2	<.0001
Mother's country of birth									<.0001
other than Finland	706	4.5	591	6.1	367	4.6	4,280	13.6
Parental death	422	2.7	243	2.5	162	2.0	261	0.8	<.0001

Note: Differences between the groups analyzed by χ² test and when not valid, by Fischer's exact test. Percentages were calculated from non-missing data. Missing values, n (%): place of residence, 66 (0.1); marital status, 3,158 (4.9); previous births, 20 (0.0); smoking during pregnancy, 1,629 (2.5); mother's country of birth, 1 (0.0). SSRI = selective serotonin reuptake inhibitor.

^aE.g. students, housewives, entrepreneurs, unemployed

^bTeratogenic drugs: purchases of isotretinoin (Anatomic-Therapeutic-Chemical [ATC], code D10BA), acitretin (D05BB02), antineoplastic agents (L01), methotrexate (L04AX03), mychophenolate (L04AA06), misoprostol (A02BB01 and M01AB55), carbimazole (H03BB01) any time during pregnancy or one month prior to pregnancy.

^cAnxiolytics and sedatives: purchases (ATC codes N05B, N05C) any time during pregnancy or one month prior to pregnancy.

^dAntiepileptic drugs: purchases (ATC code N03) any time during pregnancy or one month prior to pregnancy.

^eMaternal history of other psychiatric diagnoses: any other psychiatric diagnosis than depression-related disorders (F20-F48 used as inclusion/exclusion criteria) or substance abuse (International Classification of Diseases 10^th Revision [ICD-10] F50-F99; 9^th Revision [ICD-9] 299, 301-302, 307, 309, 312-319; 8^th Revision [ICD-8] 301, 302.10-302.99, 305-308, 310-315), recorded ever before delivery.

^fMaternal history of substance abuse: (ICD-10) F10-F19; (ICD-9) 291, 292, 303, 304, 305; (ICD-8) 291, 294.30, 303, 304, ever recorded.

^gPaternal history of psychiatric diagnoses: (ICD-10) F10-F99; (ICD-9) 291-292, 295-309, 312-319; (ICD-8) 291, 294.30, 295-301, 302.10-308, 310-315, ever recorded.