Thiopurines (Azathioprine, Mercaptopurin) updated on 07-28-2025

Small for gestational age (weight)

id	Study   Auto Vestergaard, 2024Reynolds, 2022Kanis, 2021Mahadevan, 2021Meyer b (Controls exposed to Anti-TNF), 2021Meyer b (Controls unexposed, sick), 2021Howren, 2020Lazzaroni, 2020Norgard, 2020Bröms (Crohn’s disease, stable disease), 2014Coelho (Controls exposed to 5-ASA), 2011Coelho (Controls unexposed, sick), 2011Cleary (Controls unexposed, NOS), 2009Cleary (Controls unexposed, sick), 2009	Lib. in paper	Exposition period  Auto during pregnancy (anytime or not specified)1st trimester2nd trimester3rd trimester2nd and/or 3rd trimesterthroughout pregnancyearly pregnancydays before deliverylate pregnancypreconception-onlypericonceptionalpreconceptional for kinetic reasonat least 1st trimester3 months (or more) before pregnancy or during pregnancy1st and 2nd trimester3 months or more before pregnancy or1st trimesterPaternal exp. genotoxic window only (0–3 months preconception)Paternal exposure: epigenetic window only (3–xxx months preconception)Paternal exposure: genotoxic/epigenetic window (0–xxx months preconception)Paternal exposure: other window	Study type  All studies Case control excluded Only case control	Control type    Auto unexposed (general population or NOS)unexposed, sickunexposed, disease freeexposed to other treatment, sicknot specifiedsiblingwhatever (meta-analysis)	Tags	OR 95%CI	x1/n1 x0/n0	no cases	no exposed	ROB	Ref.
S18482 R78419	Vestergaard, 2024	Small for Gestational Age (birth weight below the tenth percentile of newborns of the same gestational age)	during pregnancy (anytime or not specified)	retrospective cohort	unexposed, sick	Adjustment: No Indications: Inflammatory Bowel disease (IBD)	0.45 [0.17;1.19] C	5/111   35/372	40	111		ref
S13740 R53541	Reynolds, 2022	Intra uterine growth retardation (IUGR)	throughout pregnancy	retrospective cohort	unexposed, sick	Adjustment: No Indications: Systemic lupus erythematosus (SLE)	1.08 [0.49;2.42] C	10/82   21/185	31	82		ref
S12244 R46198	Kanis, 2021	Small for gestational age (weight below 2 SD for gestational age)	throughout pregnancy	retrospective cohort	unexposed, sick	Adjustment: No Indications: Inflammatory Bowel disease (IBD)	0.67 [0.27;1.63]	6/240   22/564	28	240		ref
S12218 R45544	Mahadevan, 2021	Small for Gestational Age (NOS)	3 months (or more) before pregnancy or during pregnancy excluded	prospective cohort	unexposed, sick	Adjustment: Yes Indications: Inflammatory Bowel disease (IBD)	0.50 [0.20;15.00] excluded (exposition period)	-/242   -/379	-	242		ref
S13576 R52618	Meyer b (Controls exposed to Anti-TNF), 2021	Small for gestational age (birth weights below the 10th percentile)	during pregnancy (anytime or not specified)	retrospective cohort (claims database)	exposed to other treatment, sick excluded	Adjustment: Yes Indications: Inflammatory Bowel disease (IBD)	0.69 [0.56;0.87] excluded (control group)	256/3,554   364/3,525	620	3,554		ref
S13454 R51828	Meyer b (Controls unexposed, sick), 2021	Small for gestational age (birth weights below the 10th percentile)	during pregnancy (anytime or not specified)	retrospective cohort (claims database)	unexposed, sick	Adjustment: Yes Indications: Inflammatory Bowel disease (IBD)	0.75 [0.64;0.89]	256/3,554   1,694/19,811	1,950	3,554		ref
S6724 R19606	Howren, 2020	Small for Gestational Age (less than the 10th percentile of gestational age and sex-specific weights for neonates in BC).	during pregnancy (anytime or not specified)	retrospective cohort (claims database)	unexposed, sick	Adjustment: Yes Indications: Rheumatic diseases (RD)	2.68 [0.81;8.85]	-/23   -/6,064	-	23		ref
S12240 R46211	Lazzaroni, 2020	Small for gestational age	during pregnancy (anytime or not specified)	retrospective cohort	unexposed, sick	Adjustment: No Indications: Systemic lupus erythematosus (SLE) Matched	0.15 [0.01;2.80] C	0/25   7/64	7	25		ref
S6294 R17066	Norgard, 2020	Small for gestational age (NOS)	3 months (or more) before pregnancy or during pregnancy excluded	population based cohort retrospective	unexposed (general population or NOS)	Adjustment: No Indications: Any or not specified	1.07 [0.78;1.46] C excluded (exposition period)	41/1,048   48,169/1,309,961	48,210	1,048		ref
S13765 R53599	Bröms (Crohn’s disease, stable disease), 2014	Small for gestational age (birth weights < 10th percentile)	during pregnancy (anytime or not specified)	population based cohort retrospective	unexposed, disease free	Adjustment: Yes Indications: Inflammatory Bowel disease (IBD)	0.51 [0.26;1.02]	9/-   46,637/467,057	46,646	-		ref
S12246 R45446	Coelho (Controls exposed to 5-ASA), 2011	Hypotrophy (birth weight under the 10th percentile of the standard French growth curves of Leroy and Lefort, based on birth weight and gestational term).	during pregnancy (anytime or not specified)	retrospective cohort	exposed to other treatment, sick excluded	Adjustment: No Indications: Inflammatory Bowel disease (IBD)	0.89 [0.19;4.24] C excluded (control group)	3/40   4/48	7	40		ref
S12195 R45441	Coelho (Controls unexposed, sick), 2011	Hypotrophy (birth weight under the 10th percentile of the standard French growth curves of Leroy and Lefort, based on birth weight and gestational term).	during pregnancy (anytime or not specified)	retrospective cohort	unexposed, sick	Adjustment: No Indications: Inflammatory Bowel disease (IBD)	2.11 [0.21;21.41] C	3/40   1/27	4	40		ref
S6258 R18036	Cleary (Controls unexposed, NOS), 2009	Small for Gestational age (weight) among singleton infants (2 standard deviations from expected weight as determined from sex and parity specific growth curves, constructed from the Medical Birth Register; Källén, 1995)	early pregnancy	population based cohort retrospective	unexposed (general population or NOS) excluded	Adjustment: Yes Indications: Any or not specified	2.34 [1.57;3.49] excluded (control group)	25/466   24,802/1,139,773	24,827	466		ref
S12174 R45198	Cleary (Controls unexposed, sick), 2009	Small for Gestational age (weight) among singleton infants (2 standard deviations from expected weight as determined from sex and parity specific growth curves, constructed from the Medical Birth Register; Källén, 1995)	early pregnancy	population based cohort retrospective	unexposed, sick	Adjustment: No Indications: Any or not specified	1.37 [0.88;2.14]	25/466   56/1,676	81	466		ref
					Total	9 studies	0.86 [0.61;1.20]		48,787	4,541
x1: number of endpoints among exposed, n1: number of exposed; x0: number of endpoints among non exposed, n0: number of non exposed; C: calculated odds ratio from numbers of events and effectives

Forest plot

Sensitivity analysis

Publication bias and p-hacking diagnosis

Sub-groups analysis using all included studies

excluded 6258, 12246, 13576

Umbrella review (other published meta-analyses)