Table 2.

Population based studies included in the review

Author	Publication Date	Study Location	Cohort Size	Study Design	Diagnostic Criteria	Relevant Exposure	Findings
Connolly et al. [31]	Aug-16	Cincinnati Children’s Hospital Medical Center’s 2009–2014	503	case control	ICD9	pre pregnancy weight/BMI, GDM	Maternal obesity (BMI≥ 30) and GDM were associated with approximately 1.5-fold increased odds of having a child with an ASD. For mothers with both GDM and obesity, the association was twofold.
Cordero et al. [80]	Jun-19	The Study to Explore Early Development (SEED) is a U.S. multisite. California, Colorado, Georgia, Maryland, North Carolina, and Pennsylvania	698	case control	ADOS and ADI-R	pre pregnancy DM, GDM and HTN prior and during pregnancy	Hypertension (pre pregnancy and PIH/preeclampsia) was associated with ASD (aOR = 1.69 [95% CI 1.26, 2.26]). Diabetes (pre gestational an GDM clustered) during pregnancy was not associated with ASD (aOR = 1.10 [95% CI 0.77, 1.56]).
Dodds et al. [81]	Jul-11	1990 and 2002 in Nova Scotia	924	cohort	ICD-9 or ICD-10	pregnancy wt gain, pre pregnancy weight, pre pregnancy HTN, HTN during pregnancy	Univariate: Pregnancy weight gain ≥18 kg RR 1.26 (1.08–1.47), Pregnancy induced hypertension (PIH) RR 1.24 (1.02–1.52), pre pregnancy weight >90kg RR 1.72 (1.39–2.13), pre gestational DM RR1.98 (0.94–4.16), materal weight at delivery >120kg RR 2.18 (1.1–3.16), GDM RR 1.29 (0.9–1.83). Multivariate: Pre-pregnancy weight ≥90 kg RR 1.58 (1.26–1.98), Pregnancy weight gain ≥18 kg RR 1.19 (1.02–1.39), no other data.
Getz et al. [82]	Sep-16	General Practice Research Database from 1993 through 2008 (“about 6% of the population of England, Nortern Ireland, Scotland and Wales”	889	case control	E140.00 Infantile autism, *diagnostic source was not reported	maternal pre-pregnancy BMI	ORs for maternal obesity 1.54 [95% CI: 1.26, 1.89]
Krakowiak et al. [83]	May-12	CHARGE (Childhood Autism Risks from Genetics and the Environment) study in California, January 2003 and June 2010	517	case control	ADOS and ADI-R	maternal T2D or GDM in the index pregnancy. Other conditions of interest were hypertension and obesity, defined as BMI >30 with onset before index pregnancy	The association between diabetes (T2DM or GDM) and ASD did not reach statistical significance, the association between hypertension (during pregnancy and before) and ASD was not signinficant. The risk of having a child with ASD to TD, was significantly increased among obese women (ASD, OR: 1.67 [95% CI: 1.10–2.56],
Mann et al. [85]	May-10	South Carolina, 1996 through 2002	472	case control	ICD-9	Pre-eclampsia/eclampsia	OR 1.69 (1.26–2.28)
Shen et al. [86]	Jan-18	Han Chinese population.	705	case control	DSM-IV-TR	maternal pre-pregnancy BMI, GWG	Excessive GWG was associated with autism risk (OR = 1.327, 95% CI: 1.021–1.725) Excessive GWG increased the risk of autism in overweight/obese mothers (OR = 2.468, 95% CI: 1.102–5.526)
Surén et al. [87]	May-14	Norwegian Mother and Child Cohort Study	419	case control	DSM-IV-TR	Maternal and paternal height and weight were recorded in a questionnaire completed by the mothers during week 18 of pregnancy	Maternal BMI <18.5: OR 1.39 (0.79–2.46) BMI 25.0–29.9 : 1.29 (0.99–1.69) BMI >30.0: 1.17 (0.81–1.7)
Walker et al. [88]	Feb-15	California January 29, 2003, through April 7, 2011, (CHARGE) study	517	case control	ADOS and ADI-R	Preeclampsia	OR 2.36; 95% CI, 1.18–4.68);”
Windham et al. [89]	Feb-19	Study to Explore Early Development (SEED), a multi-site case-control study of children born in 2003–2006. California, Colorado, Georgia, Maryland, North Carolina, and Pennsylvania	540	case control	ADOS and ADI-R	Maternal height, weight, and GWG were self-reported	BMI ≥25 & < 30 1.25 (0.94–1.68), BMI>30 OR 1.37 (0.98–1.92). GWG 35–44lb OR 1.52 (1.05–2.22) GWG >44lb OR = 1.58 (1.08–2.31)
Xiang et al. [90]	Jun-19	Kaiser Permanente Southern California (KPSC) hospitals between January 1, 2012, and December 31, 2013	707	cohort	ICD-9	HbA1c screening in the early prenatal period	HbA1c > 6.5% (n-15) HR 1.79 (1.06–3.00)