Table 3. Adjusted conditional odds ratios for the association between stress, socio-demographics, lifestyle, nutritional factors and gastroschisis (complete case).

Characteristic		Univariate Odds Ratio (95% CI)			Adjusted a Odds Ratio (95% CI)
Number of major stressful life events:- Serious relationship difficulties / Legal or financial problems / Victim of violence / Injury or illness / Death of someone close; first trimester	0	1.0			1.0
	1	1.3	(0.7,	2.4)	1.0	(0.4,	2.8)
	2+	2.8	(1.4,	5.5)	4.9	(1.2,	19.4)
Social support available:- Emotional, financial, Help with daily tasks; first trimester	No (lack of 1+ support)	1.0			1.0
	Yes (all 3 supports)	0.5	(0.3,	1.0)	0.8	(0.2,	3.1)
Same address for first 12 weeks of pregnancy	Yes	1.0			1.0
	No	3.3	(1.8,	5.8)	4.9	(1.7,	13.9)
Changed partner during this pregnancy from previous pregnancies	No	1.0			1.0
	Yes	2.7	(1.2,	6.0)	3.5	(0.8,	16.0)
	First pregnancy	0.9	(0.5,	1.6)	1.8	(0.6,	5.5)
NS-SEC classification (of mother)	Managerial and professional / intermediate	1.0			1.0
	Routine and manual occupations	3.2	(1.4,	7.3)	3.6	(0.9,	15.5)
	Unemployed	2.6	(1.1,	6.2)	1.2	(0.3,	5.1)
	Student	1.9	(0.5,	6.7)	1.0	(0.8,	6.0)
Cigarettes smoked per day in first trimester	0	1.0			1.0
	> 0 - 10	2.7	(1.5,	5.0)	3.9	(1.3,	11.4)
	> 10 cigarettes	3.5	(1.6,	7.6)	4.3	(1.0,	18.0)
Woman binge drinker (≥ 6 unitsb in one sitting/day) in first trimester	No	1.0			1.0
	Yes	2.0	(1.2,	3.4)	1.6	(0.6,	4.2)
Body Mass index	Underweight (<18.5)	1.8	(0.7,	4.7)	3.4	(0.6,	20.8)
	Normal (18.5-24.9)	1.0			1.0
	Overweight (25-29.9)	0.8	(0.4,	1.6)	0.8	(0.3,	2.5)
	Obese(30+)	0.3	(0.1,	0.8)	0.1	(0.03,	0.7)
Typical number of fruit or vegetables portions eaten per week (excluding potatoes) during the first trimester	≤ 6 portions a week	1.0			1.0
	7-13	0.7	(0.3,	1.6)	0.4	(0.1,	1.5)
	14-20	0.3	(0.2,	0.8)	0.2	(0.06,	0.9)
	21+	0.2	(0.1,	0.5)	0.2	(0.04,	0.8)
Duration in weeks of folic acid supplementation during first trimester	< 6 out of first 12 weeks	1.0			1.0
	≥ 6 out of first 12 weeks	0.3	(0.2,	0.6)	0.3	(0.1,	0.8)
Minimum caffeine intake per week in first trimester	0 - 1400mg	1.0			1.0
	> 1400 - 2800mg	1.4	(0.8,	2.6)	0.7	(0.3,	1.8)
	> 2800 - 4200mg	1.1	(0.4,	2.6)	0.3	(0.1,	1.5)
	>4200mg	3.3	(1.5,	7.4)	0.9	(0.2,	3.8)
Nausea or vomiting during the first trimester	No	1.0			1.0
	Yes	0.4	(0.2,	0.9)	0.4	(0.1,	1.5)

^aAdjusted for all variables in shown in the table using conditional logistic regression

^bA UK standard unit of alcohol is 10ml or 8g of pure alcohol. This is equivalent to half a pint of beer, one sixth of a gill of spirits, or a glass of wine (125ml). We have included this information in the methods section.