Table 3.

Associations of vegetarianism with maternal outcomes, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies–Singletons, 2009–2013

				Overall mean (SD) or proportiona		Self-defined vegetarianism			Diet-based vegetarianism
						Unadjusted OR (95% CI)	Adjusted OR (95% CI)		Unadjusted OR (95% CI)	Adjusted OR (95% CI)
Total GWG by IOM criteria
Inadequate GWG				33.79%	Vegetarian	0.97 (0.58, 1.62)	1.04 (0.61, 1.76)	Full vegetarian	1.23 (0.59, 2.59)	1.25 (0.57, 2.74)
								Pesco-vegetarian	0.82 (0.12, 5.76)	1.38 (0.18, 10.67)
								Semi-vegetarian	0.95 (0.68, 1.33)	0.88 (0.60, 1.28)
Excessive GWG				36.13%	Vegetarian	0.92 (0.55, 1.56)	1.00 (0.57, 1.72)	Full vegetarian	0.63 (0.26, 1.57)	0.78 (0.30, 2.01)
								Pesco-vegetarian	1.25 (0.21, 7.40)	1.33 (0.21, 8.54)
								Semi-vegetarian	1.10 (0.81, 1.49)	1.12 (0.80, 1.58)
Second-trimester GWG by IOM
Inadequate GWG				47.39%	Vegetarian	1.12 (0.68, 1.84)	1.28 (0.76, 2.16)	Full vegetarian	2.07 (0.92, 4.69)	2.24 (0.95, 5.27)
								Pesco-vegetarian	1.88 (0.20, 18.09)	2.88 (0.29, 28.54)
								Semi-vegetarian	1.17 (0.87, 1.57)	1.05 (0.76, 1.44)
Excessive GWG				25.26%	Vegetarian	1.12 (0.63, 2.01)	1.42 (0.77, 2.63)	Full vegetarian	1.19 (0.41, 3.55)	1.68 (0.53, 5.29)
								Pesco-vegetarian	3.56 (0.38, 33.31)	4.97 (0.49, 50.91)
								Semi-vegetarian	1.29 (0.91, 1.84)	1.24 (0.83, 1.85)
Third-trimester GWG by IOM
Inadequate GWG				26.68%	Vegetarian	0.98 (0.57, 1.68)	1.13 (0.64, 1.99)	Full vegetarian	1.69 (0.79, 3.61)	2.03 (0.89, 4.65)
								Pesco-vegetarian	—	—
								Semi-vegetarian	1.21 (0.87, 1.68)	1.08 (0.74, 1.57)
Excessive GWG				35.93%	Vegetarian	1.00 (0.61, 1.64)	1.19 (0.70, 2.03)	Full vegetarian	0.73 (0.30, 1.79)	1.01 (0.38, 2.66)
								Pesco-vegetarian	0.80 (0.18, 3.56)	0.81 (0.16, 4.16)
								Semi-vegetarian	1.22 (0.89, 1.67)	1.20 (0.84, 1.71)
Glycaemic status
Impaired glucose tolerance				4.16%	Vegetarian	0.85 (0.30, 2.41)	0.83 (0.27, 2.51)	Full vegetarian	1.32 (0.40, 4.43)	1.08 (0.28, 4.12)
								Pesco-vegetarian	—	—
								Semi-vegetarian	0.80 (0.43, 1.51)	0.97 (0.48, 1.93)
Gestational diabetes				4.36%	Vegetarian	1.25 (0.52, 3.05)	1.16 (0.43, 3.07)	Full vegetarian	0.83 (0.15, 4.71)	0.88 (0.15, 5.17)
								Pesco-vegetarian	—	—
								Semi-vegetarian	0.76 (0.40, 1.45)	0.93 (0.46, 1.89)
Hypertensive disorders
Mild gestational/ unspecified hypertension				2.98 %	Vegetarian	0.84 (0.26, 2.75)	1.25 (0.35, 4.38)	Full vegetarian	0.68 (0.09, 5.06)	1.48 (0.18, 12.21)
								Pesco-vegetarian	—	—
								Semi-vegetarian	1.43 (0.76, 2.69)	1.57 (0.77, 3.20)
Severe gestational				3.23%	Vegetarian	0.60 (0.14, 2.50)	0.65 (0.15, 2.91)	Full vegetarian	0.60 (0.08, 4.51)	0.83 (0.10, 6.90)
Hypertension/pre-eclampsia								Pesco-vegetarian	—	—
								Semi-vegetarian	0.48 (0.18, 1.25)	0.54 (0.20, 1.44)
						Unadjusted RR (95% CI)	Adjusted RR (95% CI)		Unadjusted RR (95% CI)	Adjusted RR (95% CI)
Gestational anaemia				24.38%	Vegetarian	0.79 (0.54, 1.16)	0.96 (0.66, 1.41)	Full vegetarian	0.64 (0.33, 1.23)	0.73 (0.38, 1.39)
								Pesco-vegetarian	1.09 (0.32, 3.66)	1.65 (0.49, 5.52)
								Semi-vegetarian	1.03 (0.82, 1.29)	1.01 (0.80, 1.28)

OR, odds ratio from logistic regression; RR, relative risk from log-binomial regression; SD, standard deviation; GWG, gestational weight gain; IOM, Institute of Medicine.

Adjusted models control for age, height, parity, pre-pregnancy BMI, race, marital status, education, income, current job/student status, insurance coverage, infant sex, total weekly physical activity, total energy and Healthy Eating Index-2010 (without total protein foods and seafood/plant-protein components). Non-estimable OR (95% CI)s presented as —.

Multiple imputation (20 iterations) used to address missing exposure, outcome and covariate data.

^aMean or proportion in 20 imputed data sets (n = 38 960).