First author Year of
publication 		Location Study
period 		Recruitment of cases Recruitment of controls Weight/height
measurement 		BMI
classification		 Adjusted for Outcomes
reported
Shaw et al.
[47] 		2000 California,
USA		 Jan 1987
to
Dec 1989 		Medical records of
California Counties
(live births and fetal deaths)		 Randomly selected from
California Counties
(live births) 		Retrospectively
self reported
by mother		 NWa ≤ 29
Obeseb > 29 		Stratified by
maternal race/
ethnic group		 CLP
CP
Oddy et al.
[55] 		2009 Western
Australia		 Sep 1997
to
Mar 2000 		Western Australian
Birth Defects Registry
(live births, stillbirths
and terminations)		 Random sample from
Western Australia
(life births) 		Retrospectively
self reported		 NWa 20 to < 25
OWc 25 to < 30
Obese 30+ 		Marital status,
maternal age,
maternal education,
folic acid intake		 Orofacial
cleftd

aExcluded because NW is not according to WHO classification.
bExcluded because obese is not according to WHO classification.
cExcluded because OW is not according to WHO classification.
dExcluded because orofacial cleft was not sub-divided.
NW = normal weight (reference weight); OW = overweight; CP = cleft palate; CLP = cleft lip with or without palate; orofacial cleft = CP+CLP; BMI = body mass index.