Integrating multiple lines of evidence to assess the effects of maternal BMI on pregnancy and perinatal outcomes

Table 1 Characteristics of the included studies

Cohort	Source	Country	Year	Maximum N^a	BMI measurement	Maternal pre-pregnancy BMI [kg/m²]^b Mean (SD)	Maternal age at delivery [years] Mean (SD)
ALSPAC*	[23, 24]	UK	1991–1992	11,272	Self-reported pre-pregnancy	22.95 (3.82)	28.46 (4.78)
BiB*	[26]	UK	2007–2010	5018	Measure around 12 weeks of gestation	26.63 (5.99)	26.82 (5.96)
DNBC-GOYA*	[28, 29]	Denmark	1996–2002	2542	Self-reported pre-pregnancy	23.59 (4.30)	29.67 (4.20)
DNBC-PTB (controls)*	[32]	Denmark	1996–2002	1676	Self-reported pre-pregnancy	23.44 (3.98)	29.78 (4.10)
EFSOCH*	[34]	UK	2000–2004	789	Weight self-reported pre-pregnancy, height measured during pregnancy	24.02 (4.43)	30.64 (5.03)
FinnGen	[37]	Finland	1969–2018	190,879	NA	NA	NA
GEN-3G	[56]	Canada	2010–2013	582	Self-reported pre-pregnancy	25.04 (5.70)	28.27 (4.34)
GenR	[41]	Netherlands	2002–2006	4138	Measured before 20 weeks of gestation	25.31 (4.89)	28.50 (5.66)
HAPO*	[43]	USA	1999–2002	1310	Measured between 24 and 32 weeks of gestation	28.46 (4.82)	31.31 (5.27)
INMA	[46]	Spain	1997–2011	1035	Self-reported pre-pregnancy weight, height measured in the first trimester	23.37 (4.25)	30.72 (4.02)
MoBa*	[47, 57]	Norway	1999–2008	81,795	Self-reported at 15 weeks gestation	24.05 (4.32)	30.13 (4.72)
NFBC1966	[49]	Finland	1966	356	Self-reported pre-pregnancy	25.14 (4.78)	30.22 (5.9)
NFBC1986	[51]	Finland	1986	883	Self-reported pre-pregnancy	24.17 (4.61)	25.43 (2.64)^c
UK Biobank	[58]	UK	2006–2010	153,543	NA	NA	29.03 (6.34)^d

Abbreviations: ALSPAC Avon Longitudinal Study of Parents and Children, BiB Born in Bradford, DNBC-GOYA Danish National Birth Cohort-Genetics of Obesity in Young Adults Study, DNBC-PTB Danish National Birth Cohort-Preterm Birth Study, EFSOCH Exeter Family Study of Childhood Health, FinnGen FinnGen (release 8), GEN-3G Genetics of Glycaemic Regulation in Gestation and Growth, GenR Generation R, HAPO Hyperglycaemia and Adverse Pregnancy Outcome, INMA Infancia y Medio Ambiente (English translation = Childhood and the Environment), MoBa Norwegian Mother, Father and Child Cohort Study, NA Not available, NFBC1966 Northern Finland 1966 Birth Cohort, NFBC1986 Northern Finland 1986 Birth Cohort
^*Studies contributing to Mendelian randomisation analyses adjusted by offspring genotype
^aMaximum number of mothers with data on at least one outcome
^bMaternal BMI is only reported where collected pre- or early in pregnancy
^cThe relatively young age at delivery in the NFBC1986 cohort may be explained by the young age of the cohort at the time of the study
^dMaternal age in UK Biobank was taken from maternity record linkage on a subsample of participants and may therefore not be representative of the full sample included

ISSN: 1741-7015