Table 2

Effect of dietary and lifestyle interventions in pregnancy on secondary maternal outcomes (ranked as critically important by Delphi survey, except for vaginal delivery and gestational age at birth). Summary estimates are relative risks unless stated otherwise

No of studiesNo of participantsSummary estimate (95% CI)P valueI2 (%)
Dietary intervention
Gestational diabetes mellitus333 35 364090.39 (0.23 to 0.69)0.00121
Pre-eclampsia628 30 31 34-3626240.67 (0.53 to 0.85)<0.0010
Gestational hypertension235 362820.30 (0.10 to 0.88)0.030
Preterm delivery426 30 31 3514740.68 (0.48 to 0.96)0.0335
Caesarean section528 29 31 35 3622730.93 (0.84 to1.04)0.1949
Vaginal delivery231 344720.97 0.89 to 1.07)0.560
Induction of labour428 31 34 3522771.12 (0.99 to 1.27)0.0760
Postpartum haemorrhage228 3512320.90 (0.57 to 1.42)0.640
Gestational age at delivery (weeks)628 30-32 34 352625−0.05* (−0.18 to 0.08)0.4271
Physical activity
Gestational diabetes mellitus0
Pre-eclampsia0
Gestational hypertension0
Preterm delivery537 38 46 52 534501.22 (0.51 to 2.90)0.650
Caesarean section537 39 48-505420.88 (0.66 to 1.17)0.380
Vaginal delivery337 39 494881.02 (0.93 to 1.11)0.700
Induction of labour0
Postpartum haemorrhage0
Gestational age at delivery (weeks)1137-39 42 44-49 5412500.03* (−0.14 to 0.20)0.740
Mixed approach
Gestational diabetes mellitus661 62 63 65-6712331.18 (0.78 to 1.77)0.440
Pre-eclampsia459 63 65 667181.16 (0.70 to 1.90)0.5739
Gestational hypertension459 63 65 667791.08 (0.75 to 1.55)0.6942
Preterm delivery457 63 65 667280.90 (0.55 to 1.47)0.687
Caesarean section856 57 59 61 63 65-6714070.94 (0.79 to 1.13)0.5310
Vaginal delivery157341.25 (0.88 to 1.78)0.21NA
Induction of labour159851.17 (0.78 to 1.75)0.44NA
Postpartum haemorrhage0
Gestational age at delivery (weeks)657 59 61 62 65 668130.20* (−0.02 to 0.42)0.071
All interventions
Gestational diabetes mellitus916420.78 (0.57 to 1.08)0.1329
Pre-eclampsia1033420.74 (0.60 to 0.92)0.00631
Gestational hypertension610610.89 (0.64 to 1.25)0.5150
Preterm delivery1326520.78 (0.60 to 1.02)0.070
Caesarean section1842220.93 (0.85 to 1.01)0.103
Vaginal delivery69941.00 (0.94 to 1.07)0.910
Induction of labour523621.12 (1.00 to 1.26)0.0547
Postpartum haemorrhage212320.90 (0.57 to 1.42)0.640
Gestational age at delivery (weeks)2346880.02* (−0.08 to 0.11)0.7233

NA=not applicable.

*Mean difference.