Table 1

Effect of dietary and lifestyle interventions in pregnancy on primary outcomes (weight gain in pregnancy and birth weight) and secondary weight related outcomes ranked as critically important by Delphi survey (except for exceeding IOM recommendations)

No of studiesNo of participantsSummary estimate (95% CI)P valueI2 (%)
Dietary intervention
Weight gain in pregnancy (kg)1025-28 31-362560−3.84* (−5.22 to −2.45)<0.00192
Birth weight (g) 1026-28 30-362861−60* (−190 to 80)0.4184
Small for gestational age328 30 3122521.02† (0.75 to 1.37)0.910
Large for gestational age528 29 31 34 3523780.78† (0.51 to 1.19)0.2663
Exceeds IOM recommendations0
Physical activity
Weight gain in pregnancy (kg)1437-39 42 43 45-48 50-541057−0.72* (−1.20 to −0.25)0.00330
Birth weight (g)1437-40 42 44-50 52 531369−60* (−120 to −10)0.020
Small for gestational age437 38 46 534091.28† (0.52 to 3.15)0.600
Large for gestational age438 39 46 523550.52† (0.25 to 1.09)0.080
Exceeds IOM recommendations146740.33† (0.11 to 0.98)0.05NA
Mixed approach
Weight gain in pregnancy (kg)107 56 59-63 65-671864−1.06* (−1.67 to −0.46)<0.00136
Birth weight (g)757 59 61-63 65 66104810* (−50 to 70)0.860
Small for gestational age458 63 65 668910.88† (0.53 to 1.44)0.600
Large for gestational age957-59 61 62 63 65-6715001.05† (0.79 to 1.40)0.720
Exceeds IOM recommendations461 63 65 668990.89† (0.71 to 1.13)0.3356
All interventions
Weight gain in pregnancy (kg)345481−1.42* (−1.89 to −0.95)<0.00180
Birth weight (g)315278−50* (−100 to 0)0.0857
Small for gestational age1135521.00† (0.78 to 1.28)0.990
Large for gestational age1842330.85† (0.66 to 1.09)0.2138
Exceeds IOM recommendations58730.85† (0.66 to 1.11)0.2160

IOM=Institute of Medicine; NA=not applicable.

*Mean difference.

†Relative risk.