Scolaris Content Display Scolaris Content Display

Comparison 1 Any antioxidants versus control or placebo, Outcome 1 Pre‐eclampsia (subgroups by whether random or quasi‐random allocation).
Figures and Tables -
Analysis 1.1

Comparison 1 Any antioxidants versus control or placebo, Outcome 1 Pre‐eclampsia (subgroups by whether random or quasi‐random allocation).

Comparison 1 Any antioxidants versus control or placebo, Outcome 2 Preterm birth (< 37 weeks).
Figures and Tables -
Analysis 1.2

Comparison 1 Any antioxidants versus control or placebo, Outcome 2 Preterm birth (< 37 weeks).

Comparison 1 Any antioxidants versus control or placebo, Outcome 3 Small‐for‐gestational age.
Figures and Tables -
Analysis 1.3

Comparison 1 Any antioxidants versus control or placebo, Outcome 3 Small‐for‐gestational age.

Comparison 1 Any antioxidants versus control or placebo, Outcome 4 Stillbirth.
Figures and Tables -
Analysis 1.4

Comparison 1 Any antioxidants versus control or placebo, Outcome 4 Stillbirth.

Comparison 1 Any antioxidants versus control or placebo, Outcome 5 Neonatal death.
Figures and Tables -
Analysis 1.5

Comparison 1 Any antioxidants versus control or placebo, Outcome 5 Neonatal death.

Comparison 1 Any antioxidants versus control or placebo, Outcome 6 Elective delivery (induction of labour or elective caesarean section).
Figures and Tables -
Analysis 1.6

Comparison 1 Any antioxidants versus control or placebo, Outcome 6 Elective delivery (induction of labour or elective caesarean section).

Comparison 1 Any antioxidants versus control or placebo, Outcome 7 Bleeding episodes (including placental abruption, APH, PPH, need for transfusion).
Figures and Tables -
Analysis 1.7

Comparison 1 Any antioxidants versus control or placebo, Outcome 7 Bleeding episodes (including placental abruption, APH, PPH, need for transfusion).

Comparison 1 Any antioxidants versus control or placebo, Outcome 8 Serious maternal morbidity (including eclampsia, liver and renal failure, DIC, stroke).
Figures and Tables -
Analysis 1.8

Comparison 1 Any antioxidants versus control or placebo, Outcome 8 Serious maternal morbidity (including eclampsia, liver and renal failure, DIC, stroke).

Comparison 1 Any antioxidants versus control or placebo, Outcome 9 Gestational age at birth.
Figures and Tables -
Analysis 1.9

Comparison 1 Any antioxidants versus control or placebo, Outcome 9 Gestational age at birth.

Comparison 1 Any antioxidants versus control or placebo, Outcome 10 Birthweight.
Figures and Tables -
Analysis 1.10

Comparison 1 Any antioxidants versus control or placebo, Outcome 10 Birthweight.

Comparison 1 Any antioxidants versus control or placebo, Outcome 11 Length of stay in hospital‐neonatal.
Figures and Tables -
Analysis 1.11

Comparison 1 Any antioxidants versus control or placebo, Outcome 11 Length of stay in hospital‐neonatal.

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 1 Pre‐eclampsia.
Figures and Tables -
Analysis 2.1

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 1 Pre‐eclampsia.

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 2 Preterm birth (< 37 weeks).
Figures and Tables -
Analysis 2.2

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 2 Preterm birth (< 37 weeks).

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 3 Small‐for‐gestational age.
Figures and Tables -
Analysis 2.3

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 3 Small‐for‐gestational age.

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 4 Stillbirth.
Figures and Tables -
Analysis 2.4

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 4 Stillbirth.

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 5 Neonatal death.
Figures and Tables -
Analysis 2.5

Comparison 2 Any antioxidants versus control or placebo (sensitivity analyses based on trial quality), Outcome 5 Neonatal death.

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 1 Pre‐eclampsia.
Figures and Tables -
Analysis 3.1

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 1 Pre‐eclampsia.

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 2 Preterm birth.
Figures and Tables -
Analysis 3.2

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 2 Preterm birth.

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 3 Small‐for‐gestational‐age infant.
Figures and Tables -
Analysis 3.3

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 3 Small‐for‐gestational‐age infant.

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 4 Stillbirth.
Figures and Tables -
Analysis 3.4

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 4 Stillbirth.

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 5 Neonatal death.
Figures and Tables -
Analysis 3.5

Comparison 3 Any antioxidants versus control or placebo (subgroups by risk status), Outcome 5 Neonatal death.

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 1 Pre‐eclampsia.
Figures and Tables -
Analysis 4.1

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 1 Pre‐eclampsia.

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 2 Preterm birth.
Figures and Tables -
Analysis 4.2

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 2 Preterm birth.

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 3 Small‐for‐gestational age.
Figures and Tables -
Analysis 4.3

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 3 Small‐for‐gestational age.

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 4 Stillbirth.
Figures and Tables -
Analysis 4.4

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 4 Stillbirth.

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 5 Neonatal death.
Figures and Tables -
Analysis 4.5

Comparison 4 Any antioxidants versus control or placebo (subgroups by gestation at entry), Outcome 5 Neonatal death.

Comparison 5 Any antioxidants versus control or placebo (subgroups according to dose), Outcome 1 Pre‐eclampsia.
Figures and Tables -
Analysis 5.1

Comparison 5 Any antioxidants versus control or placebo (subgroups according to dose), Outcome 1 Pre‐eclampsia.

Comparison 5 Any antioxidants versus control or placebo (subgroups according to dose), Outcome 2 Stillbirth.
Figures and Tables -
Analysis 5.2

Comparison 5 Any antioxidants versus control or placebo (subgroups according to dose), Outcome 2 Stillbirth.

Comparison 5 Any antioxidants versus control or placebo (subgroups according to dose), Outcome 3 Neonatal death.
Figures and Tables -
Analysis 5.3

Comparison 5 Any antioxidants versus control or placebo (subgroups according to dose), Outcome 3 Neonatal death.

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 1 Pre‐eclampsia.
Figures and Tables -
Analysis 6.1

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 1 Pre‐eclampsia.

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 2 Preterm birth (< 37 weeks).
Figures and Tables -
Analysis 6.2

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 2 Preterm birth (< 37 weeks).

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 3 Small‐for‐gestational age.
Figures and Tables -
Analysis 6.3

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 3 Small‐for‐gestational age.

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 4 Stillbirth.
Figures and Tables -
Analysis 6.4

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 4 Stillbirth.

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 5 Neonatal death.
Figures and Tables -
Analysis 6.5

Comparison 6 Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents), Outcome 5 Neonatal death.

Comparison 7 Any antioxidants versus control or placebo (subgroups according to dietary intake at entry), Outcome 1 Pre‐eclampsia.
Figures and Tables -
Analysis 7.1

Comparison 7 Any antioxidants versus control or placebo (subgroups according to dietary intake at entry), Outcome 1 Pre‐eclampsia.

Comparison 7 Any antioxidants versus control or placebo (subgroups according to dietary intake at entry), Outcome 2 Stillbirth.
Figures and Tables -
Analysis 7.2

Comparison 7 Any antioxidants versus control or placebo (subgroups according to dietary intake at entry), Outcome 2 Stillbirth.

Comparison 7 Any antioxidants versus control or placebo (subgroups according to dietary intake at entry), Outcome 3 Neonatal death.
Figures and Tables -
Analysis 7.3

Comparison 7 Any antioxidants versus control or placebo (subgroups according to dietary intake at entry), Outcome 3 Neonatal death.

Table 1. Any antioxidants ‐ hypertension (undefined)

Antioxidants n/N

Control n/N

RR

95% CI

11/100

7/100

1.57

0.63 to 3.89

Figures and Tables -
Table 1. Any antioxidants ‐ hypertension (undefined)
Comparison 1. Any antioxidants versus control or placebo

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia (subgroups by whether random or quasi‐random allocation) Show forest plot

7

6082

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.50, 0.75]

1.1 Studies with random allocation

6

1061

Risk Ratio (M‐H, Fixed, 95% CI)

0.45 [0.31, 0.66]

1.2 Studies with quasi‐random allocation

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.70 [0.55, 0.90]

2 Preterm birth (< 37 weeks) Show forest plot

3

583

Risk Ratio (M‐H, Fixed, 95% CI)

1.38 [1.04, 1.82]

2.1 Studies with random allocation

3

583

Risk Ratio (M‐H, Fixed, 95% CI)

1.38 [1.04, 1.82]

2.2 Studies with quasi‐random allocation

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

3 Small‐for‐gestational age Show forest plot

3

634

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.47, 0.87]

3.1 Studies with random allocation

3

634

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.47, 0.87]

3.2 Studies with quasi‐random studies

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

4 Stillbirth Show forest plot

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

4.1 Studies with random allocation

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.00 [0.18, 5.76]

4.2 Quasi‐random studies only

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.58, 1.17]

5 Neonatal death Show forest plot

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

5.1 Studies with random allocation

1

181

Risk Ratio (M‐H, Fixed, 95% CI)

0.69 [0.12, 4.03]

5.2 Studies with quasi‐random allocation (death before 8 days)

1

4895

Risk Ratio (M‐H, Fixed, 95% CI)

1.41 [0.84, 2.37]

6 Elective delivery (induction of labour or elective caesarean section) Show forest plot

1

200

Risk Ratio (M‐H, Fixed, 95% CI)

2.0 [0.51, 7.78]

6.1 Induction of labour

1

200

Risk Ratio (M‐H, Fixed, 95% CI)

2.0 [0.51, 7.78]

7 Bleeding episodes (including placental abruption, APH, PPH, need for transfusion) Show forest plot

2

483

Risk Ratio (M‐H, Random, 95% CI)

1.58 [0.08, 31.47]

7.1 Studies with random allocation

2

483

Risk Ratio (M‐H, Random, 95% CI)

1.58 [0.08, 31.47]

7.2 Studies with quasi‐random allocation

0

0

Risk Ratio (M‐H, Random, 95% CI)

0.0 [0.0, 0.0]

8 Serious maternal morbidity (including eclampsia, liver and renal failure, DIC, stroke) Show forest plot

1

251

Risk Ratio (M‐H, Fixed, 95% CI)

0.39 [0.02, 9.42]

8.1 Eclampsia (studies with random allocation)

1

251

Risk Ratio (M‐H, Fixed, 95% CI)

0.39 [0.02, 9.42]

8.2 Eclampsia (studies with quasi‐random allocation)

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

9 Gestational age at birth Show forest plot

2

351

Mean Difference (IV, Fixed, 95% CI)

1.01 [0.56, 1.46]

9.1 Studies with random allocation

2

351

Mean Difference (IV, Fixed, 95% CI)

1.01 [0.56, 1.46]

9.2 Studies with quasi‐random allocation

0

0

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

10 Birthweight Show forest plot

3

451

Mean Difference (IV, Fixed, 95% CI)

91.83 [11.55, 172.11]

10.1 Studies with random allocation

3

451

Mean Difference (IV, Fixed, 95% CI)

91.83 [11.55, 172.11]

10.2 Studies with quasi‐random allocation

0

0

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

11 Length of stay in hospital‐neonatal Show forest plot

1

181

Mean Difference (IV, Fixed, 95% CI)

1.30 [‐0.28, 2.88]

11.1 Studies with random allocation

1

181

Mean Difference (IV, Fixed, 95% CI)

1.30 [‐0.28, 2.88]

11.2 Studies with quasi‐random allocation

0

0

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 1. Any antioxidants versus control or placebo
Comparison 2. Any antioxidants versus control or placebo (sensitivity analyses based on trial quality)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia Show forest plot

3

734

Risk Ratio (M‐H, Fixed, 95% CI)

0.51 [0.32, 0.80]

1.1 High‐quality studies (Allocation concealment = A, blinding, < 3% exclusions and use of placebo)

3

734

Risk Ratio (M‐H, Fixed, 95% CI)

0.51 [0.32, 0.80]

2 Preterm birth (< 37 weeks) Show forest plot

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.40 [1.02, 1.93]

2.1 High‐quality studies (Allocation concealment = A, blinding, < 3% exclusions and use of placebo)

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.40 [1.02, 1.93]

3 Small‐for‐gestational age Show forest plot

2

534

Risk Ratio (M‐H, Fixed, 95% CI)

0.65 [0.47, 0.89]

3.1 High‐quality studies (Allocation concealment = A, blinding, < 3% exclusions and use of placebo)

2

534

Risk Ratio (M‐H, Fixed, 95% CI)

0.65 [0.47, 0.89]

4 Stillbirth Show forest plot

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.00 [0.18, 5.76]

4.1 High‐quality studies (Allocation concealment = A, blinding, < 3% exclusions and use of placebo)

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.00 [0.18, 5.76]

5 Neonatal death Show forest plot

1

181

Risk Ratio (M‐H, Fixed, 95% CI)

0.69 [0.12, 4.03]

5.1 High‐quality studies (Allocation concealment = A, blinding, < 3% exclusions and use of placebo)

1

181

Risk Ratio (M‐H, Fixed, 95% CI)

0.69 [0.12, 4.03]

Figures and Tables -
Comparison 2. Any antioxidants versus control or placebo (sensitivity analyses based on trial quality)
Comparison 3. Any antioxidants versus control or placebo (subgroups by risk status)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia Show forest plot

7

6082

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.50, 0.75]

1.1 Moderate/low‐risk women

4

5572

Risk Ratio (M‐H, Fixed, 95% CI)

0.66 [0.53, 0.83]

1.2 Moderate/high‐risk women

3

510

Risk Ratio (M‐H, Fixed, 95% CI)

0.44 [0.27, 0.71]

2 Preterm birth Show forest plot

3

583

Risk Ratio (M‐H, Fixed, 95% CI)

1.38 [1.04, 1.82]

2.1 Moderate/low‐risk women

1

200

Risk Ratio (M‐H, Fixed, 95% CI)

1.43 [1.03, 1.99]

2.2 Moderate/high‐risk women

2

383

Risk Ratio (M‐H, Fixed, 95% CI)

1.29 [0.78, 2.15]

3 Small‐for‐gestational‐age infant Show forest plot

3

634

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.47, 0.87]

3.1 Moderate/low‐risk women

1

251

Risk Ratio (M‐H, Fixed, 95% CI)

0.51 [0.29, 0.91]

3.2 Moderate/high‐risk women

2

383

Risk Ratio (M‐H, Fixed, 95% CI)

0.72 [0.49, 1.04]

4 Stillbirth Show forest plot

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

4.1 Moderate/low‐risk women

2

5221

Risk Ratio (M‐H, Fixed, 95% CI)

0.84 [0.60, 1.19]

4.2 Moderate/high‐risk women

1

283

Risk Ratio (M‐H, Fixed, 95% CI)

0.50 [0.05, 5.49]

5 Neonatal death Show forest plot

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

5.1 Moderate/low‐risk women

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

5.2 Moderate/high‐risk women

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 3. Any antioxidants versus control or placebo (subgroups by risk status)
Comparison 4. Any antioxidants versus control or placebo (subgroups by gestation at entry)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia Show forest plot

7

6082

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.50, 0.75]

1.1 Entered into study < 20 weeks

2

351

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.36, 1.04]

1.2 Entered into study >= 20 weeks

1

100

Risk Ratio (M‐H, Fixed, 95% CI)

0.10 [0.01, 1.86]

1.3 Entered into study both < and >= 20 weeks

4

5631

Risk Ratio (M‐H, Fixed, 95% CI)

0.63 [0.50, 0.79]

2 Preterm birth Show forest plot

3

583

Risk Ratio (M‐H, Fixed, 95% CI)

1.38 [1.04, 1.82]

2.1 Entered into study < 20 weeks

1

100

Risk Ratio (M‐H, Fixed, 95% CI)

1.32 [0.75, 2.31]

2.2 Entered into study >= 20 weeks

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.3 Entered into study both < and >= 20 weeks

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.40 [1.02, 1.93]

3 Small‐for‐gestational age Show forest plot

3

634

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.47, 0.87]

3.1 Entered into study < 20 weeks

2

351

Risk Ratio (M‐H, Fixed, 95% CI)

0.50 [0.29, 0.87]

3.2 Entered into study >= 20 weeks

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

3.3 Entered into study both < and >= 20 weeks

1

283

Risk Ratio (M‐H, Fixed, 95% CI)

0.74 [0.50, 1.08]

4 Stillbirth Show forest plot

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

4.1 Entered into study < 20 weeks

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

4.2 Entered into study >= 20 weeks

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

4.3 Entered into study both < and >= 20 weeks

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

5 Neonatal death Show forest plot

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

5.1 Entered into study < 20 weeks

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

5.2 Entered into study >= 20 weeks

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

5.3 Entered into study both < and >= 20 weeks

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

Figures and Tables -
Comparison 4. Any antioxidants versus control or placebo (subgroups by gestation at entry)
Comparison 5. Any antioxidants versus control or placebo (subgroups according to dose)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia Show forest plot

7

6082

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.50, 0.75]

1.1 High dose (within pharmacological range)

4

710

Risk Ratio (M‐H, Fixed, 95% CI)

0.47 [0.30, 0.75]

1.2 Low dose (below pharmacological range)

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.70 [0.55, 0.90]

1.3 Unspecified

2

351

Risk Ratio (M‐H, Fixed, 95% CI)

0.42 [0.21, 0.81]

2 Stillbirth Show forest plot

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

2.1 High dose (within pharmacological range)

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.00 [0.18, 5.76]

2.2 Low dose (below pharmacological range)

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.58, 1.17]

2.3 Unspecified

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

3 Neonatal death Show forest plot

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

3.1 High dose (within pharmacological range)

1

181

Risk Ratio (M‐H, Fixed, 95% CI)

0.69 [0.12, 4.03]

3.2 Low dose (below pharmacological range)

1

4895

Risk Ratio (M‐H, Fixed, 95% CI)

1.41 [0.84, 2.37]

3.3 Unspecified

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 5. Any antioxidants versus control or placebo (subgroups according to dose)
Comparison 6. Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia Show forest plot

7

6082

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.50, 0.75]

1.1 Antioxidants alone

5

934

Risk Ratio (M‐H, Fixed, 95% CI)

0.54 [0.36, 0.80]

1.2 Antioxidants with other agents

2

5148

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.50, 0.82]

2 Preterm birth (< 37 weeks) Show forest plot

3

583

Risk Ratio (M‐H, Fixed, 95% CI)

1.38 [1.04, 1.82]

2.1 Antioxidants alone

3

583

Risk Ratio (M‐H, Fixed, 95% CI)

1.38 [1.04, 1.82]

2.2 Antioxidants with other agents

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

3 Small‐for‐gestational age Show forest plot

3

634

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.47, 0.87]

3.1 Antioxidants alone

3

634

Risk Ratio (M‐H, Fixed, 95% CI)

0.64 [0.47, 0.87]

3.2 Antioxidants with other agents

0

0

Risk Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

4 Stillbirth Show forest plot

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

4.1 Antioxidants alone

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.00 [0.18, 5.76]

4.2 Antioxidants with other agents

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.58, 1.17]

5 Neonatal death Show forest plot

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

5.1 Antioxidants alone

1

181

Risk Ratio (M‐H, Fixed, 95% CI)

0.69 [0.12, 4.03]

5.2 Antioxidants with other agents

1

4895

Risk Ratio (M‐H, Fixed, 95% CI)

1.41 [0.84, 2.37]

Figures and Tables -
Comparison 6. Any antioxidants versus control or placebo (subgroups by use of antioxidants combined with other agents)
Comparison 7. Any antioxidants versus control or placebo (subgroups according to dietary intake at entry)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pre‐eclampsia Show forest plot

7

6082

Risk Ratio (M‐H, Fixed, 95% CI)

0.61 [0.50, 0.75]

1.1 Deficient dietary intake at trial entry

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.70 [0.55, 0.90]

1.2 Unknown dietary intake at trial entry

6

1061

Risk Ratio (M‐H, Fixed, 95% CI)

0.45 [0.31, 0.66]

2 Stillbirth Show forest plot

3

5504

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.59, 1.17]

2.1 Deficient dietary intake at trial entry

1

5021

Risk Ratio (M‐H, Fixed, 95% CI)

0.83 [0.58, 1.17]

2.2 Unknown dietary intake at trial entry

2

483

Risk Ratio (M‐H, Fixed, 95% CI)

1.00 [0.18, 5.76]

3 Neonatal death Show forest plot

2

5076

Risk Ratio (M‐H, Fixed, 95% CI)

1.33 [0.81, 2.19]

3.1 Deficient dietary intake at trial entry

1

4895

Risk Ratio (M‐H, Fixed, 95% CI)

1.41 [0.84, 2.37]

3.2 Unknown dietary intake at trial entry

1

181

Risk Ratio (M‐H, Fixed, 95% CI)

0.69 [0.12, 4.03]

Figures and Tables -
Comparison 7. Any antioxidants versus control or placebo (subgroups according to dietary intake at entry)