Table 5 Pooled estimates effect of preconception care

Congenital malformation

11 [10, 16, 19–21, 23, 25, 26, 28, 32, 33]

0.25(0.15,0.42)

Perinatal Mortality

5 [10, 16, 20, 23, 33]

0.35(0.15,0.82)

Macrosomia

3 [10, 20, 23]

1.03(0.81,1.30)

Cesarean Section

5 [10, 16, 20, 21, 23]

1.08(0.96,1.22)

Preterm Delivery

4 [10, 16, 20, 23]

0.7 (0.55,0.90)

Pre-eclampsia

3 [10, 20, 21]

0.92(0.62,1.35)

Neonatal Hypoglycemia

3 [20, 21, 23]

0.65(0.39,1.08)

Maternal Hypoglycemia

2 [10, 28]

1.51(1.15,1.99)

Spontaneous Abortion

7 [10, 15, 20, 23, 25, 26, 32]

0.78(0.55,1.11)

Respiratory Distress Syndrome

3 [20, 21, 23]

0.55(0.26,1.16)

Small for Gestation Age

2 [20, 23]

0.26(0.05,1.41)

Continuous outcomes

Number of studies ( references)

Means difference (95% CI)

The difference in the level of glycosylated Hemoglobin A1c

4 [10, 21, 26, 28]

2.43(2.27,2.58)

The difference in gestational age at first visit to antenatal care

3 [10, 23, 26]

1.32 (1.23, 1.40)