The maternal factors associated with infant low birth weight: an umbrella review

Table 3 The credibility of the evidence for included meta-analyses

Risk factors	Random effects P-value	Number of cases	Excess of significance bias (p-value) ESB	the value of the pooled effect size expressed in equivalent Hedges’ g (eG)	small-study effects (p-value for Egger	Prediction Intervals	Largest study (95% CI)	Heterogeneity (I2%)	Classification
crack cocaine	< 0.001	1072	0.435	0.572	0.645	1.699–4.689	2.098–3.228	25.433	Class I
Infertility	< 0.001	7770	0.629	0.16	0.816	1.148, 1.556	0.769, 2.1	0	Class I
smoking	< 0.001	15,413	0.443	0.383	0.495	1.131–3.543	1.251–1.75	66.136	Class II
antenatal Care	< 0.001	1211	0.882	0.411	0.481	0.586–1.339	0.329–0.489	55.79	Class II
Periodontal	< 0.001	7202	0.002	0.485	0.006	0.599–9.702	0.891–1.561	81.892	Class III
Depression	< 0.001	6244	< 0.001	0.338	0.01	0.638–5.337	1.224–2.313	81.275	Class III
anemia	< 0.001	9394	< 0.001	0.154	0.02	0.752–2.324	1.15–7.62	65.679	Class III
caffeine/coffee	< 0.001	5072	0.246	0.16	0.071	0.872, 2.046	1.017, 2.018	52.90	Class III
heavy physical workload	0.048	12,794	0.014	0.344	0.05	0.225–15.494	2.122–3.432	91.388	Class IV
underweight	0.002	9625	0.12	0.29	0.147	0.433–6.621	1.085–1.336	86.144	Class IV
lifting ≥ 11 kg	0.042	1891	0.8	0.255	0.253	0.323–7.808	1.302–4.421	81.955	Class IV
alcohol	0.001	30,444	0.004	0.114	0.619	0.48–3.146	0.581–1.579	89.166	Class IV
hypothyroidism	0.045	1122	0.468	0.184	0.603	0.66, 2.955	0.819, 1.76	21.53	Class IV
Hypertension	< 0.001	479	0.253	0.75	0.924	1.083, 14.038	1.789, 40.869	75.07	Class IV
overweight/obesity	0.054	9625	0.005	0.084	0.334	0.733–1.854	1.303–1.722	63.421	NS

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