Fig 1.
Flow diagram of study selection process.
Fig 2.
Forest plot for meta-analysis of the association between maternal passive smoking and the risk of having an infant with NSOFC.
Table 1.
Characteristics of studies of risk of NSOFC in the offspring of non-smoking mothers exposed to passive smoking included in meta-analysis.
Fig 3.
Forest plot for meta-analysis of the association between maternal passive smoking and the risk of having an infant with NSOFC, comparing the different types of maternal smoking exposure (active and passive).
Fig 4.
Forest plot for meta-analysis showing the crude and reported adjusted OR for the association between maternal passive smoking and NSOFC.
Fig 5.
Forest plot for meta-analysis of the association between NSOFC and maternal passive smoking exposure in the 1st trimester including or not including the pregestation period compared to maternal exposure prior to pregnancy period alone.
Fig 6.
Forest plot for meta-analysis of the association between NSOFC phenotype (CL/P and CP) and maternal passive smoking.
Fig 7.
Forest plot for meta-analysis of the association between maternal passive smoking and NSOFC according to region.
Fig 8.
Forest plot for meta-analysis of the association between maternal passive smoking and NSOFC according to study quality (NOS scale).
Table 2.
Univariate meta-regression analysis relating cleft type and study quality to effect size estimates of the relation between passive smoking and NSOFC.
Fig 9.
Funnel plot for studies showing the relationship between passive smoking and both CL/P and CP.