Table 4.
Characteristics of studies included in the meta analysis.
| Refs. | Year | Country | Population | PPROM Excluded | SPTB Cases Criteria | Case Sample Size | Control Criteria | Control Group Size |
|---|---|---|---|---|---|---|---|---|
| this study | 2017 | Slovenia | Caucasian | no | GA <37 | 98 | GA >37 | 135 |
| [30] | 2013 | Korea | Asian | no | GA <37 | 166 | GA >37 | 289 |
| [31] | 2004 | Hungary | Caucasian | no | GA <37 | 32 | GA >37 | 127 |
| [33] | 2002 | Turkey | Caucasian | yes | GA <37 | 80 | GA >37 | 76 |
| [32] | 2002 | USA | Hispanic | no | GA <37 | 28 | GA >37 | 251 |
PPROM: preterm premature rupture of the membranes; SPTB: spontaneous preterm birth; GA: gestational age.