Table 3: Clinical characteristics of examined groups in the first (I) and second (II) periods.

GroupPeriodSerial dosesSingle dosesControl
N(%)N(%)N(%)

CervicalI43(31%)17(12%)21(13%)
cerclageII20(14%) 5(5%)20(11%)
SpontaneousI116(83%)86(61%)54(39%)
birthII101(71%)82(82%)142(78%)
CesareanI21(13%)63(39%)63(39%)
sectionII32(23%)25(25%)38(21%)