Methods: Seventy primagravida and 40 nulliparous women participated voluntarily in the study. An oral examination of the subjects was done to score gingival and plaque indices, bleeding upon probing (BOP) and clinical pocket depths (CPD) from four aspects of whole dentition. Subgingival plaque samples were obtained from sites showing signs of gingivitis as well as from healthy sites. A method for detection of 7 types of periodontopathogens and 2 types of early colonizers using agarose gel electrophoretic analysis of specific bacterial sequences of DNA extracted from plaque samples and amplified by PCR was employed.
Results: Pregnant subjects harbored C. rectus, T. forsythia, T. denticola in a higher rate in gingivitis lesions in comparison with their healthy sites (p<0,01, P<0,01, p<0,05). Pregnant group's gingivitis lesions harbored P. intermedia and P. gingivalis at a higher rate than in control group (p<0,01, p<0,05) whereas A. actinomycetemcomitans was found at a lower rate (p<0,01), healthy sites harbored P. intermedia and P. gingivalis at a higher rate than in control group (p<0,01) and A. actinomycetemcomitans was found at a higher frequency than in control group (p<0,05). BOP was found higher in A. actinomycetemcomitans negative healthy sites of pregnant women than in A. actinomycetemcomitans positive healthy sites (p<0,05). S. sanguinis negative healthy sites showed higher BOP and CPD than in positive sites (p<0,01, p<0,05). Preterm labor was higher in women having P. intermedia negative healthy sites than in positive healthy sites (p<0.05).
Conclusion: It was found that absence of P. intermedia increased the risk of preterm labor 10 times.