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2020 (English)In: BMC Pregnancy and Childbirth, ISSN 1471-2393, E-ISSN 1471-2393, Vol. 20, no 1, article id 749Article in journal (Refereed) Published
Abstract [en]
Background: The aim of this study was to estimate the incidence of second-degree perineal tears, obstetric anal sphincter injuries (OASI), and high vaginal tears in primiparous women, and to examine how sociodemographic and pregnancy characteristics, hereditary factors, obstetric management and the delivery process are associated with the incidence of these tears.
Methods: All nulliparous women registering at the maternity health care in Region Örebro County, Sweden, in early pregnancy between 1 October 2014 and 1 October 2017 were invited to participate in a prospective cohort study. Data on maternal and obstetric characteristics were extracted from questionnaires completed in early and late pregnancy, from a study-specific delivery protocol, and from the obstetric record system. These data were analyzed using unadjusted and adjusted multinomial and logistic regression models.
Results: A total of 644 women were included in the study sample. Fetal weight exceeding 4000 g and vacuum extraction were found to be independent risk factors for both second-degree perineal tears (aOR 2.22 (95% CI: 1.17, 4.22) and 2.41 (95% CI: 1.24, 4.68) respectively) and OASI (aOR 6.02 (95% CI: 2.32, 15.6) and 3.91 (95% CI: 1.32, 11.6) respectively). Post-term delivery significantly increased the risk for second-degree perineal tear (aOR 2.44 (95% CI: 1.03, 5.77), whereas, maternal birth positions with reduced sacrum flexibility significantly decreased the risk of second-degree perineal tear (aOR 0.53 (95% CI 0.32, 0.90)). Heredity of pelvic floor dysfunction and/or connective tissue deficiency, induced labor, vacuum extraction and fetal head circumference exceeding 35 cm were independent risk factors for high vaginal tears (aOR 2.32 (95% CI 1.09, 4.97), 3.16 (95% CI 1.31, 7.62), 2.53 (95% CI: 1.07, 5.98) and 3.07 (95% CI 1.5, 6.3) respectively).
Conclusion: The present study corroborates previous findings of vacuum extraction and fetal weight exceeding 4000 g as risk factors of OASI. We found that vacuum extraction is a risk factor for second-degree tear, and vacuum extraction, fetal head circumference exceeding 35 cm and heredity of pelvic floor dysfunction and/or connective tissue deficiency were associated with increased risk of high vaginal tears. These findings have not been documented previously and should be confirmed by additional studies.
Place, publisher, year, edition, pages
BioMed Central, 2020
Keywords
High obstetric vaginal tear, Obstetric anal sphincter injuries, Perineal tears, Risk factors, Second-degree perineal tears
National Category
Obstetrics, Gynecology and Reproductive Medicine
Identifiers
urn:nbn:se:oru:diva-87789 (URN)10.1186/s12884-020-03447-0 (DOI)000597976100002 ()33267813 (PubMedID)2-s2.0-85096961645 (Scopus ID)
Funder
Swedish Society of Medicine, SLS250351
Note
Funding Agencies:
ALF funding Region Örebro County OLL-839631 OLL-930507
Region Örebro County Research Committee OLL-779831
Örebro University Hospital Research Foundation OLL410421
2020-12-032020-12-032022-04-27Bibliographically approved