Socio-Behavioral Predictors of Vaginal Lactobacillus Dominance in Pregnant African American Women Open Access

Cutler, Anya (Spring 2018)

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Adverse birth outcomes disproportionately affect African American women compared to women of other races and ethnicities. Socioeconomic and lifestyle factors do not fully explain these racial disparities. Recent advances in bacterial sequencing technology have revealed the importance of Lactobacillus species in maintaining an acidic and stable vaginal microbiome. Vaginal dysbiosis, which occurs most often in African American women, is characterized by low levels of Lactobacillus and high levels of anaerobic bacteria and has been linked to increased risks of sexually transmitted infections, bacterial vaginosis, and preterm birth. This study sought to identify the socioeconomic and behavioral predictors of Lactobacillus dominance and preterm birth among pregnant African American women. 184 women were recruited from a public and private hospital in Atlanta. Vaginal swabs and demographic/lifestyle questionnaires were collected at 8-14 weeks (T1) and 24-30 weeks (T2) gestational age. Hierarchical clustering was performed to characterize a Lactobacillus­­-dominant community state type (L-CST) and a diverse community state type (D-CST) among vaginal microbiome samples. Women had significantly higher levels of Lactobacillus at T2 compared to T1 (p=0.038). Vaginal dysbiosis at T1 was significantly associated with young maternal age, single marital status, and low education, whereas vaginal dysbiosis at T2 was significantly associated with a short cervical length and recent receipt of oral sex. The odds of having a D-CST at T2 was 2.87 (95% CI = 1.014, 8.132) times higher among women who received oral sex in the past month compared to those who did not after controlling for socio and behavioral variables. Additionally, the risk of preterm birth (<36 weeks) and early birth (<38 weeks) was significantly higher among women who transitioned from a L-CST to D-CST microbiome between T1 and T2 compared to women who maintained a L-CST microbiome throughout pregnancy. I concluded that oral sex and short cervical length in late pregnancy may predispose women to vaginal dysbiosis and subsequently cause inflammation and premature rupturing of the amniotic sac. Further work on the relationship between Lactobacillus levels, cervical length, and sexual practices could identify clinical recommendations that would improve vaginal health and decrease preterm birth risk in African American women.  


Table of Contents

Pg. 1.   Background/ Literature Review

Pg. 14. Methods

Pg. 18. Results

Pg. 23. Discussion

Pg. 28. Future Directions

Pg. 29. Refererences

Pg. 43. Tables

Pg. 51. Figures and Figure Legends



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