Vaginal microbiome analysis of healthy women during different periods of gestation
Authors: He-Qin Yang
Qin-Ping Liao
Jing-Rong Cao
Xiao-Yan Sun
Xin-Zuo Chi
Dan Li
Rui Chen
Lei Zhang
Journal: Bioscience Reports (2020)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: lactobacillus; longitudinal studies; pregnancy; vaginal microbiome.
Affiliations: Department of Obstetrics and Gynecology, Xuan Wu Hospital, Capital Medical University, Beijing 100053, China., Department of Obstetrics and Gynecology, Beijing Tsinghua Chang Gung Hospital, Beijing 102218, China., Department of Clinincal Laboratory, Xuan Wu Hospital, Capital Medical University, Beijing 100053, China.

Abstract:  To assess the vaginal microbiome throughout full-term uncomplicated pregnancy, a longitudinal study was designed for 12 healthy women who had prepared to become pregnant and then delivered at term (38-42 weeks) without complications. The vaginal microbial community was studied at pre-pregnancy, 8-12, 24-28, 37-38 weeks of gestation, and puerperium, using hypervariable tag sequencing of the V3-V4 region of the 16S rRNA gene. Sequencing produced approximately 10 million reads on the Illumina MiSeq. Members of the Firmicutes phyla were prevailing before and during pregnancy periods, and the proportion was quite as Proteobacteria until puerperium. Lactobacillus genus was abundant before and during pregnancy, but post-delivery vaginal microflora variety turned diverse. The species-level analysis revealed that a healthy vaginal microbiome before or during pregnancy was prominently dominated by Lactobacillus crispatus. Furthermore, PCoA analysis revealed for differences in the bacterial community composition between the two levels of Lactobacillus species in pre-pregnancy and pregnancy period (PC1 contribution of 58.46%, PC3 contribution of 8.64%). Based on the taxonomic and PCoA analysis, we found that L. crispatus was dominant in the vaginal microflora of healthy women before or during pregnancy, but at the puerperium, the status changed leading to decreased abundance of protective Lactobacillus species that made vaginal micro-ecological barrier vulnerable to diseases. Additionally, vaginal pH was an important environmental property affecting the vaginal microbial community. 

Retracted: No

PubPeer comments:
 u201d There are very few studies, especially in women of *the yellow race* in China, for the complete pregnancy period, a longitudinal study that also included the pre-pregnancy period.u201d (Emphasis added) While cultural norms differ around the world, the phrase u201cthe yellow raceu201d would be considered inappropriate in most u201cinternationalu201d journals. Iu2019m surprised that this wasnu2019t flagged by the peer reviewers or editors. Elsewhere in this paper the descriptor u201cHan nationality,u201d is used, which seems more appropriate. , 
 #1 They could be referring to Mongolian people, which in Chinese is u9ec4u79cd, directly translating to  yellow race , 
 #2 As I mentioned, the population they studied were also identified in the paper as being of Han nationality, so I donu2019t think that the Mongolian ethnic minority is what is meant here. There may be reasons that the majority-Han ethnic group in China may use or even prefer the phrase u201cthe yellow raceu201d (I am aware of some), however English-speakers outside of China may be more sensitive to this phrasing. , 
 The authors of the original paper u201cVaginal microbiome analysis of healthy women during different periods of gestationu201d (Biosci Rep. (2020), 40(7), DOI: 10.1042 BSR20201766), would like to correct the following statement from the last paragraph of the introduction in their paper: u201cThere are very few studies, especially in women of the yellow race in China, for the complete pregnancy period, a longitudinal study that also included the pre-pregnancy period.u201d Which should have read; u201cThere are very few studies, especially in women of the Han nationality in China, for the complete pregnancy period, a longitudinal study that also included the pre-pregnancy period.u201d The Journal and the authors apologise for this error and for any offence caused. ,