Perineal length: norms in gravid women in the first stage of labour.
BACKGROUND
The purpose of this study was to generate normative data for perineal length for Caucasian and Asian women in labour.


METHODS
The distance from the posterior fourchette to the centre of the anal orifice was measured in 1,000 women in the first stage of labour. Data on ethnicity, body mass index, delivery mode and perineal trauma were collected prospectively.


RESULTS
The mean perineal length in Caucasian women was 3.7 +/- 0.9 cm and in Asian women, 3.6 +/- 0.9 cm. Primigravid women with short perineum were more likely to have a third-degree perineal tear in labour (p = 0.03).


CONCLUSIONS
This is the first paper to report normative data for perineal length in Caucasian and Asian women in labour. We found a negative correlation between perineal length and third-degree tear in primigravid women. These data may be useful in clinical practice to determine the risk of significant perineal tears in labour.
Dua
Anupreet
A
Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK.
Whitworth
Melissa
M
Dugdale
Annette
A
Hill
Simon
S
D000328:Adult; D044466:Asian People / Q000208:ethnology*; D005260:Female; D006801:Humans; D007747:Labor Stage, First / Q000502:physiology*; D022125:Lacerations / Q000453:epidemiology / Q000208:ethnology; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000208:ethnology; D010502:Perineum / Q000033:anatomy & histology*; D011247:Pregnancy / Q000502:physiology*; D011446:Prospective Studies; D012307:Risk Factors; D044465:White People / Q000208:ethnology*