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When is the post-coital test normal? A critical appraisal
S G Oei1, F M Helmerhorst, M J Keirse
1Department of Obstetrics, Gynaecology and Reproductive Medicine, Leiden University Hospital, The Netherlands.
Human Reproduction (Oxford, England)
|July 1, 1995
Summary
The post-coital test (PCT) has poor predictive power for pregnancy. Defining an abnormal PCT as less than one motile sperm per field improves specificity but doesn't significantly enhance its diagnostic value.
Area of Science:
- Reproductive Endocrinology
- Infertility Diagnostics
- Clinical Epidemiology
Background:
- The post-coital test (PCT) is used to assess cervical mucus-sperm interaction.
- Its predictive value for achieving pregnancy remains debated.
- Optimal criteria for defining an abnormal PCT are not well-established.
Purpose of the Study:
- To systematically review studies evaluating the relationship between PCT results and pregnancy.
- To determine the predictive power of the PCT.
- To establish a definition of abnormality with optimal test characteristics.
Main Methods:
- Systematic review of published studies.
- Inclusion criteria: well-defined PCT results and valid pregnancy outcome data.
- Analysis of 11 studies involving 3093 women attending fertility clinics.
Main Results:
- PCT predictive values for normal and abnormal results ranged from 0.37-0.92 and 0.58-0.85, respectively.
- Sensitivity and specificity varied widely (0.10-0.90 and 0.30-0.97).
- Likelihood ratios for normal and abnormal PCT were 0.77 and 1.85, respectively. Lowering the threshold for normal sperm count increased specificity but decreased sensitivity.
Conclusions:
- The PCT demonstrates poor discriminating ability for predicting pregnancy.
- Altering definitions of normality minimally improves its predictive power.
- An abnormal PCT is best defined as fewer than one motile spermatozoon per high power field to maximize specificity and likelihood ratio for abnormal results, despite overall poor test performance.