Alpha-fetoprotein as a tool to distinguish amniotic fluid from urine, vaginal discharge, and semen

Amir Mor, Reshef Tal, Shoshana Haberman, Sandra Mccalla, Mohamad Irani, Jaqueline Perlman, David B. Seifer, Howard Minkoff

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


OBJECTIVE:: To estimate whether alpha-fetoprotein (AFP) can be used to distinguish amniotic fluid absorbed in sanitary pads from other similarly absorbed substances (semen, urine, and normal vaginal discharge). METHODS:: A prospective cohort study. Urine and amniotic fluid specimens were collected from 52 pregnant women admitted for labor. Semen specimens were collected from 17 men undergoing infertility evaluation. Alpha-fetoprotein concentrations were measured directly from urine, amniotic fluid, and semen and from pads instilled with samples from these specimens. Alpha-fetoprotein concentrations were also measured from pads absorbed with normal vaginal discharge collected from 27 pregnant women. RESULTS:: Alpha-fetoprotein levels in amniotic fluid (245.38±21.03 ng/mL, n=52) were significantly higher than those measured in maternal urine (0.84±0.17 ng/mL, n=52, P<.001), or semen (1.52±0.35 ng/mL, n=17, P<.001). The same trend was seen when AFP was extracted from pads: amniotic fluid levels (19.44±1.98 ng/mL, n=52) were significantly higher than those of urine (undetectable, n=52), semen (undetectable, n=17), or normal vaginal discharge (0.53±0.16 ng/mL, n=27, P<.001). Receiver operator characteristic curve analysis demonstrated 96.2% sensitivity and 100% specificity for distinguishing the presence of amniotic fluid from normal vaginal discharge on sanitary pads (cutoff 3.88 ng/mL, area under the curve 0.99). CONCLUSION:: When the diagnosis of rupture of membranes is in doubt, AFP levels can assist in differentiating amniotic fluid from other bodily fluids. A method that utilizes sanitary pads and an assay for AFP quantification may be an accurate and convenient way to confirm the diagnosis of rupture of membranes.

Original languageEnglish (US)
Pages (from-to)448-452
Number of pages5
JournalObstetrics and gynecology
Issue number2
StatePublished - Feb 6 2015
Externally publishedYes

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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