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Infectious Diseases in Obstetrics and Gynecology
Volume 3, Issue 5, Pages 179-183
Clinical Study

Amniotic-fluid Lactoferrin: A Marker for Subclinical Intraamniotic Infection Prior to 32 Weeks Gestation

1Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, USA
2Department of Obstetrics and Gynecology, Duke University, Durham, NC, USA
3Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Hospital, 300 Halket Street, Pittsburgh, PA 15213, USA

Received 16 December 1995; Accepted 24 January 1996

Copyright © 1995 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective: Lactoferrin is a glycoprotein released from the secondary granules of activated neutrophils in the setting of infection. The purpose of this study was to determine if amniotic-fluid (AF) lactoferrin levels are elevated in preterm labor (PTL) patients with subclinical intraamniotic infection (IAI).

Methods: AF samples were obtained from 186 pregnant patients with the following characteristics: group 1 - term, no labor; group 2 - preterm, no labor; group 3 - PTL with IAI; group 4 - PTL without IAI. Lactoferrin levels were measured with an enzyme-linked immunosorbent assay (ELISA).

Results: AF lactoferrin levels were elevated in normal gestation after 31 weeks (P < 0.0001). Lactoferrin levels were also higher in infected PTL patients compared with noninfected PTL patients at gestations ≤31 weeks (P = 0.005). An AF lactoferrin level of >2.5 μg/ml is highly suggestive of infection in PTL patients at <32 weeks, with an overall sensitivity of 82% and a specificity of 83%, when infection is defined as a positive AF culture or positive placental histology.

Conclusions: AF lactoferrin levels increase after 31 weeks in normal gestations, but lactoferrin levels >2.5 μg/ml in PTL patients before this gestational age are highly suggestive of IAI. AF lactoferrin levels may be a useful clinical tool for selecting those PTL patients who might benefit from antimicrobial therapy, closer observation, or early delivery.