ANGIOGENIN - A MARKER FOR PRETERM DELIVERY IN MIDTRIMESTER AMNIOTIC-FLUID

OBJECTIVE: Neovascularization is a response of tissue to ischemic dama ge. Placental ischemia is thought to underlie a significant portion of preterm deliveries. Our objective was to evaluate whether angiogenin, a potent inducer of neovascularization, is increased in midtrimester amniotic fluid of patients destined to be delivered preterm. STUDY DES IGN: We designed a case-control study of singleton gestations undergoi ng midtrimester amniocentesis for standard genetic indications. Inclus ion criteria were (1) pregnancy outcome information available, (2) ges tational age at amniocentesis 15 to 20 weeks, (3) no evidence of fetal structural or chromosomal anomalies, and (4) absence of conditions as sociated with preterm delivery. Amniotic fluid angiogenin levels were measured by immunoassay and normalized by natural log transformation f or statistical analysis. RESULTS: Eleven patients with preterm deliver ies were matched with 33 controls. Amniotic fluid angiogenin levels we re significantly higher in patients with preterm deliveries compared w ith controls (median 30.1 ng/ml [range 13.6 to 71.0 ng/ml] vs 17.8 ng/ ml [7.8 to 43.3 ng/ml], p = 0.002). Demographic data were not signific antly different. The association between angiogenin levels and preterm delivery persisted after small-for-gestational-age neonates were excl uded (p = 0.02). Receiver-operator characteristic curve analysis showe d that an angiogenin level of 31.0 ng/ml was the optimal cutoff point for prediction of preterm delivery (sensitivity 45.5%, specificity 91. 0%, p = 0.03, odds ratio 6.0). CONCLUSIONS: Midtrimester amniotic flui d angiogenin levels are elevated in patients with preterm delivery. Th is supports the theory that preexisting intrauterine ischemia and infl ammation are important risk factors for preterm delivery and may be al ready present in the early midtrimester.