Utility of amniocentesis in afebrile women with preterm labor

Abstract

Objectives: To determine 1) the rate of positive markers of intraamniotic infection (IAI) in women with preterm labor (PTL) undergoing amniocentesis (AMNIO), 2) the outcomes of pregnancies with positive markers of IAI, 3) whether management was altered based on results, and 4) the rate of rupture of membranes (ROM) following AMNIO. Study design: Our policy was to perform AMNIO on afebrile women with PTL if there was 1) no response to tocolysis, 2) maternal/fetal signs of IAI, or 3) advanced cervical dilation (> 3 cm, ACD), or if fetal lung maturity (FLM) needed to be checked. Cases were identified from 1998 to 1999 by ICD-9 codes. Cases were excluded for fever or ROM before AMNIO. Results: Of the 65 women who were included, 63% received antibiotics before the AMNIO. The mean gestational age (GA) at AMNIO was 33.1 weks, and the mean GA at delivery was 34.1 weeks. The primary indications for AMNIO were FLM (52%), no response to tocolysis (26%), maternal signs (18%), and ACD (1.5%). There were 2 positive cultures (3%), 2 positive Gram stains (3%), 8 patients with white blood cell count of more than 50/uL (12%), 13 patients with glucose less than 15 (20%), and 24 patients with glucose less than 20 (37%). Only glucose less than 15 was associated with positive cultures ( P = 0.04). No positive marker of IAI was associated with abruption, meconium, clinical chorioamnionitis, respiratory distress syndrome, or sepsis. Management was changed based on AMNIO results in 25 cases (39%). ROM followed AMNIO in 14% (mean 1.7 days, maximum 4 days). If ROM occurred, 66% delivered within 48 hours. Conclusions: The rate of IAI was low, and no marker of IAI was associated with neonatal morbidity. These findings may be a result of our use of antibiotics before AMNIO, our culture technique, or changes in obstetric management based on our findings. The 14% risk of ROM was higher than expected. The role of AMNIO in PTL is unclear. A randomized controlled trial is needed to address efficacy and safety of AMNIO in PTL in afebrile women.