Journal of Obstetrics and Gynaecology, April 2015; 35: 235–240 © 2015 Informa UK, Ltd. ISSN 0144-3615 print/ISSN 1364-6893 online DOI: 10.3109/01443615.2014.958143

OBSTETRICS

Mean gestation at delivery and histological chorioamnionitis correlates with early-onset neonatal sepsis following expectant management in pPROM P. Arora1, R. Bagga1, J. Kalra1, P. Kumar2, S. Radhika3 & V. Gautam4

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Departments of 1Obstetrics and Gynaecology, 2Neonatology, 3Gynae-Pathology and Cytology, and 4Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India

This prospective observational study was carried out in India among 100 women with preterm pre-labour rupture of membranes (pPROM) between 260/7–330/7 weeks on expectant management in order to correlate early-onset neonatal sepsis (EONS) with various features of chorioamnionitis. The incidence of pPROM during the study period of 1.5 years was 7%. The mean gestation at pPROM was 306/7 ⴞ 1.8 weeks and at delivery was 321/7 ⴞ 1 weeks. Features of chorioamnionitis in the form of clinical, microbiological, histological or a combination of these were observed in 70/100 women. Clinical chorioamnionitis was seen in 16%, bacterial isolates were present in 30% on cervical swab and in 39% on placental membrane culture and 19% had histological chorioamnionitis. EONS was present in 23/97 (24%). Clinical chorioamnionitis (p ⴝ 0.069), bacterial isolates on cervical swab (p ⴝ 0.56) or placental membranes (p ⴝ 0.39) were not found to predict EONS; whereas histological chorioamnionitis (p ⴝ 0.002) and lower gestation at delivery (p ⴝ 0.013) were significantly associated with EONS. Keywords: Clinical chorioamnionitis, EONS, expectant management, histological chorioamnionitis, microbiological chorioamnionitis, pPROM

Introduction Preterm pre-labour rupture of membranes (pPROM) occurs in 3% of pregnancies and accounts for 40% of preterm births (Canavan et al. 2004). Expectant management is the standard of care in pPROM in order to reduce neonatal risks due to prematurity. The resultant increased infectious morbidity may be lowered with antibiotics (chorioamnionitis, RR 0.57; neonatal infection, RR 0.68) (RCOG 2010). Chorioamnionitis is diagnosed clinically, by amniotic fluid culture and histopathology of the placenta. Although not included among the standard diagnostic criteria for chorioamnionitis, cervical/vaginal swab cultures during expectant management or placental membrane culture after delivery have been reported as microbiological evidence of chorioamnionitis (Carroll et al. 1996; Berger et al. 2004). Amniotic fluid obtained by amniocentesis is subjected to Gram stain, biochemistry, cytokine assay and culture to diagnose intra-amniotic infection (Newton 1993). However, routine amniocentesis to diagnose intra-amniotic infection is

not recommended, as it remains to be determined whether it improves outcomes (RCOG 2010). Also, intra-amniotic infection may be a cause rather than a consequence of amniorrhexis (Carroll et al. 1995). The sensitivity of vaginal swab, total leucocyte count (TLC) or C-reactive protein to detect intrauterine infection is low (RCOG 2010). Literature from developing countries about expectant management in pPROM is limited and the risk of infectious morbidity is much higher compared with developed countries (Furman et al. 2000; Melamed et al. 2009; Osmanagaoglu et al. 2005). The present study was carried out in a tertiary care hospital in North India, among 100 women with pPROM on expectant management, to see which feature of chorioamnionitis correlates best with EONS.

Materials and methods This study was conducted in the Post Graduate Institute of Medical Education and Research, Chandigarh, India from July 2009 to December 2010. Women from 260/7 to 330/7 weeks with pPROM (n ⫽ 100) were included after informed consent. Expectant management was offered in the absence of chorioamnionitis and fetal distress (reactive non-stress test (NST), absence of meconium stained amniotic fluid and abruptio). Women with medical disorders, multiple pregnancy, placenta praevia, HIV, hepatitis B or C infection, fetal growth restriction or malformations were excluded. Gestational age was confirmed by sonography ⬍ 20 weeks. The diagnosis of pPROM was made by history plus any two of the following: (1) demonstration of amniotic fluid leaking through the cervix or pooling in the vagina; (2) positive Nitrazine test (pH of fluid ⬎ 7.1); (3) presence of delicate arborisation on an air dried smear of vaginal fluid; and (4) amniotic fluid index (AFI) ⬍ 5 on sonography. A cervical swab was collected for bacterial culture and antibiotic susceptibility. The women received standard care, which included betamethasone (12 mg i.m., 2 doses, 24 h apart); ampicillin (2 g i.v. 6 hourly for 48 h), followed by amoxicillin (500 mg p.o. 8-hourly for 5 days) and erythromycin (333 mg p.o. 8-hourly for 7 days). Fetal surveillance included daily fetal movement count, twice weekly biophysical profile and NST. Maternal monitoring included daily examination for uterine tenderness or malodorous/purulent vaginal discharge, pulse and temperature 8-hourly, TLC/differential

Correspondence: R. Bagga, Department of Obstetrics and Gynaecology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India. E-mail: [email protected]

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leucocyte count (DLC) twice weekly and cervical swab culture weekly. Clinical chorioamnionitis was diagnosed in the presence of fever ⱖ 38°C (100.4°F) plus any two of the following: leucocytosis (TLC ⬎ 15,000 cells/mm3); maternal tachycardia (⬎ 100/ min); fetal tachycardia (⬎ 160/min); uterine tenderness; or malodorous vaginal discharge (Newton 1993). Expectant management was terminated in the presence of clinical chorioamnionitis, non-reassuring fetal status, placental abruption, onset of labour or completion of 34 weeks. The placenta and membranes were collected for bacterial culture and histopathology. Histological chorioamnionitis was defined as the presence of ⬎ 10 neutrophils/HPF at ⱖ 2 sites in the chorionic plate and extra-placental membranes. Any feature of funisitis was noted. The neonates were monitored for evidence of sepsis until 72 hrs of life. A sepsis screen was performed if there were signs or symptoms of EONS. A positive blood culture within 72 hrs was defined as ‘proven early-onset sepsis’. A positive sepsis screen or chest X-ray suggestive of pneumonia was defined as ‘probable early-onset sepsis.’ If the neonate had signs of sepsis (lethargy, poor feeding or tachypnoea), but the sepsis screen and blood culture were negative, it was considered to have ‘possible early-onset sepsis.’ The sepsis screen included absolute neutrophil count, band cell count, C reactive protein, micro-ESR and gastric aspirate polymorphs. The cut-off values for a positive test were:

absolute neutrophil count below or above the reference values; CRP ⱖ 1:2 dilution estimated semi-quantitatively (latex agglutination); ratio of immature to mature neutrophils ⬎ 0.20; gastric aspirate with ⱖ 35% of neutrophils/100 cells or ⬎ 5 neutrophils/ HPF; and micro ESR ⬍ 95th percentile. Any two positive tests constituted a positive sepsis screen. Data analysis was performed with software (SPSS, version 15.0; SPSS Inc, Chicago). The Student’s t-test was used to compare continuous variables between groups and the χ2-test was used for categorical variables. Multivariate logistic regression analysis was used to identify factors that were associated with EONS. Relative risk was estimated based on the odds ratio (OR) using the Zhang and Yu method. Differences were considered significant when the p ⱕ 0.05.

Results During the study period of 1.5 years, a total of 383 women with pPROM were admitted to the labour ward. Of these, 100 women who fulfilled the inclusion criteria were recruited (Figure 1). The incidence of pPROM during this period was 7% (383/5,191 deliveries). The mean age was 26.29 ⫾ 3.92 years (range 20–37 years); 48/100 were nulliparous and 20% had a history of a prior preterm birth due to spontaneous preterm labour or pPROM. The mean

Total number of women with pPROM during the study period from 1 July 2009 to 31 July 2010 (n = 383)

Fulfilled inclusion criteria and enrolled for the study

Excluded (n = 283) • • • • • • • • •

Gestation >33 weeks,

Mean gestation at delivery and histological chorioamnionitis correlates with early-onset neonatal sepsis following expectant management in pPROM.

This prospective observational study was carried out in India among 100 women with preterm pre-labour rupture of membranes (pPROM) between 26(0/7)-33(...
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