Amniotic Fluid Particles and Optical Density at Term - A Case Report

摘要

We report a case of pregnancy at full term and transabdominal ultrasonography (USG) revealed minute amniotic fluid particles prior to onset of spontaneous labor. Amniotic Fluid Optical Density (AFOD) estimation for fetal lung maturity was done. AFOD was 0.43 in uncentifuged and 0.14 in centrifuged samples at 650 nm. USG at onset of labor detected amniotic fluid particles of 3-4 mm size corresponding to AFOD of 1.40 (uncentrifuged sample) at ARM. The rapid increase in the size of the echogenic amniotic fluid particles simultaneously with optical density may be able to serve as an index of physiological process that contributes to the onset of labor. Introduction Previous studies of fetal lung maturity vary from ability to read news prints across test tubes containing Amniotic Fluid to quantitative LS ratio estimation 1. Cetrulo et al concluded that centrifuged amniotic fluid samples with optical density of 0.15 and above corresponds to fetal lung maturity 2. Narendran et al studied the lung skin interactions that causes the rise in turbidity of Amniotic Fluid. The pulmonary surfactant causes vernix detachment. Simultaneously there is a surge in sebaceous gland activity 3. Also amniotic fluid cells (fetal corneocytes / sebocytes) are able to produce cytokines like IL-1,IL-6,IL-8 which contribute the onset of labor 45678910. Sonological studies have shown that AF particles in third trimester are nothing but vernix (100 % sensitivity) and less likely due to meconium but the possibility of meconium stained liquor cannot be ruled out fully 1112. Although there is no definitive ideal sonological marker for fetal lung maturity the assessment of echogenic amniotic fluid particles can contribute towards non invasive estimation of fetal lung maturity culminating in onset of Labor. Case Report A 28 yr old primigravida with reliable dates of LMP (confirmed by CRL and BPD measurements in first and second trimester), no co-morbidities, on regular antenatal checkups presented for follow-up in OPD at 40wks 3days of gestational age. Bishop score was unfavourable.Transabdominal USG evaluation was done. Placenta had grade 2 maturity and AFI was 13 cms. Biophysical Profile was normal. Numerous wandering minute flakes of AF particles were detected in the deepest vertical pool of amniotic fluid (Figure 1a). 2ml of amniotic fluid was obtained from the most superficial AF pocket under continuous USG guidance 13 with 2cc syringe and 23G needle for assessment of fetal lung maturity. Prior written informed consent was taken as per declarations of Helsinki. The procedure was uneventful. Uncentifuged fresh amniotic fluid sample thus obtained had an AFOD of 0.43 at 650 nm (Figure 1b). Centrifuged sample (2000xg) showed AFOD of 0.14 at 650 nm. Newprints read across the test tube containing sample of AF appeared blurred.