Placental Parameters and Foetomaternal Haemorrhage

Abstract

BACKGROUNDEntry of foetal erythrocytes into maternal circulation before or during delivery is referred as Foetomaternal Haemorrhage (FMH). An Rh-D negative women when exposed to the cells of an Rh-D positive foetus, produces anti-D antibodies that causes complications like foetal anaemia, hydrops foetalis and neonatal jaundice. The Kleihauer-Betke test is a quantitative test, which uses the concept of differential resistance to acid by foetal and adult haemoglobin. As the potential risk factors can be determined by placental morphology and provide information on pregnancy outcome, they may provide information on incidence and amount of FMH also.The objective of this study is to determine the relationship between placental parameters (weight and diameter) and the incidence as well as severity of Foetomaternal Haemorrhage (FMH). The secondary aim was to correlate FMH with maternal factors and neonatal anaemia. MATERIALS AND METHODSA total of 333 women who delivered in the hospital after 28 weeks of gestation were enrolled for the study. Maternal blood (2 mL) was collected in EDTA bottle after the delivery of the baby. Samples were sent to Blood Bank. FMH was quantified by KleihauerBetke's test. The foetomaternal haemorrhage is calculated as: Number of foetal cells per high power field/Number of maternal cells per high power field x 2400. 1 FMH > 2 mL was considered positive for FMH as per BSCH (British Committee for Standards in Haematology) guidelines. 2 Placental parameters like weight (after trimming cord at 5 mm from the insertion point and clearing membranes, clots) and diameter were measured. A cut-off of 500 gms for placental weight and 22 cm for placental diameter was taken. 3,4,5 Actual birth weight and neonatal Haemoglobin (Hb) was noted. BSCH = British Committee for Standards in Haematology. RESULTSOut of 333 subjects 48 (14.4%) were positive for FMH (Group 1) and 285 (85.6%) were negative for FMH (Group 2). The mean placental weight (508.54 ± 80.34 gm) and the mean placental diameter (19.92 ± 3.99 cm) were significantly more in patients having positive FMH when compared to those with negative FMH. (P value = 0.0005 for placental weight and p = 0.005 for placental diameter). When placental weight was ≥ 500 gm more subjects were significantly positive for FMH (25.6%) compared to when that was less than 500 gm (7%) (P value = 0.00). When the placental weight was between 600 and 699 gm, the odds of having FMH was 13.43 times more. When the placental diameter was ≥ 22 cm, the incidence of positive FMH was significantly more (33.9%) compared to when that was < 22 cm (10.2%) (P value = 0.00) and the odds of having positive FMH was 4.51 times. When the placental diameter was between 23 and 27 cm, the odds of having FMH was 5 times more. When the FMH was > 2 mL both mean placental weight (508.54 ± 80.34 gm) and diameter (19.92 ± 4.00 cm) were significantly higher when compared to lesser FMH. (P value 0.00 for both weight and diameter). Incidence of positive FMH was significantly more in maternal risk f...