Role of Placenta Parameters in Predicting Significant Feto-Maternal Haemorrhage

Purpose: Feto-maternal haemorrhage (FMH) is a complication of pregnancy and large FMH may lead to life-threatening anaemia in the fetus or newborn. In addition, exposure of Rhesus (Rh) D negative women to small amounts of fetal Rh D positive red cells during pregnancy or delivery may result in sensitization with its attendant problems of isoimmunisation. In most cases, the cause of FMH IS unknown. Through this study, we sought to determine if placental weight & diameter have any direct relationship with incidence and severity of FMH.Methods: This was a prospective study of parturients for presence of fetal red cells in the maternal blood circulation. The prepared slide was processed as in the acid elution test described by Kleihauer-Betke. The FMH was calculated using Mollison formula. Baseline data included maternal biodata, blood group, Rh D factor, placenta weight and diameter. Data generated were analysed with Frequency tables, cross-tabulations and Odd ratio and confidence intervals as appropriate.Results: Three hundred parturients were studied. However, only two hundred and ninety-five parturients were analysed, with five excluded due to lysed blood samples. A total of 52 parturients (17.63%) had demonstrable FMH, of which 8 (2.71%) were large FMH (>15 ml foetal cells). Both the placenta weight (P g, in contrast to 4.17% (4/96) in the group with weight of placenta below or equal to 500 g. All the 8 parturients with large FMH had placenta weights greater than 500 g. Placenta diameters were greater than 22 cm in 41/197 (20.81%) who had demonstrable FMH, compared with 11/98 (11.23%) whose diameter was less than 22 cm. Conclusion:Both the placenta weight and diameter are significant predictors of FMH in parturients. However, placenta diameter appears to be a minor predictor. These are factors that can be assessed antenatally by ultrasonography and in conjunction with other known obstetric factors, may possibly be considered in risk-based scoring system for predicting feto-maternal haemorrhage.

Immune system modifications and feto-maternal immune tolerance

Objective This review aimed at understanding pregnancy-induced changes in the maternal immune response and mechanisms for the establishment of feto-maternal tolerance.Data sources Articles cited in this review were obtained from PubMed in English from 2000 to 2014,and the search string included keywords such as feto-maternal tolerance,dendritic cells,macrophage,T regulatory cells,natural killer cells,cytokines and hormone.Study selection Articles regarding altered maternal immune response,including the proliferation and differentiation of the altered cells,and the production of cytokines and regulation of hormones in the feto-maternal interface were retrieved,reviewed and analyzed.Results The changes in immune cells and cytokines in the local uterine microenvironment and peripheral blood are correlated with the establishment of feto-maternal tolerance.The endocrine system regulates the maternal immune system,promoting modifications during pregnancy.In these regulatory networks,every factor is indispensible for others.Conclusions The integration and balance of these immune factors during pregnancy give rise to an environment that enables the fetus to escape rejection by the maternal immune system.This progress is complicated,and needs more comprehensive exploration and explanation.