Circulating microparticles: a risk factor for recurrent abortion in women at the University Teaching Hospital

Abstract

Spontaneous abortion in Zambia is defined as non-induced embryonic death or passage of products of conception before 28 weeks’ gestation. Placental insufficiency as a result of thrombi lodging in the uteroplacental bed is considered to be a cause of pregnancy loss. Circulating microparticles are minute sized particles associated with prothrombotic nature and have been found to be increased in the uteroplacental circulation in pregnancy, as such microparticles may be directly or indirectly associated with pregnancy loss. With abortion cases accounting for approximately 80% of cases presenting at the Obstetrics and Gynaecology emergency ward at The University Teaching Hospital, the objective of this study was to determine if circulating microparticles are associated with the risk of recurrent abortion. A total of 18 women with two or more recurrent abortions were enrolled in a case-control study and compared with 55 parous women as controls. After undergoing counselling performed by a trained midwife 24 hours after pregnancy loss or birth, a consent form was signed thereafter a questionnaire completed and 3mls of blood collected in a citrated container. Microparticles were measured in the isolated platelet poor plasma by flow cytometry using fluorescent annexin V-fluorescence isothiocyanate conjugate.Microparticle levels in cases was compared to controls using unpaired t-test and logistic regression used to determine the parameters of the questionnaire associated with abortion. Increased microparticle levels for both cases and controls was defined as more than 2 standard deviation above the mean of controls. The mean in this study was found to be 202/μl and was identified in 4 of the 18 women with recurrent abortions (22%), as compared to 2 of the 55 parous women (4%), t(20)=2.49, P=0.022, 95% CI 182.20-16.09. The increased levels of microparticles in the peripheral circulation of women with two/more unexplained pregnancy losses supports emerging evidence that microparticles have a role to play in abortion, however, more studies need to be carried out to confirm these findings. Key Words: Recurrent Abortion, Circulating Microparticles, Social Demographics.