Pre-eclampsia/eclampsia in twin pregnancies.

Abstract

Summary. A study of 1045 twin gestations with regard to known or likely zygosity and the incidence of pre-eclampsia/eclampsia failed to reveal differences between known dizygous twins and like-sex 'presumed' and 'estimated' monozygous twins except in the 'estimated' data for multigravidae. There was a threefold increase in the incidence for twins as opposed to singleton pregnancies. These results are discussed in relation to increased conceptus-mother antigenic differences. It is suggested that the risk of gestosis in twin pregnancy involves more than a summation of that operating in two singleton pregnancies.It has been suggested that genetic incompatibility between mother and fetus may be a factor in the aetiology of pre-eclampsia (Penrose, 1946;Kalmus, 1946;Platt, Stewart, and Emery, 1958). Epidemiological evidence has been provided by Stevenson et al (1971) in a study of consanguineous marriages in the Middle East. They also recorded twin data which pointed to a higher incidence of toxaemia in unlike-sex as opposed to like-sex twin pregnancies. As all unlike-sex twins are dizygous (DZ) and a large proportion of like-sex twins are monozygous (MZ), antigenic differences between mother and conceptus would be more likely to be expressed in unlike-sex twin pregnancies. Stevenson et al considered that the higher incidence with unlike-sex twins could be attributed to this. They extrapolated their data on the basis of Weinberg's hypothesis involving the assumption that for every pair of unlike-sex DZ twins there is one like-sex DZ pair. The estimated differences in the incidence of pre-eclampsia based on this were significant at P values of <0.05 to 0.001, the syndrome being commoner in the presumed DZ cases. They regarded these findings as 'suggestive'.This report concerns a review of twin deliveries in one hospital with regard to zygosity and the incidence of late pregnancy hypertension. MethodThe records of twin gestations from 1953 to 1973 in-clusive at Leeds Maternity Hospital were studied.

Hypertensive disorders in twin pregnancy

“…The median gestational age at termination of pregnancy for this indication was 37 (32-40) weeks in twin pregnancies and 34 (28-36) weeks in singletons (P < 0.05). Birthweight ratios in twin pregnancies complicated by PIH (median, 0.86; range, 0.70-1.02) were orders in twin and singleton pregnancies are in general agreement with those obtained in other large series of twin pregnancies and singleton controls [2,3,8]. However, the definition of hypertensive disease in pregnancy varies greatly in those reports, in particular with regard to the presence or absence of proteinuria, an important determinant of the severity of the disease and of pregnancy outcome [15].…”

“…Part of the differences may be explained by geographical variation in the prevalence of hypertensive disorders, but the majority of reports in the literature cannot be used for international comparison. The elevated incidence of preeclampsia in twin pregnancy in hospital-based studies [3,8] could be due, at least in part, to selection bias, because patients with pre-eclampsia may be more easily referred to a tertiary care center than women with PIH alone. For that reason we included in our study only women who were under our antenatal care before 24 weeks' gestation.…”

“…Incidences of 20-30% are reported, 3-5 times higher than in singleton pregnancies [1][2][3]. Unfortunately, the older studies in particular lack adequate control groups and the criteria used to define hypertensive disease vary markedly [3,[4][5][6][7][8]. In some cases no distinction is made between pregnancy associated with hypertension already existing before pregnancy and pregnancy-induced hypertensive disorders, with or without proteinuria [4][5][6][7][8].…”

“…Unfortunately, the older studies in particular lack adequate control groups and the criteria used to define hypertensive disease vary markedly [3,[4][5][6][7][8]. In some cases no distinction is made between pregnancy associated with hypertension already existing before pregnancy and pregnancy-induced hypertensive disorders, with or without proteinuria [4][5][6][7][8]. In addition, many reports do not distinguish between proteinuric pre-eclampsia, with its increased maternal and fetal risks, and non-proteinuric pregnancy-induced hypertension, the main risk of which is the development of pre-eclampsia [9].…”

Routine uterine artery Doppler screening in twin pregnancies?

“…Therefore, with the higher prevalence of such complications in multiple pregnancies, the development of a screening test to identify those at highest risk would potentially be of great value. However, although the prevalences of complications such as PET and IUGR are similar to those previously reported in twin pregnancies 9,11,15,16 , the current studies demonstrate that the different physiological effects of multiple pregnancy on the maternoplacental circulation affect the performance of uterine artery Doppler velocimetry as a screening test. Hence, the mean uterine artery resistance, measured as pulsatility index (PI) or resistance index (RI), is lower in twin compared with singleton pregnancies 1,2 , presumably reflecting, at least in part, a larger placental implantation site area.…”