Sumio Shin

The relationship between uterine artery Doppler velocimetry and umbilical venous adenosine levels in pregnancies complicated by preeclampsia

OBJECTIVE The aim of this study was to evaluate the relationship between uteroplacental circulatory insufficiency and the fetoplacental release of adenosine in pregnancies complicated by preeclampsia. STUDY DESIGN We performed uterine artery Doppler velocimetry and calculated the pulsatility index of the uterine artery, to detect uteroplacental circulatory insufficiency, immediately before cordocentesis in 39 pregnant women complicated by preeclampsia. Umbilical venous blood obtained by cordocentesis was then analyzed for blood gases, pH, and plasma adenosine levels. Increased plasma adenosine was taken to signal its increased release from the placenta and fetus relative to its rate of disappearance. RESULTS The mean umbilical venous plasma adenosine level in the abnormal pulsatility index group was 1.78 +/- 0.17 mumol/L (mean +/- SEM, n = 25), significantly higher than in the normal pulsatility index group 0.58 +/- 0.14 mumol/L (n = 14, p < 0.001). Furthermore, in the abnormal pulsatility index group the elevation of plasma adenosine levels in the umbilical vein was found even in normoxic fetuses. CONCLUSION Fetal plasma adenosine increases before uteroplacental circulatory insufficiency becomes severe enough to cause generalized fetal hypoxemia. We postulate that enhanced adenosine formation in the fetus, umbilical cord vessels, and particularly the placenta may, at least in part, contribute to control and maintenance of placental blood flow.

CLINICAL USEFULNESS OF MATERNAL BODY MASS INDEX IN TWIN PREGNANCIES

Objective: We examined whether maternal body mass index (BMI) during prepregnancy is useful for prediction of maternal preeclampsia in twin pregnancies. Methods: We studied 250 dichorionic twin pregnancies and 3196 singleton pregnancies. Maternal BMI was calculated during prepregnancy in both twin and singleton pregnancies. The incidence of maternal preeclampsia was compared among three groups, low-BMI [< −1.5 standard deviations (SD)], normal-BMI, and high-BMI (> +1.5 SD) groups, in both singleton and twin pregnancies. Results: In singleton pregnancies, the incidence of maternal preeclampsia in the high-BMI group was significantly higher than that in the normal-BMI group (p < 0.05). The relative risk by high BMI was 8.5 (95% confidence interval: 5.6–12.0). However, in twin pregnancies, no significant differences were observed in these values. Conclusions: Body mass index during prepregnancy was not useful for the prediction of preeclampsia in twin pregnancies. Mechanisms other than maternal weight may be associated with the beginning of preeclampsia in twin pregnancies.

Incidence of neonatal hypoglycemia in large-for-gestational-age infants of dichorionic twin pregnancies

Abstract The aim of this study was to estimate standards of large-for-gestational-age (LGA) infants of twin pregnancies based on the incidence of neonatal hypoglycemia. We examined 277 dichorionic twin infants (in 201 dichorionic twin pregnancies) who were delivered weighing ≥ 2500 g at 37–41 weeks of gestation. LGA in twin pregnancies was identified when the infant deviated > by 1.5SD from the mean gestational age of this study (LGA based on the twin pregnancy standard), or when the infant deviated by >1.5 SD of the intrauterine growth curve of Japanese (LGA based the singleton pregnancy standard). Using the twin pregnancy standard, the incidence of neonatal hypoglycemia in LGA twin infants was not measurably different from that in appropriate-for-gestational-age (AGA). However, using the singleton pregnancy standard, the incidence of neonatal hypoglycemia was significantly higher than that in AGA infants. In conclusion, LGA in twin pregnancies should be studied based on the singleton pregnancy standard to assess the incidence of neonatal hypoglycemia.

Fetal position associated with an increased risk of cesarean delivery in nulliparous twin gestations.

Keywords: cesarean section; delivery mode; fetal presentation; nulliparity; twin gestations