[Birth weight prediction by B-type ultrasonic measurement of fetal transverse cerebellar diameter].

The fetal transverse cerebellar diameter (CD), biparietal diameter(BPD), abdominal circumference (AC) and femur length(FL) were measured by B-type ultrasonography on 222 normal pregnant women with one week before the expected date of confinement (EDC) and their correlations with birth weight of newborns were computerized. Single factorial analyses showed the best correlation was between CD and birth weight (R = 0.913 4) where as the R value for birth weight and AC, BPD, FL was 0.739 5, 0.612 5, 0.347 6 respectively. The F value of CD on stepwise regression analysis was the highest (F = 1001.95) while that of AC and BPD was 4.55, 4.36 respectively (P < 0.05). Then the regression equations of single double and triple factors were established. It was confirmed by clinical findings that the equation of log(BW) = 2,8844 + 0.01416 x CD was the most reliable one in predicting the birth weight. The error rate was less than 10% in 96% of the newborns.

Regulation of blood pressure in pregnancy: pressor system blockade and stimulation.

Contributions of the autonomic nervous system (ANS), renin-angiotensin system (RAS), and arginine vasopressin (AVP) to basal mean arterial pressure (MAP) were evaluated in near-term pregnant and virgin rats as follows. MAP and heart rate (HR) were measured before and after ganglionic, alpha-adrenoreceptor, RAS, and/or AVP blockade. In addition, pressor responses to angiotensin II (ANG II), norepinephrine, phenylephrine, or AVP were determined in ganglionic-blocked animals. In both groups decrements in MAP were greatest after ganglionic or alpha-blockade, intermediate after RAS blockade, and negligible after AVP-V1 antagonism ([d(CH2)5Tyr(Me)]AVP). Recovery of MAP was also similar in the two groups except after phentolamine when MAP and HR remained lower in gravid rats. Superimposition of RAS or AVP blockade during phentolamine infusion suggested that ANG II and AVP were less effective in supporting MAP during alpha-blockade in pregnancy. Pressor responses to ANG II and norepinephrine during ganglionic blockade were markedly blunted during pregnancy; however, those to phenylephrine and AVP were unchanged. We conclude that contributions of ANS, RAS, and AVP to basal MAP are similar in pregnant and virgin rats; neural mechanisms dominating in both groups. However, recovery during alpha-blockade is impaired during gestation, apparently due to blunted HR responses and decreased pressor contributions of ANG II and AVP. This may be explained, in part, by decreased vascular reactivity to ANG II, although a similar mechanism cannot be invoked for AVP.