HUMAN CHORIONIC SOMATOMAMMOTROPIN (HCS) PLASMA LEVELS IN NORMAL AND PATHOLOGICAL PREGNANCIES AND THEIR CORRELATION WITH THE PLACENTAL FUNCTION

Abstract

ABSTRACT The results of a study of HCS plasma levels and behaviour in normal and pathological pregnancies may be summarized as follows: a) HCS plasma levels gradually increase during normal pregnancy, reaching the highest values at the 38–39th week after the last menstrual period; in the last few days of pregnancy and just before labour a slight decrease is observed; b) in threatened abortion the behaviour of HCS plasma levels in successive assays clearly divides the cases ending in spontaneous abortion (low or decreasing levels) from those favourably resolved; c) in molar pregnancies the very low HCS plasma levels support the diagnosis; d) in Rhesus-isoimmunization the HCS plasma levels are near normal in all the cases in which the foetus is only slightly affected. On the contrary, very high levels were found in cases of foeto-placental hydrops and the rapid increase in HCS plasma levels in these cases seems to correlate with the appearance of hydropic conditions; e) in diabetic pregnancies, the HCS plasma levels are normal or slightly below normal; decreasing HCS values in subsequent assays preceded the intra-uterine foetal death (IUFD) in one case; two cases of juvenile diabetes treated with less than the required doses of insulin showed very high HCS values; f) in preeclamptic pregnancies the HCS levels are lower than normal and show no further increase after the 32–33rd week; several cases followed up for some weeks support this observation, and cases ending in IUFD or premature labour showed very low HCS levels; g) similarly, low HCS levels which failed to increase in subsequent assays are found in all the cases of foeto-placental dystrophy and multiple placental infarct; h) the cases of IUFD in uncomplicated pregnancies examined during the first 24 hours after the IUFD demonstrate normal or raised HCS levels in three cases where IUFD occurred before the 27th week, and below normal values in 7 out of 9 cases where IUFD occurred afterwards; i) higher than normal levels are demonstrated in twin pregnancies and pregnancies with large babies; j) a significant correlation between the foetal weight and the HCS levels is demonstrated if the plasma samples are collected at least five days before delivery; k) in prolonged pregnancy the observation of low HCS levels clearly indicates the presence of foetal post-maturity or chronic foetal distress; in fact, in uncomplicated prolonged pregnancies the HCS plasma levels are similar to those found in normal pregnancy at term. All these data indicate the value of plasma HCS radioimmunoassay in an evaluation of the placental function and sustain the importance of its application during the whole pregnancy, and in the presence of any pathological condition of gestation.