Second trimester levels of maternal serum inhibin A in pregnancies affected by fetal neural tube defects

Inhibin A is effective as a second trimester maternal serum marker for Down syndrome screening. In the present study, inhibin A levels were measured in second trimester maternal serum samples from 28 pregnancies affected with open neural tube defects; 12 associated with open spina bifida and 16 associated with anencephaly. Each measurement was expressed as a multiple of the median (MoM) for control singleton pregnancies (n=1464) of the same completed week of gestation. Inhibin A levels were not significantly altered in cases of open neural tube defects; the median value was 0.96 MoM in cases of open spina bifida and 1.19 MoM in cases of anencephaly. Therefore, second trimester maternal serum inhibin A levels will not have an impact on prenatal detection of open neural tube defects.

Combination of elevated maternal serum alpha-fetoprotein (MSAFP) and low estriol is highly predictive of anencephaly

Increased levels of second trimester maternal serum alpha-fetoprotein (MSAFP) have long been established as a marker for neural tube defects (NTDs). In addition, decreased levels of maternal estriol in the third trimester have been reported in pregnancies with anencephalic fetuses. The purpose of this study was to evaluate whether early second trimester unconjugated serum estriol (uE3) is an independent predictor of NTDs. The study included 57,031 patients who underwent maternal serum screening with MSAFP at 14-22 weeks gestation. Of these, 23,415 also had uE3 measurements. There were 63 cases of NTD, an overall incidence of 1.1 per 1,000. Elevated MSAFP (> or =2.5 MOM) was detected in 1,346 patients, 48 of which had NTDs. Decreased uE3 (< or =0.5) was detected in 1,437 patients, 17 of which had NTDs. The incidence of NTDs was significantly higher in patients with low uE3, compared to patients with normal/high uE3 (1.15% vs. 0.09%, P < 001). Finally, 51 patients had both increased MSAFP and decreased uE3; 16 of these had NTDs, 14 of which were anencephalics. In conclusion, both elevated MSAFP and low maternal serum estriol are predictive of NTD but have a low sensitivity. The combination of abnormally elevated MSAFP and low estriol is highly predictive of NTD in particular anencephaly.

Maternal serum alpha-fetoprotein in fetal neural tube and abdominal wall defects at 10 to 14 weeks of gestation

Maternal serum alpha-fetoprotein concentration was determined in nine pregnancies with fetal anencephaly, seven with exomphalos containing liver, two with spina bifida and 100 normal controls at 10 to 14 weeks of gestation. The median alpha-fetoprotein in the group with fetal anencephaly and exomphalos was significantly higher than in normal fetuses but the sensitivity of this test is likely to be only about 30% for a false positive rate of 5%.

Maternal and fetal serum and red blood cell folate and vitamin B12 concentrations in pregnancies affected by neural tube defects

In the present study maternal and fetal serum and red cell folate and vitamin B12 concentrations were determined in NTD affected and in control pregnancies. Fetal serum folate (p < 0.001) and red cell folate (p < 0.001) concentrations were significantly higher than maternal levels in the cases as well as in the controls. Maternal and fetal vitamin B12 concentrations did not differ significantly in both groups. There were also no significant differences in maternal and fetal vitamin concentrations in the peripheral blood between cases and controls. However, when a subgroup analysis was performed according to the type of NTD we found significant differences in fetal vitamin B12 status between anencephaly and spina bifida cases as well as between anencephaly cases and the controls.

Circulating levels of growth hormone, insulin-like growth factor-I and prolactin in normal, growth retarded and anencephalic human fetuses

We measured growth hormone (GH), insulin-like growth factor-I (IGF-I), and both total and glycosylated prolactin (PRL) levels in 131 blood samples obtained by cordocentesis in normal and abnormal fetuses from 19 to 40 weeks of gestation. In normal fetuses, IGF-I and PRL levels showed a positive correlation and GH a negative correlation with gestational age. A negative relation between GH and IGF-I levels was observed, while PRL did not show any correlation with both GH and IGF-I concentrations. IGF-I increased from 5.6 +/- 3 (at 19-22 weeks) to 10.7 +/- 5 nmol/l at term; GH decreased from 31 +/- 10 to 7.7 +/- 4 micrograms/l and PRL increased from 16 +/- 18 to 139 +/- 76 micrograms/l. Glycosylated PRL accounted for about 15% of total PRL, a value similar to that found in normal adults. In 27 fetuses of 27-37 weeks with intra-uterine growth retardation, GH and PRL levels were higher and IGF-I levels lower than in normal fetuses matched for week of gestation. In 8 anencephalic fetuses of 19-26 weeks of gestation, both GH and IGF-I levels were lower, and PRL levels were higher than in matched controls. Altogether these data support the views that a) both GH and PRL secretion are under the hypothalamic control during fetal development, b) the serum GH decrease from midgestation to the end of pregnancy is mediated by the negative feed-back mechanism of increasing IGF-I levels and c) IGF-I production is mainly regulated by fuel supply and only partially by GH.

[Noninvasive serum test for prenatal detection of Down syndrome, other chromosome abnormalities and open neural tube defects--a prospective study]

Between September 1st 1990 and Juli 31st 1993, 5071 pregnant women were screened prospectively by the "triple-test", including maternal serum alpha-fetoprotein, human chorionic gonadotropin and unconjugated oestriol in order to detect chromosomal anomalies and open neural tube defects. The serum samples were collected in collaboration with the obstetricians of the region of West-Mecklenburg and North-West-Brandenburg. Laboratory testing using radioimmunoassays was performed between weeks 15 and 20 of gestation, all serum specimens being investigated in only one institution. The original alpha-software from Wald et al. was the basis for calculating the statistical risk for Down's syndrome. Pregnant women with a high risk for Down's syndrome (cutoff > or = 1:250) were taken care of in a special outpatient clinic including procedures like amniocentesis and fetal blood sampling. Amongst 5071 pregnant women, 21 fetal anomalies were seen. Five cases of Down's syndrome, three of trisomy 18, one trisomy 13, two cases of triploidy and four cases of open neural tube defects, one 46 xy/45 x mosaic karyotype and one case of gastroschisis could be diagnosed correctly. One case of trisomy 21, one case of trisomy 18 and two open neural tube defects showed false negative results. Using the cutoff of 1:250 for prenatal detection of Down's syndrome and performing ultrasound routinely to determine gestational age, the sensitivity of the "triple-test" was 83.33% having a specificity of 92.68%. The predictive value of a positive test for prenatal diagnosis of Down's syndrome was 1.33%.(ABSTRACT TRUNCATED AT 250 WORDS)

[2 cases of anencephaly in one family]

Two births of anencephalic fetuses occurred in the second and the fourth pregnancies in a family. The children born after the 1st and 3rd pregnancies were normal. Anencephaly was not associated with spina bifida, and both fetuses were female. The study failed to demonstrate the cause of the abnormality.

Quick measurement of serum unconjugated estrogens, and its clinical application to abnormal pregnancies and ovarian follicle maturation

Using an automated HPLC system reported recently by us (J Clin Lab Anal 4:410-413, 1990), serum unconjugated estriol and estradiol (u-E3 and u-E2) can be measured within 22 min. The clinical value of this method was evaluated in this study with abnormal pregnancies, twin pregnancies, and pregnancies associated with fetal anencephaly or complicated by gestational toxicosis or diabetes mellitus. A significant correlation was demonstrated between an abrupt decrease in serum u-E3 level and an abnormal pattern on fetal heart rate monitor. Since urinary E3 was not sensitive enough to detect any depressed fetal condition, serum u-E3 is better biochemical parameter for assessment of fetal well-being. In addition, u-E2 was measured in the sera of nonpregnant women with separation chromatography as a pretreatment in order to obtain higher sensitivity of the system. This modified HPLC system enabled us to determine the serum u-E2 in about 60 min with the minimal detectable value of 80 pg/ml; the coefficient of correlation with RIA was 0.822. As a result, this quick measurement of u-E3 and u-E2 by our HPLC system revealed to be useful not only for evaluating fetoplacental function but also for monitoring ovarian follicle maturation.

Fetal hyperinsulinism in anencephaly

Insulin was measured in the blood collected in utero from three midtrimester anencephalic fetuses. The hyperinsulinism found could be due to an underutilization of glucose in the absence of most of the brain and could be responsible for the relatively normal growth in anencephaly despite the absence of the hypothalamohypophysial axis.

The effects of dexamethasone and anencephaly on newborn serum levels of apolipoprotein A-1

Since the control of production and clearance of plasma lipoproteins in utero is largely unknown, we sought to evaluate the effects of glucocorticosteroid (dexamethasone) treatment of developing fetuses and of chronic intrauterine hypercholesterolemia, due to fetal anencephaly, on newborn serum levels of apolipoprotein A-1 (Apo A-1), the major apoprotein of high density lipoproteins (HDL). Among preterm newborn infants (26-32 weeks gestation), the total, HDL, and low density lipoprotein cholesterol levels in umbilical cord serum of 11 newborns exposed to 4 doses of dexamethasone (5 mg each) within 1 week of delivery [mean, 3.05 +/- 1.01 (+/- SD), 0.83 +/- 0.18, and 1.84 +/- 0.69 mmol/L, respectively] and of 3 anencephalic newborns (2.84 +/- 0.57, 0.83 +/- 0.36, and 1.89 +/- 0.54 mmol/L) were increased to a similar extent over those in 17 normal newborns (1.76 +/- 0.16, 0.62 +/- 0.16, and 1.14 +/- 0.13 mmol/L). On the other hand, umbilical cord serum Apo A-1 levels were markedly increased only in the dexamethasone-treated preterm newborns (1.35 +/- 0.55 g/L; anencephalic, 0.78 +/- 0.15 g/L; normal, 0.68 +/- 0.06 g/L). Also, whereas serum total, HDL, and low density lipoprotein cholesterol levels in 5 term anencephalic newborns (3.85 +/- 1.37, 1.06 +/- 0.08, and 2.64 +/- 0.91 mmol/L) were substantially higher than those in 41 normal term newborns (1.42 +/- 0.28, 0.57 +/- 0.12, and 0.74 +/- 0.05 mmol/L), serum Apo A-1 levels were similar at term in anencephalic (1.01 +/- 0.30 g/L) and normal newborns (0.99 +/- 0.08 g/L). Normal Apo A-1 and lipoprotein cholesterol levels were found in an additional newborn who was delivered 30 days after exposure to dexamethasone. We conclude that intrauterine glucocorticosteroid treatment leads to transiently increased serum Apo A-1 levels in the newborn. This increase, however, is not likely to be secondary consequence of the hypercholesterolemia that also occurs in such newborns, since hypercholesterolemia of a similar extent in anencephalic newborns, who have atrophic adrenals, was not associated with marked changes in serum Apo A-1 levels.

Mineralocorticosteroids and pregnancy: regulation of extra-adrenal deoxycorticosterone production by estrogen

During pregnancy, deoxycorticosterone (DOC) in maternal plasma is produced principally by 21-hydroxylation of circulating progesterone in a number of extra-adrenal tissues. Estrogen acts, directly or indirectly, to increase the transfer constant of conversion of progesterone to DOC. In this study, we evaluated the regulation of DOC production during pregnancy by considering the plasma levels of progesterone, the kinetics of extra-adrenal steroid 21-hydroxylase, and the stimulation of the conversion of progesterone to DOC by estrogen.

Lecithin-sphingomyelin ratios in amniotic fluid of pregnancies with an anencephalic fetus

As many investigators have shown that surfactant production in the developing human lung is subject to multihormonal regulation, the present authors determined the lecithin-sphingomyelin (L/S) ratio in amniotic fluid of pregnancies with an anencephalic fetus, in which there was known to be aberrant production of fetal pituitary, adrenal, and consequently, placental hormones. The L/S ratio in amniotic fluid from seven of eight pregnancies with an anencephalic fetus was substantially lower than that in amniotic fluids of pregnancies with a normal fetus at the same stage of gestation. The L/S ratio in amniotic fluid of an anencephalic fetus of a twin pregnancy (monochorionic diamniotic) at 34 weeks' gestation was low; the L/S ratio of the amniotic fluid of the normal fetus was high. These data are supportive of the view that fetal lung maturation is dependent, in part, upon normal function of the fetal pituitary and adrenal.

Insulin-like growth factors (IGF) 1 and 2 in human foetal plasma and relationship to gestational age and foetal size during midpregnancy

IGF-1 and IGF-2 were measured by specific radioimmunoassay after acid-ethanol extraction of plasma obtained by foetoscopy from 20 normal foetuses aged 15-23 weeks. IGF-1 and IGF-2 levels were 36 +/- 11 and 162 +/- 55 ng/ml, respectively. In comparison, levels in cord blood were 84 +/- 58 and 264 +/- 176 ng/ml, respectively, and in adult plasma were 410 +/- 106 and 818 +/- 272 ng/ml. Both IGF-1 and IGF-2 were in the normal foetal range in a further three foetuses with anencephaly and two foetuses with spina bifida. No sex difference was observed. IGF-1 was positively correlated with foetal body weight (P less than 0.001), placenta weight (P less than 0.02) and with body length measured crown-rump (P less than 0.01) or crown-heel (P less than 0.02). No correlation between IGF-2 and body weight, length, placenta weight or gestational age was found. Both IGF-1 and IGF-2 are present in the human foetal circulation earlier in gestation than has previously been demonstrated, the levels being low throughout this period of gestation in comparison with adult plasma.

Umbilical cord plasma concentrations of deoxycorticosterone sulfate in anencephalic fetuses

In the present investigation, we determined the levels of deoxycorticosterone sulfate in mixed umbilical cord plasma of anencephalic abortuses and newborn infants. The anencephalic fetus is an interesting model with respect to the production of deoxycorticosterone and deoxycorticosterone sulfate on several accounts. There is profound adrenal atrophy in most such fesuses, and, in consequence, there also is relatively profound hypoestrogenism. This is an important consideration in the formation of deoxycorticosterone and deoxycorticosterone sulfate since it is known that estrogen acts to stimulate extra-adrenal steroid 21-hydroxylase and 21-hydroxysteroid sulfotransferase activities. The plasma levels of deoxycorticosterone sulfate in 22 anencephalic abortuses and newborn infants delivered between 21.5 and 45.5 weeks of gestation ranged from 1.8 to 30.3 ng/ml. The concentrations of deoxycorticosterone sulfate in umbilical cord plasma of anencephalic fetuses and newborn infants were not related to gestational age or method of delivery and, at term, were less than 13% of those in umbilical cord plasma of normal newborn infants. These data can be interpreted to indicate (1) that deoxycorticosterone sulfate normally is secreted directly by the fetal adrenal or (2) that placental estrogen normally derived largely from fetal adrenal dehydroisoandrosterone sulfate is essential for the maintenance of plasma deoxycorticosterone sulfate levels in the fetus by stimulating extra-adrenal deoxycorticosterone sulfate production from plasma progesterone, or both.

Serum copper concentration significantly less in abnormal pregnancies

We estimated copper concentration in maternal serum during 244 normal and 15 abnormal pregnancies. Values were lower in the abnormal pregnancies than in the normal ones, and did not vary with gestational age between 15 to 18 weeks in normal pregnancies.

The human fetal prolactin and estradiol levels, and their correlationship

Serum prolactin and estradiol-17 beta levels were determined in umbilical cord sera obtained from 33 preterm, 118 full-term and 11 anencephalic infants and in peripheral sera obtained from 5 neonates. Prolactin levels increased from mid-gestation toward term, and markedly decreased after birth. Those in anencephalic infants (253 +/- 86 ng/ml, mean +/- S.D.) were lower than in full-term infants (324 +/- 119 ng/ml), but the difference was not statistically significant. We also performed thyroid-releasing-hormone (TRH) (50-200 micrograms) test on 5 anencephalic infants, but significant changes of serum prolactin levels were not found. Estradiol-17 beta levels in anencephalic infants were significantly lower than those in full-term infants. There was a significant positive correlation between cord prolactin and estradiol-17 beta levels in full-term infants. These results suggest one of the control factors for human fetal pituitary prolactin secretion is estrogen, and hypothalamic factors are not so important.

[The dynamics of corticosteroids levels in maternal and fetal plasma]

In order to elucidate the clinical implications of cortisol levels in pregnancy, maternal and fetal serum levels of cortisol during pregnancy were determined. The maternal serum level of cortisol gradually increased with advancing gestational age, and it reached a 3 to 4 times higher level in the late stage of pregnancy than that in non-pregnant state. The maternal serum level of cortisol during delivery increased with the length of the period of labor, and immediately after the delivery it reached the peak value of 60-80 micrograms/dl. According to the mode of delivery, the cortisol level increased with the accumulation of stress on the maternal side. The value was highest in the case of vacuum extraction and lowest in elective cesarean section. The cortisol level in umbilical arterial blood in normal delivery was not significantly elevated in comparison with that in vacuum extraction, oxytocin induced delivery and elective cesarean section. The cortisol level in umbilical blood of anencephaly did not differ from that of normal neonate, indicating that cortisol in umbilical blood may originate mainly on the maternal side. In the postpartum period, the serum cortisol concentration declined to the level observed in the late stage of pregnancy after 2 days, and further decreased to the level in the non-pregnant state after 6 days. The present studies suggest that the increase in the serum concentration of cortisol at delivery is a result of maternal stresses in labor, and that direct involvement of cortisol in the controlling mechanism of puerperium is unlikely. The increased function of the adrenal cortex in the late stage of pregnancy and at delivery may stimulate fetal pulmonary maturity and provide maternal and fetal adaptability to stresses in intrapartum bleeding and shock during labor. It is essential to understand pituitary-adrenal cortex functions in prenatal and fetal care in pregnancy.

Hyperzincemia in anencephaly and spina bifida: a clue to the pathogenesis of neural tube defects?

Zinc is essential for normal embryogenesis and may have particular importance for closure of the human neural tube. Compared to 258 controls, we found increased zinc content in umbilical cord serum in eight of nine newborn anencephalics (p less than 0.02) and three infants with spina bifida (p less than 0.001). Increased zinc levels were bound to serum albumin or alpha-2-macroglobulin (alpha 2M) in infants with neural tube defects (NTD). In NTD-mothers, total serum zinc was similar to controls, but there was a shift in the distribution of zinc from alpha 2M to albumin. Fetal hyperzincemia and elevated maternal albumin-bound zinc suggest that the NTD-fetus receives but does not use zinc normally.

Plasma 11-deoxycortisol in normal and abnormal human pregnancy

11-Deoxycortisol was assayed in maternal and cord plasma. The concentrations in maternal plasma increased as pregnancy progressed and reached a peak at 39 weeks. The levels decreased very rapidly in the postpartum period. In cases of intrauterine fetal death and anencephalic fetuses, the values were apparently lower than normal. In women who had undergone bilateral adrenalectomy, the maternal plasma levels were almost normal. The maternal levels were high in cases of twin pregnancies. Therefore, it is assumed that the fetus or the fetoplacental unit is the source of the increased 11-deoxycortisol in maternal plasma during late pregnancy.

Extra-adrenal deoxycorticosterone production in hypoestrogenic pregnancies: Serum concentrations of progesterone and deoxycorticosterone in anencephalic fetuses and in women pregnant with an anencephalic fetus

In a continuing effort to define the origin of and the regulation of the production of deoxycorticosterone, we measured deoxycorticosterone and progesterone in the umbilical cord plasma of 16 anencephalic fetuses and newborn infants (21 to 45 weeks' gestation) and deoxycorticosterone, progesterone, 17 beta-estradiol, and estriol in the plasma of 18 women pregnant (16 to 45 weeks) with an anencephalic fetus. Whereas umbilical cord plasma levels of progesterone in the anencephalic fetuses were similar to those of normal abortuses and newborn infants, those of deoxycorticosterone (1.3 +/- 0.21 ng/ml, mean +/- SE) were significantly lower (P less than 0.001) than those in normal abortuses and newborn infants delivered between 31 and 42 weeks' gestation (3.94 +/- 0.26 ng/ml). We found that plasma levels of deoxycorticosterone were significantly correlated (P less than 0.001) to those of progesterone in women pregnant with an anencephalic fetus, as well as in women pregnant with a normal fetus. Plasma levels of deoxycorticosterone (range = 0.14 to 0.92 ng/ml) in women pregnant with an anencephalic fetus were significantly lower than those in women pregnant with a normal fetus; plasma levels of progesterone were similar in both groups. The plasma levels of 17 beta-estradiol and of estriol were extremely low in women pregnant with an anencephalic fetus compared with those in women with a normal fetus and did not vary as a function of gestational age. In one subject who was pregnant with an anencephalic fetus, we found that estrogen treatment (100 mg of diethylstilbestrol/day) for 6 days caused a progressive increase in the serum levels of deoxycorticosterone and in the ratio of the concentration of concentration of deoxycorticosterone to that of progesterone in serum. Both the serum levels of deoxycorticosterone and the ratio of the concentration of deoxycorticosterone and in the ratio of the concentration of deoxycorticosterone to that of progesterone declined after cessation of estrogen treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Metabolic clearance rate of plasma deoxycorticosterone sulfate in men and women

In the present investigation, we determined the metabolic clearance rate of plasma deoxycorticosterone sulfate in adult men and nonpregnant women and in one women pregnant at 42 weeks gestation with an anencephalic fetus. The values obtained varied from 618 to 10701/24 h. The metabolic clearance rate of deoxycorticosterone sulfate, expressed as a function of body surface area, was 495 +/- 31.71/24 h/m2 (mean +/- SEM) and was not significantly different among men and nonpregnant women. In a woman pregnant with an anencephalic fetus at 42 weeks gestation, the metabolic clearance rate of deoxycorticosterone sulfate was 6441/24 h/m2. We suggest that the high clearance rate of this steroid 21-sulfate, compared with those of other steroid sulfates, is due to rapid excretion of deoxycorticosterone sulfate into bile and irreversible metabolism in intestine by bacterial enzymes.

Hypercholesterolemia due to elevated low density lipoprotein-cholesterol in newborns with anencephaly and adrenal atrophy

In the present investigation, we evaluated the relationship between plasma lipoprotein-cholesterol and adrenal steroid production in abortuses and newborns in whom the adrenal was expected to be atrophic, i.e. in anencephalics. We found that umbilical cord plasma levels of dehydroepiandrosterone sulfate (DS) in 23 anencephalics delivered between 13.5 and 45.5 weeks of gestation (mean +/- SE, 176 +/- 37 ng/ml) were significantly lower than those in normal newborns of similar gestational ages; the umbilical cord plasma concentrations of cortisol in many anencephalics, however, were within normal limits. The levels of total cholesterol (134 +/- 10 mg/dl) and low density lipoprotein (LDL)-cholesterol (94 +/- 8 mg/dl) were substantially higher (up to 4-fold) in umbilical cord plasma of anencephalics than in umbilical cord plasma of normal newborns. The mean level of high density lipoprotein-cholesterol in umbilical cord plasma of anencephalic abortuses and newborns (38 +/- 4 mg/dl) was approximately 50% higher than that in normal newborns. The lowest plasma cholesterol level (56 mg/dl) and a concentration of DS (480 ng/ml) that was among the highest seen in the group of anencephalics were found in an anencephalic newborn in whom adrenals were of near-normal weight. Plasma cholesterol levels were inversely correlated to adrenal weights and plasma DS levels, and plasma DS levels were correlated to adrenal weight. Whereas the estimated plasma pool of DS in normal newborns increased to over 300 micrograms during the latter part of gestation, that of anencephalic newborns was much lower (less than 1 to 26 micrograms) and did not appear to increase as a function of gestational age. Conversely, the estimated plasma pool of cholesterol in normal newborns appeared to decline slightly during the last 10 weeks of gestation (80 mg at term), whereas that of anencephalic newborns expanded greatly near term; levels (approximately 200 mg) were attained that were about 3 times those in normal newborns. We conclude that the hypercholesterolemia in anencephalic newborns, due primarily to extremely elevated plasma levels of LDL-cholesterol, is a result of decreased uptake and utilization of plasma LDL-cholesterol for steroid biosynthesis by the adrenals. Since hypercholesterolemia is apparently early in gestation in anencephalic abortuses, we speculate that in normally developing fetuses, plasma LDL-cholesterol is used as substrate for adrenal steroidogenesis early in gestation as well as near term when the rates of growth and steroid production by the adrenals accelerate markedly.

The efficacy of a serum screening service for neural-tube defects: the South Wales experience

Serum-alpha-fetoprotein (AFP) levels were measured in more than 15 000 pregnant women in an investigation designed to examine the operational issues entailed in a large-scale population screening programme for antenatal detection of neural-tube defects. The proportion of open neural-tube defects (ONTD) terminated as a result of serum screening was 56.1% (66.6% for anencephaly and 40.7% for open spina bifida). The principle causes of poor efficacy were: failure of pregnant women to undergo screening (18.2% of ONTD were not screened); failure of the screening test to detect ONTD (20.4% of those screened were below the 90th centile); decisions against termination of detected ONTD (14% of ONTD detected by serum AFP were not terminated). Given present practices and knowledge it is doubtful whether overall efficacy levels above 65% for open spina bifida can be achieved under normal service conditions. The establishment of a regional or national screening programme on grounds of clinical efficacy alone may be premature. The decision would seem to hinge principally around a careful consideration of the economic issues.

Zinc levels of serum, plasma, erythrocytes and hair in Turkish women with anencephalic babies

The present study revealed a significantly low zinc concentration, measured by atomic absorption spectrophotometry, in serum, plasma and erythrocytes of mothers with anencephalic babies as compared to two control groups of women. We feel that Turkey should be added to the list of geographic regions where zinc deficiency has been found together with a high rate of CNS malformations.

Feto-maternal plasma oxytocin levels in normal and anencephalic pregnancies

In 4 women with anencephalic fetuses, the oxytocin level was measured in the maternal plasma in the second stage of labor and in the umbilical artery (UA) and umbilical vein (UV) by radioimmunoassay (RIA). In these cases, the mean maternal OT level was 13.4 +/- 8.0 microU/ml (mean +/- S.E.), which was not significantly different from the OT levels in cases of normal spontaneous birth and elective cesarean section. The UA and UV plasma OT levels in these cases were below the detectable level (less than 2 microU/ml), whereas in normal spontaneous births, they were 18.2 +/- 4.9 microU/ml and 12.2 +/- 2.3 microU/ml, respectively. The OT level in the UA was higher than that in the UV. There was no difference between the mean OT levels in patients with, versus those without contractions, but the plasma OT levels in the second stage of labor were higher than those in the first stage. In normal pregnancies the plasma OT concentration increased during parturition. These results suggest that placental transfer of maternal plasma OT to the fetal circulation is limited, and that in cases of anencephalic fetuses, maternal labor does not necessarily require fetal OT as a trigger or for its maintenance.

[Secretion and Sex differences in cord serum growth hormone levels of the human fetus (author's transl)]

Cord venous growth hormone (GH) and somatostatin levels were measured by radioimmunoassay in 86 infants and 11 anencephalic infants. 1) Cord GH levels were 69.2 +/- 20.2 ng/ml (N = 6, gestational weeks (GW) : 21-30W, mean +/- S.D.), 31.5 +/- 24.3 ng/ml (N = 11, GW : 31-36W), and 17.6 +/- 8.9 ng/ml (N = 71, GW: 37-41). In anencephalic infants, cord GH levels were significantly lower (2.3 +/- 1.4 ng/ml) than those in preterm and fullterm infants. 2) In fullterm infants, cord GH levels of small infants (19.2 +/- 9.2 ng/ml, N = 33, birth weight less than 3,250g) were significantly higher than that of large infants (15.1 +/- 8.1 ng/ml, N = 38, birth weight greater than of equal too 3,250g). On the other hands, cord somatostatin levels were relatively lower in small infants than in large infants. 3) There was a significant difference between male cord GH levels (20.6 +/- 8.9 ng/ml, N = 35) and female cord GH levels (14.6 +/- 8.0 ng/ml, N = 36). These results suggest that fetal GH secretion is suppressed by GH inhibiting factor (somatotropin release inhibiting factor) from mid gestation toward term and there is a sex difference of fetal GH secretion in fullterm fetus.

[A study of 16 alpha OH-DHA and 16 alpha OH-pregnenolone in feto-placental unit (author's transl)]

Serum levels of total 16 alpha-hydroxydehydroepiandrosterone (16 alpha-OH-DHA) and 16 alpha-hydroxy-pregnenolone (16 alpha-OH-P5) which are considered to be a fetal origin have not been well documented. Radioimmunoassays using specific antisera against 16 alpha-PH-DHA-7-CMO-BSA and 16 alpha-OH-P5-#-succinate-BSA were developed and serum concentrations of these steroids in normal men and women, maternal peripheral vein (MV) during pregnancy, umbilical artery and umbilical vein at delivery were measured. Labeled 16 alpha-hydroxylated steroids were synthesized by microbiological method. The concentrations of 16 alpha-OH-delta 5-steroids were increased as pregnancy progresses. Both steroid levels in cord serum were statistically higher than those in MV. In the case of intrauterine fetal death and anencephalic pregnancy, significantly low levels of both steroids in MV and cord blood were found. On the other hand, pregnancy with placental sulfatase deficiency, showed high levels both in MV and cord vein. It is interesting to not that in normal pregnancy, maternal 16 alpha-OH-DHA levels correlated well with that of 16 alpha-OH-P5. However, in pregnancy with anencephalic fetus, there was no correlation between the levels of two steroids. From the results of in vitro experiment using placental tissue, 16 alpha-OH-progesterone was formed from labeled 16 alpha-OH-P5, whereas no metabolite was noticed when fetal adrenal tissue was used. From these in vitro and in vivo studies, a significance of the measuring of serum 16 alpha-OH-DHA and 16 alpha-OH-P5 during pregnancy is discussed.

Stimulatory effect of chlorpromazine on prolactin secretion in anencephalic infants

The effect of chlorpromazine on serum levels of PRL was studied in two anencephalic infants without identifiable hypothalamic tissue. After a single im injection of chlorpromazine, serum concentrations of PRL rose about 3-fold. This result indicates that chlorpromazine stimulates PRL release by directly acting on the pituitary gland in humans.

[The role and secretion of prolactin in the human fetus and neonate (author's transl)]

Prolactin (PRL), growth hormone (GH), and estradiol-17 beta (E2-17 beta) levels were measured by radioimmunoassay in umbilical venous serum from 118 full term normal infants and 11 anencephalic infants. In anencephalic infants, the concentration of GH:2.4 +/- 1.6 ng/ml (mean +/- SD, n = 11) and E2-17 beta:2.3 +/- 1.4 ng/ml (n = 6) were significantly lower than those in normal infants (GH: 16.5 +/- 9.0 ng/nl n = 65; E2-17 beta:12.4 +/- 8.0 ng/ml, n = 108). There was no significant difference of PRL levels between normal infants (324 +/- 118 ng/ml, n = 118) and anencephalic infants (253 +/- 86 ng/ml, n = 10). There was significant positive correlations between PRL and E2-17 beta levels in normal infants (p less than 0.01), and was significant negative correlation between PRL levels and birth weight (p less than 0.01). These results suggested that PRL secretion is affected by estrogens during fetal period and fetal PRL has some effects for the regulation of fetal growth as somatogenic hormone.

[An evaluation of the plasma dynamics of the 16 alpha-hydroxy steroids in fetuses and neonates (author's transl)]

This study was done to evaluate the plasma dynamics of 16 alpha-hydroxy dehydroepiandrosterone (16 alpha OH-DHA),-pregnenolone (16 alpha OH-Preg) and -progesterone (16 alpha OH-Prog) in both the unconjugated and conjugated forms in fetuses and neonates. A comparison between second and third trimester umbilical plasma levels revealed that conjugated 16 alpha OH-DHA was already elevated in the second trimester, and both 16 alpha OH-Preg and 16 alpha OH-Prog were increased. At normal deliveries, all of the steroid levels in umbilical plasma, especially conjugates, were consistently higher than in maternal plasma. There were definite correlation between umbilical arterial and venous unconjugated and conjugated 16 alpha OH-Prog and conjugated 16 alpha OH-DHA, while no correlation of 16 alpha OH-Preg. Further, umbilical arterial 16 alpha OH-Preg showed a distinct correlation when compared to umbilical venous 16 alpha OH-Prog, suggesting that 16 alpha OH-DHA and 16 alpha OH-Preg are fetal in origin, while 16 alpha OH-Prog is synthesized in the placenta from 16 alpha OH-Preg. All of the steroid levels in the neonatal peripheral plasma up to and including the fifth post partum day were consistently higher than umbilical plasma levels. In low birth weight neonates, the umbilical plasma and peripheral neonatal plasma 16 alpha OH-Preg were consistently higher than levels found in normal birth weight neonates, while 16 alpha OH-Prog and 16 alpha OH-DHA did not show a statistical difference between low and normal birth weight neonates. The significance of these steroid dynamics and their physiological role are discussed.

Thyroid-pituitary function in eight anencephalic infants

The function of the thyroid pituitary axis was investigated in 8 anencephalic infants with no hypothalamus. Thyrotrophin (TSH), thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyrone (reverse T3 and rT3) were measured in the cord blood in 5 cases and during the first 4 h of life in 3 cases. TSH response to synthetic thyrotrophin-releasing hormone (TRH) (200 microgram iv) was carried out in two cases and thyroid hormone response to bovine TSH (5 IU iv) was evaluated in 3 cases. The following results wre obtained: 1) The pituitary gland was found in all infants and the thyroid was normal both grossly and by microscopic sections. 2) TSH levels at birth were normal but there was no spontaneous post-delivery surge. 3) T4 and T3 values at delivery were within normal range, but no T3 increase was present after birth. rT3 levels at birth were higher than normal in 3 cases. 4) Administration of TRH caused a marked and rapid TSH release. 5) Thyroid hormone response to TSH was normal. The present findings suggest that in the anencephalic foetus both pituitary TSH-secreting cells and the thyroid gland do develop despite the absence of the hypothalamus and are able to function if adequately stimulated.

[Remarks suggested by a case of anencephaly with a different Pi type in fetal and maternal blood (author's transl)]

In an African woman who gave birth to an anencephalic foetus at the 28th week, the maternal blood (S.M.), the amniotic fluid (L.A.) and the cord blood (S.C.) were studied. The same fluids from a normal pregnancy and the blood from a normal woman of the same age were also studied. Alpha 1 antitrypsin (A1AT) was assayed: it was similar in the subject and the controls. When the phenotype of the A1AT was examined it was found to be ML in S.C., MM in S.M. and L.A. (suggesting a maternal origin of the A1AT of the L.A.). This distribution of the fraction of A1AT was similar for S.M. and L.A. (a new finding) but different for the S.C. (was the latter a result of the anencephaly?).

Low somatomedin activity in cord serum from infants with intrauterine growth retardation

Somatomedin activity was determined by the simultaneous incorporation of 35S-sulfate and 3H-methyl thymidine into costal cartilage from hypophysectomized rats in cord sera from term and preterm infants and infants with intrauterine growth retardation. Mean Sm activity by sulfate incorporation was 0.49 +/- 0.04, 0.35 +/- 0.05, and 0.09 +/- 0.03 units/ml (+/- SE) in the term, preterm, and IGR cord sera, respectively. The levels for each group were significantly different from each of the other groups. There was no significant difference between the mean Sm activity by thymidine incorporation in cord sera from term (0.92 +/- 0.09 units/ml) and preterm (0.87 +/- 0.08 units/ml) infants. These levels were significantly higher, however, than the Sm activity by sulfate incorporation for the respective groups, P less than 0.001 for both groups. The mean Sm activity by thymidine incorporation in cord sera for IGR infants was 0.36 +/- 0.13 units/ml, and significantly lower than the levels in cord sera of term and preterm infants (P less than 0.01). Inhibition of Sm activity by mixing cord serum and pooled adult serum was found in one of the two cord specimens tested from IGR infants. The low levels of Sm activity in cord sera from IGR infants may reflect altered intrauterine nutrition. The discrepancy in the thymidine and sulfate incorporation by the costal cartilage bioassay for term and preterm cord sera might result from Sm-like factors in human fetal serum with greater mitogenic or thymidine transport activity compared to the activity for proteoglycan synthesis in cartilage.

[Prenatal diagnosis of congenital defects through the determination of alpha fetoprotein]

The prenatal diagnosis of neural tube defects is based on elevated alpha-fetoprotein (AFP) concentrations in the amniotic fluid as well as in the maternal serum. Amniocentesis has to be performed in those women who already gave birth to an affected child and have the high risk to bear another. On the other hand more than 90% of the newborns with anencephaly and spina bifida are born by mothers without any increased risk in anamnesis. Therefore maternal serum screening is indicated in all pregnant women to rule out a neutral tube defect. The pittfalls of a general serum screening are discussed an a survey of the datas from different international centers is presented.

[Ontogenesis of hypothalamic control of adenohypophyseal secretions in the human foetus (author's transl)]

The endocrine glands of the human foetus are active early in gestation, and various foetal and placental hormonal contributions are essential for growth and sexual differentiation. 1. The anterior pituitary gland has the ability to synthesize, store and secrete hormones early in gestation. The patterns of change in plasma concentrations of hGH (Fig. 1), ACTH, LH and FSH (Fig. 2) during gestation indicate that secretion is at a maximum at mid-gestation, followed by a progressive decrease towards term. The high levels at mid-gestation can be interpreted as due simultaneously to a high secretion rate, low peripheral catabolism and absence of feedback mechanism. In contrast, the secretions of PRL (Fig. 1) and TSH are moderate at mid-gestation and only increase in the last trimester of gestation. 2. Effective control by the central nervous system (CNS) of the pituitary secretions is still immature at mid-gestation. The presence in the foetal hypothalamus of releasing factors such as LRF (Fig. 5) and TRF, and of somatostatin (Fig. 6), a growth hormone release inhibiting factor (GIF), has been established. TRF and GIF, but not LRF, are also present in the cerebral cortex. It has been postulated that, early in life, relatively autonomous and unrestrained secretion of hypothalamic hypophysiotropic releasing factors occurs, and that, later in development, there is a maturation of inhibitory or restraining influences mediated via the CNS (feedback mechanisms) that modulates the secretion of the foetal adenohypophyseal hormones (Fig. 3 and 4). 3. Observations made with anencephalic newborn confirm that a functional hypothalamus is necessary during foetal life for the secretion of each of the hormones of the anterior pituitary gland with the exception of PRL, the secretion of which is normal in anencephaly. Although somatostatin probably participates in the regulation of hGH during foetal life, it appears evident from the anencephaly data that this regulation can only be fully understood by postulating the existence of a growth hormone releasing factor (GRF).

Some problems of alpha-fetoprotein screening

In two years of a routine screening programme for the detection of neural-tube defects over 6000 women had serum-alpha-fetoprotein (A.F.P.) measured. As a result, 80 women carrying live singleton fetuses were offered amniocentesis under ultrasound control. All neural-tube defects detected at birth were recorded and necropsies were done routinely on abortuses, thus permitting evaluation of the screening programme in terms of false negatives and false positives. 16 amniotic-fluid A.F.P.s were abnormal, 1 for an unaffected fetus; and 2 others were normal for fetuses which had closed lesions. At the serum-A.F.P. stage, 3 lesions were missed. The detection-rate compares favourably with those of other series. However, in a pilot study, routine ultrasonic assessment of gestation yielded a substantial proportion of cases where a serum-A.F.P. deemed normal or abnormal when gestation was assessed clinically would have been misleading. Loss of normal fetuses subsequent to amniocentesis (5 in this series) also has to be taken into account.

Avoidance of anencephalic and spina bifida births by maternal serum-alphafetoprotein screening

Screening of 11 585 pregnant women between 16 and 20 completed weeks' gestation for raised serum-alphafetoprotein (A.F.P.) levels showed that the birth of 81.4% of babies with open neural-tube defects could be avoided. The screening test was sensitive enough to detect 93% of those affected and serum-A.F.P. levels above the point at which intervention shouldbe considered were found in 1.7% of pregnancies. After 75.2% of false-positives had been excluded by ultrasonography or by a repeat of the serum test, only 0.63% of pregnancies proceeded to amniocentesis, 46.6% of amniocenteses showed raised amniotic A.F.P. levels due to fetal abnormality. Fetal loss by abortion or perinatal death after amniocentesis occurred in 0.034% of pregnancies screeded, 75% being associated with threatened abortion before amniocentesis. There were no terminations of normal pregnancies due to false-positive amniotic A.F.P. results. It is concluded that voluntary maternal serum-A.F.P. screening has a valuable role in antenatal care.

[Alpha-fetoprotein, HPL, ostriol and SP1 concentrations in prostaglandin-induced mid-trimester abortions (author's transl)]

Maternal serum concentrations of AFP, HPL, SP1 and Estriol were measured in the course of prostaglandin-induced abortions. Termination of pregnancy between the 13th and 25th week of pregnancy was done for medical reasons. Patients were treated with PGE2, PGF2alpha and with 16-phenoxy-PGE2-methansulfonamid, respectively. Prostaglandins were administered systemically, i. e. intravenously. Current measurement of HPL and AFP-concentrations showed a contrary sense. These changes of concentrations were related to fetal death and membrane rupture in some cases as is demonstrated in four diagrams. Typical and sharply decreasing values of Estriol followed fetal death in patients with intact pregnancies before. As for an anencephalic fetus, AFP-concentrations increased slightly too, HPL values decreased like in other abortions. Only minimal changes of SP1 concentrations were found generally in all patients and during abortion time.