Maternal and fetal alphafetoprotein (AFP) levels at term. Relation to sex, weight and gestation of the infant

Serum alpha-fetoprotein (AFP) was measured in maternal, cord arterial and venous blood. Samples were collected at the time of vaginal delivery from 105 women at 36-42 weeks' gestation. There was a significant correlation between maternal, cord arterial and venous AFP. Umbilical cord arterial and venous AFP levels were considerably higher in male infants than in females. Umbilical AFP levels declined with lengthening gestation and increasing birthweight for both male and female infants and a similar pattern was seen in the mother. Fetal AFP levels were significantly higher in subjects giving birth at 40 weeks whose infants had a birthweight below the population mean vis-à-vis those above the mean. It is concluded that the absolute size of the fetus as well as gestational age may play a significant role in determining maternal and fetal AFP concentration.     

Different maternal serum hCG levels in pregnant women with female and male fetuses: does fetal hypophyseal--adrenal--gonadal axis play a role?

Fetal gender has a significant effect on maternal and cord blood hCG levels, particularly during the last trimester of the pregnancy. However, the reason for this difference is obscure. The aim of the present study was to investigate whether term fetal hypophyseal - adrenal - gonadal axis differs between female and male fetuses thereby causing different hCG levels. The study consisted of 60 women with singleton pregnancies in the third trimester. Thirty-one pregnant women were carrying female fetuses, whereas 29 were carrying male. Human chorionic gonadotropin (hCG), estradiol, progesterone, testosterone, dehydro-epiandrosteron-sulfate (DHEAS), prolactin and growth hormone levels were measured in maternal serum and umbilical cord blood. In female bearing pregnancies maternal and cord blood hCG levels were significantly higher than in male bearing pregnancies (P<0.001). Maternal and cord blood estradiol, progesterone, testosterone, DHEAS, prolactin and growth hormone levels were not significantly different in either fetal gender. When all patients were considered as a group there were no correlations between fetal hCG levels and any of the measured hormones. Term fetal DHEAS, estrogen, progesterone, testosterone, growth hormone and prolactin levels do not contribute to different hCG levels between female and male fetuses. It is possible that fetal hypophyseal-adrenal gonadal axis does not play a central role as the cause of different hCG levels.     

Human chorionic gonadotropin in maternal serum in relation to fetal gender and utero-placental blood flow

BACKGROUND: To investigate whether fetal gender differences in human chorionic gonadotropin (hCG) in maternal serum and the presence of hCG receptors in the wall of the uterine arteries influence the utero-placental blood flow. METHOD AND MATERIAL: Sixty-six healthy women with singleton uncomplicated pregnancies were examined at 8-10, 16-19 and 31-37 weeks of gestation. The pulsatility index (PI) was measured in the uterine arteries, simultaneously with sampling of peripheral maternal blood for hCG determination. Volume flow in the uterine arteries was determined in the second and third trimesters only. RESULTS: In the first and second trimesters no gender differences in the hCG levels were observed. From the second to the third trimester the hCG levels increased significantly in pregnancies with female fetuses (P < 0.05), while in pregnancies with male fetuses the hCG levels tended to decline. The PI declined significantly from the first to the third trimester in both genders (P < 0.001). In the first and third trimesters no gender differences were seen. In the second trimester the PI values were significantly higher in pregnancies with male fetuses than in those with female fetuses (P < 0.02). The flow volume increased significantly in both genders from the second to the third trimester (P < 0.001). In the third trimester the flow volume was higher in pregnancies with female fetuses than in those with male fetuses (P = 0.05). CONCLUSION: The gender differences in uterine artery PI and flow volume were not correlated to maternal serum hCG levels.     

Maternal serum unconjugated oestriol and human chorionic gonadotrophin levels in twin pregnancies: implications for screening for Down's syndrome.

OBJECTIVE--To investigate maternal serum unconjugated oestriol (uE3) and human chorionic gonadotrophin (hCG) levels in twin pregnancies and to consider the implications of the results for antenatal screening for Down's syndrome. DESIGN--Measurement of maternal serum uE3 and hCG levels from 15-22 weeks of gestation in twin and singleton pregnancies. Previously available maternal serum alpha-fetoprotein (AFP) levels were also presented. SETTING--Stored serum samples collected from women receiving routine antenatal care in Oxford were used. SUBJECTS--200 women with a twin pregnancy and, for each, three singleton control pregnancies matched for gestational age (same completed week of pregnancy) and duration of storage of the serum sample (same calendar quarter). RESULTS--The median uE3, hCG and AFP levels in the twin pregnancies were respectively, 1.67 (95% CI 1.56-1.79), 1.84 (95% CI 1.64-2.07) and 2.13 (95% CI 1.97-2.31) multiples of the median (MoM) for singleton pregnancies at the same gestational age. The variance of values for the three serum markers (expressed in logarithms), and the correlation coefficients between any two, were similar in the twin and singleton pregnancies. CONCLUSION--In maternal serum screening programmes for Down's syndrome dividing uE3, hCG and AFP MoM values in twin pregnancies by the corresponding medians for twin pregnancies will, in expectation, yield a similar false-positive rate in twin pregnancies as in singleton pregnancies.     

Correlation between fetal sex and human chorionic gonadotropin in peripheral maternal blood and amniotic fluid in second and third trimester normal pregnancies.

BACKGROUND: To study the correlation between fetal sex and human chorionic gonadotropin (hCG) in maternal blood and amniotic fluid. METHOD AND MATERIAL: One hundred and thirty uncomplicated pregnancies, 82 of whom were at sixteen and 48 at thirty-five weeks of gestation. RESULTS: The hCG levels were significantly higher in maternal serum than in amniotic fluid. At 16 weeks there were no sex-related differences in the hCG levels, either in maternal blood or in amniotic fluid. At 35 weeks the hCG levels in maternal blood were significantly higher in pregnancies with female fetuses than in those carrying male fetuses (p<0.004), while in amniotic fluid the hCG levels tended to be slightly higher in the female group than in the male. In pregnancies with female fetuses the hCG levels in maternal blood were significantly higher at 35 than at 16 weeks (p<0.02), while in pregnancies with male fetuses the levels were highest at 16 weeks. For both sexes the hCG levels in amniotic fluid were significantly higher at 16 than at 35 weeks of pregnancy (p<0.001). Whereas a significant correlation between hCG levels in maternal blood and amniotic fluid was seen at 16 weeks of gestation for both sexes (p<0.01 and R value 0.45 for males and 0.41 for females), no correlation was observed at 35 weeks. CONCLUSION: This study shows a significant correlation between hCG and fetal sex at third trimester of gestation only, possibly caused by a gender factor and a shift in synthesis and/or in metabolism of hCG from the second to the third trimester.     

Human chorionic gonadotropin and testosterone in normal and preeclamptic pregnancies in relation to fetal sex

OBJECTIVE: The aim of the present study was to evaluate the effects of fetal gender on serum human chorionic gonadotropin (hCG) and testosterone in normotensive and preeclamptic pregnancies. METHODS: The study consisted of 137 women with singleton pregnancies in the third trimester. Seventy-three pregnancies were uncomplicated; among those were 35 male and 38 female fetuses. Sixty-four pregnancies were complicated by preeclampsia; among those were 33 male and 31 female fetuses. Human chorionic gonadotropin and total testosterone were measured in maternal peripheral blood. RESULTS: In male-bearing pregnancies, maternal hCG and testosterone serum levels were significantly higher in preeclamptic than normotensive mothers (P <.001). In female-bearing pregnancies, testosterone levels were significantly higher in preeclamptic than normotensive mothers (P <.001), whereas the hCG levels were not significantly different. Male-bearing preeclamptic women had significantly higher testosterone levels than female-bearing preeclamptic women (P <.02), whereas the hCG levels were not significantly different. In uncomplicated pregnancies the hCG levels were significantly higher in female-bearing than in male-bearing mothers (P <.005), whereas the testosterone levels were not significantly different. CONCLUSION: In preeclamptic pregnancies with male fetuses, the maternal serum hCG levels were significantly higher than in uncomplicated pregnancies. Total testosterone levels were significantly higher in pregnancies with either gender and significantly higher in male-bearing than in female-bearing pregnancies. This may indicate an androgen influence on the pathophysiologic mechanism of preeclampsia.     

Maternal smoking: age distribution, levels of alpha-fetoprotein and human chorionic gonadotrophin, and effect on detection of Down syndrome pregnancies in second-trimester screening

OBJECTIVES: To study the levels of maternal serum alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) in the second trimester in smokers and non-smokers with unaffected and Down syndrome pregnancies; to examine the rate of smoking in different maternal age groups in a population having routine prenatal screening; and to assess the effect of smoking on the detection rates for Down syndrome and corresponding false-positive rates, both overall and in different maternal age groups. METHODS: Information on maternal smoking status, maternal age and serum marker levels was collected from case note searches and the screening programme database on 2272 unaffected singleton pregnancies, 36 unaffected twin pregnancies and 103 singleton Down syndrome pregnancies. RESULTS: In unaffected pregnancies the smokers had a median age 3.3 years less than the non-smokers, while in the Down syndrome cases the corresponding age difference was 2.0 years. Median analyte levels in multiples of the median (MoM) in the unaffected singleton pregnancies were, for non-smokers: AFP=0.97, hCG=1.04; and for smokers, AFP=1.04, hCG=0.80. In the Down syndrome pregnancies the medians were, for non-smokers: AFP=0.69, hCG=2.49; and for smokers, AFP=0.70, hCG=1.53. Correction for smoking status gave median MoMs of 1.0 for both AFP and hCG in the unaffected pregnancies in both smokers and non-smokers. In the Down syndrome cases the corrected medians were, for non-smokers: AFP=0.67, hCG=2.29; and for smokers, AFP=0.73, hCG=1.99. Before correction for maternal smoking the overall detection rate for Down syndrome was 66.7% with a false-positive rate of 6.2%. After correction the detection rate was 67.7% with a false-positive rate of 4.9%. Between the smoking and non-smoking groups there was a significant difference in the detection rate (37.5% versus 76.0%) and the false-positive rate (1.8% versus 8.1%), which disappeared after correction for smoking status (detection rate 62.5% versus 69.3%, false-positive rate 3.9% versus 5.4%). No evidence of a lower incidence of Down syndrome in smokers was found. CONCLUSIONS: While correcting AFP and hCG results for maternal smoking status will have little impact on the overall detection rate for Down syndrome, it may reduce the false-positive rate and will improve the accuracy of the risks given to individual women.     

Maternal serum alpha-fetoprotein and birth weight in twin pregnancies.

In 102 twin pregnancies the mean birth weight of each pair showed a statistically significant negative association with maternal serum alpha-fetoprotein (AFP) levels early in pregnancy. Women with AFP levels of four or more times the median value for singleton pregnancies gave birth to infants with a median birth weight 660 g less than that of infants born to women with AFP levels between 1.0 and 1.5 times the median for singleton pregnancies. Maternal serum AFP has been shown to be an early predictor of low birth weight delivery in singleton pregnancies. Our results indicate that this is also true in twin pregnancies.     

Does fetal gender affect cytotrophoblast cell activity in the human term placenta? Correlation with maternal hCG levels

BACKGROUND: Pregnant women with female fetuses have higher maternal serum human chorionic gonadotropin (hCG) levels than pregnant women with male fetuses. Ki-67, a cell proliferation and activity marker, is confined mostly in the nuclei of villous cytotrophoblasts of the human placenta. In this study, we examined the effect of fetal gender on the cytotrophoblast cell activity in human term placenta, with special regard to maternal serum and cord blood hCG levels. METHODS: Thirty-four uncomplicated, singleton, term pregnancies (17 male and 17 female fetuses) were recruited in the study. hCG was measured in maternal peripheral serum and umbilical cord blood. Placental samples were collected in each patient during the cesarean section. Cytotrophoblast cell activity was measured by using immunohistochemistry for Ki-67 antigen. Ki-67 staining index values of the cytotrophoblasts were compared between the female and male placentas. RESULTS: Maternal serum and cord blood hCG levels were higher in pregnant women with female fetuses than in those carrying male fetuses. There was no sex difference in Ki-67 immunostaining rates of the cytotrophoblast cells. There was no correlation between maternal serum and cord blood hCG levels and Ki-67 staining index values of the cytotrophoblast cells. CONCLUSIONS: The difference in maternal serum and cord blood hCG levels in correlation with the fetal gender is not associated with cytotrophoblast cell activity in the human term placenta. The gender of the fetus does not seem to affect the regulation of cytotrophoblast cell proliferation.     

Associations between the levels of soluble (pro)renin receptor in maternal and umbilical cord blood and hypertensive disorder of pregnancy

IntroductionThe prorenin (PR) receptor [(P)RR] contributes to the regulation of the tissue renin-angiotensin system (RAS) and Wnt signaling, which is involved in embryogenesis and the pathological progression of malignant tumors and diabetes mellitus. Placental (P)RR is significantly upregulated in placental tissues from preeclamptic women. However, because it cannot be examined during pregnancy, the chronological relationship between the acceleration of tissue RAS and the disease state of hypertensive disorder of pregnancy (HDP) has not been reported. In this study, we examined whether chronological changes in placental tissue RAS can be assessed by measuring soluble (P)RR [s(P)RR].MethodsWe obtained maternal and umbilical cord blood samples from 517 pregnant women (441 singleton and 76 twin pregnancies). The concentrations of s(P)RR and prorenin (PR) were measured using enzyme-linked immunosorbent assays.ResultsMultivariate analysis showed that maternal serum s(P)RR levels were significantly higher in patients with HDP or fetal growth restriction (FGR) and were positively correlated with serum PR levels. Furthermore, the maternal s(P)RR level was significantly higher in HDP with severe hypertension and after the onset of HDP. However, maternal s(P)RR levels were not affected by the severity of proteinuria. Serum s(P)RR levels in umbilical cord blood of singleton pregnancies were significantly correlated with gestational week at delivery and PR level.DiscussionMaternal serum s(P)RR concentrations may reflect acceleration of tissue RAS in the placenta and blood pressure severity; however, the umbilical serum s(P)RR concentration was not affected by maternal HDP.     

SRY-specific cell free fetal DNA in maternal plasma in twin pregnancies throughout gestation

Objectives

Levels of SRY-specific cell free fetal DNA (SRY-cffDNA) in maternal plasma were investigated in twin pregnancies with two male fetuses versus one male and one female fetus and singleton male pregnancies during second and third trimester. The aim was to evaluate at which gestational age the amount of SRY-cffDNA reflects the number of fetuses and placentas respectively.

Methods

251 venous blood samples were analyzed from a total of 178 women with male or mixed-gender twin pregnancies and male singleton pregnancies in the second and the third trimester. The concentration of SRY-cffDNA was determined by quantitative real time PCR using the Y-chromosome specific SRY assay. For statistical analysis these three groups were divided into four subgroups according to their gestational age.

Results

During second trimester levels of SRY-cffDNA showed no differences between twin and singleton pregnancies. After 28 weeks SRY-cffDNA of male twin pregnancies was significantly increased compared to singleton male pregnancies and mixed-gender twin pregnancies with no differences between the latter two.

Conclusion

The level of SRY-cffDNA in maternal serum of twin pregnancies reflects the number of fetuses only during the third trimester. Hence its use as a diagnostic tool for complications related to altered SRY-cffDNA levels in twin pregnancies should be evaluated at different weeks of gestation, especially during the second trimester.     

Relation between serum uric acid and plasma adenosine levels in twin pregnancies

OBJECTIVE: To examine the relationship between plasma adenosine and serum uric acid levels in women with singleton and twin pregnancies. METHODS: We sampled maternal arterial blood and measured serum uric acid and plasma adenosine levels in 22 singleton pregnancies and nine twin pregnancies at 33 to 38 weeks' gestation. RESULTS: The average plasma adenosine levels were 0.31 +/- 0.12 micromol/L in the singleton pregnancy group and 0.45 +/- 0.09 micromol/L in the twin pregnancy group (P <.001). The mean serum uric acid level in women with twin pregnancy was 5.7 +/- 0.44 mg/dL which was higher than that in the singleton pregnant women (4.4 +/- 0.69 mg/dL, P <.001). Positive correlations were found between serum uric acid and plasma adenosine levels in both the singleton (r(2) = 0.54, P <.001) and the twin pregnancy groups (r(2) = 0.65, P =.009). Moreover, there was also a significant correlation between serum uric acid and plasma adenosine levels overall (r(2) = 0.66, P <.001). CONCLUSION: Our results suggest that higher adenosine levels are a contributing source of hyperuricemia in twin pregnancies.     

Comparative maternal lactate-pyruvate ratios in singleton and twin pregnancies and in babies delivered at term.

The lactate-pyruvate (L/P) ratio was used for assessment of anaerobic metabolism, hypoxia or oxygen debt in uterine contractile muscle during labour and immediately after parturition. The mean blood lactate level was significantly higher in mothers with twin pregnancies (P<0.001) than in singleton pregnancies at term. L/P ratios were markedly elevated in established labour both in mothers of singleton as well as in mothers of twin pregnancies and were also higher in cord blood of the twins than those of singleton babies (P<0.001). The twins delivered second had higher L/P ratios (P<0.05) than the leading twins.     

Cord blood thyroid-stimulating hormone level in twin pregnancy

BACKGROUND: Cord blood thyroid-stimulating hormone level is elevated among neonates who undergo more perinatal stress. The aim of this study was to investigate the effect of twin pregnancy on the cord blood thyroid-stimulating hormone level. METHODS: The study group consisted of 24 910 singleton and 543 twin neonates over a 4-year period. The effect of twin pregnancy on the cord blood thyroid-stimulating level was evaluated. Linear regression analysis was used to control for the effect of mode of delivery, birth weight, and infant sex. RESULTS: The median cord blood thyroid-stimulating hormone levels (interquartile range) in the singletons and in the twins were 5.8mIU/l (4.2-8.6) and 5.6mIU/l (4.3-7.5), respectively. Linear regression analysis revealed no significant difference between singleton and twin cord blood thyroid-stimulating hormone levels (p = 0.23). Cord thyroid-stimulating hormone levels tended to be higher in second-born twins (p = 0.08) and monochorionic twins (p = 0.097) compared with singleton neonates. Twins with more than 20% weight discordance were associated with a significantly higher cord blood thyroid-stimulating hormone level (p = 0.035). CONCLUSION: Cord blood thyroid-stimulating hormone level is elevated in some subgroups of twins who are at higher risk of adverse perinatal outcomes. However, the overall effect of multiple pregnancy on the cord blood thyroid-stimulating hormone level is small. Cord blood thyroid-stimulating hormone screening for congenital hypothyroidism is also valid in twin pregnancies.     

Relationship between the cortisol levels in umbilical cord blood and neonatal RDS/TTN in twin pregnancies

Objective: Twin neonates have a higher risk of respiratory complications, such as respiratory distress syndrome (RDS) and transient tachypnea of the newborn (TTN), than singleton neonates. The purpose of this study was to evaluate the relationship between the cortisol levels in the umbilical cord and neonatal RDS/TTN in twin pregnancies.

Methods: We analyzed data obtained from 106 neonates (53 twin pairs), comprising 33 dichorionic twin (DCT) and 20 monochorionic twin (MCT) gestations. All infants were delivered via scheduled cesarean section without labor. We measured the cortisol levels in umbilical vein blood using enzyme-linked immunosorbent assay.

Results: The cortisol levels in the umbilical vein were significantly lower in the RDS/TTN group than in the no RDS/TTN group (p = 0.004). The umbilical cortisol levels in the TTN group were between the values observed in the RDS group and no RDS/TTN group. We subsequently analyzed the cut-off cortisol values for RDS/TTN and observed higher accuracy in the DCTs than in the MCTs.

Conclusions: Neonates who develop RDS/TTN have significantly lower cortisol levels in the umbilical cord at birth than no RDS/TTN neonates in twin pregnancies. When applying these data in clinical practice, physicians should pay attention to differences based on chorionicity.     

Association between second-trimester isolated high maternal serum maternal serum human chorionic gonadotropin levels and obstetric complications in singleton and twin pregnancies

OBJECTIVE: The purpose of this study was to examine the clinical significance of high maternal serum human chorionic gonadotropin levels in the second trimester in singleton and twin pregnancies within the Ontario maternal serum screening program. STUDY DESIGN: The study group comprised 564 women with singleton pregnancies with total maternal serum human chorionic gonadotropin levels of > or =4.0 multiples of the median (MoM) and serum marker alpha-fetoprotein levels of <2.0 MoM. The cases were matched with 1692 control subjects who had both serum marker alpha-fetoprotein levels and maternal serum human chorionic gonadotropin levels of <2.0 MoM. The second part of the study comprised 93 twin pregnancies with maternal serum human chorionic gonadotropin levels of > or =5.0 MoM and serum marker alpha-fetoprotein levels of <4.0 MoM; the control group (n = 1496) had serum marker alpha-fetoprotein levels of <4.0 MoM and maternal serum human chorionic gonadotropin levels of <5.0 MoM. The final part of the study included 25 women with extremely high maternal serum human chorionic gonadotropin levels (> or = 14;10 MoM). RESULTS: Of the singleton pregnancies with maternal serum human chorionic gonadotropin levels of > or = 14;4.0 MoM, 22.5% had severe adverse obstetric outcomes, compared with only 10.9% of the matched control population (P =.001). Women with markedly elevated maternal serum human chorionic gonadotropin levels had significantly increased risks of having spontaneous miscarriage, small-for-gestational-age infants, pregnancy-associated hypertensive disorder, and preterm delivery. Of the women with twin pregnancies with high maternal serum human chorionic gonadotropin levels (> or =5.0 MoM), 71% had at least one complication (such as miscarriage and preterm delivery) compared with 55.3% in the control group. Finally, 23 of 25 women with extremely high maternal serum human chorionic gonadotropin levels (> or = 14;10 MoM) had serious adverse outcomes (such as fetal abnormalities, pregnancy-associated hypertensive disorder, premature separation of placenta, intrauterine growth restriction, neonatal respiratory distress syndrome, and neonatal jaundice). CONCLUSION: Pregnancies with an elevated maternal serum human chorionic gonadotropin level are associated with adverse obstetric outcomes. Increased maternal and fetal surveillance is warranted in these pregnancies.     

Comparative analysis of the maternal and umbilical interleukin-8 levels in normal pregnancies and in pregnancies complicated by preeclampsia with intrauterine normal growth and intrauterine growth retardation

Objectives.?The aim of this study was to determine the maternal and umbilical cord serum levels of interleukin-8 (IL-8) in pregnancies complicated by preeclampsia with intrauterine normal growth and intrauterine growth retardation (IUGR), and in normotensive pregnancies.

Patients and methods.?The study was carried out on 15 patients with singleton pregnancies complicated by preeclampsia with appropriate for gestational age weight infants and 12 pregnant patients with preeclampsia complicated by IUGR. The control group consisted of 10 healthy normotensive delivering patients with singleton uncomplicated pregnancies. Maternal and umbilical serum IL-8 concentrations were estimated using the ELISA method.

Results.?There were no statistically significant differences in patient profiles between the groups. Systolic and diastolic blood pressure and mean arterial blood pressure were higher in the study groups in comparison with the control group. Lower birth weight and lower gestational age at birth were observed in the group of patients with preeclampsia complicated by IUGR. Increased maternal and umbilical serum levels of IL-8 were found in both preeclamptic patient groups in comparison with the control group. The umbilical cord blood concentrations of IL-8 in all groups of patients tended to be higher in comparison with the maternal blood.

Conclusions.?It seems that these higher IL-8 concentrations may be associated with apoptosis, inflammation, neutrophil activation, endothelial cell damage and dysfunction, and increased endothelial permeability. They may also participate in an attempt to compensate for the imbalanced apoptosis and vascular resistance. Our findings suggest a possible significant role of IL-8 in the pathogenesis and sequelae of preeclampsia, especially in preeclamptic pregnancies complicated by IUGR.     

Comparative analysis of the maternal and umbilical interleukin-8 levels in normal pregnancies and in pregnancies complicated by preeclampsia with intrauterine normal growth and intrauterine growth retardation.

OBJECTIVES: The aim of this study was to determine the maternal and umbilical cord serum levels of interleukin-8 (IL-8) in pregnancies complicated by preeclampsia with intrauterine normal growth and intrauterine growth retardation (IUGR), and in normotensive pregnancies. PATIENTS AND METHODS: The study was carried out on 15 patients with singleton pregnancies complicated by preeclampsia with appropriate for gestational age weight infants and 12 pregnant patients with preeclampsia complicated by IUGR. The control group consisted of 10 healthy normotensive delivering patients with singleton uncomplicated pregnancies. Maternal and umbilical serum IL-8 concentrations were estimated using the ELISA method. RESULTS: There were no statistically significant differences in patient profiles between the groups. Systolic and diastolic blood pressure and mean arterial blood pressure were higher in the study groups in comparison with the control group. Lower birth weight and lower gestational age at birth were observed in the group of patients with preeclampsia complicated by IUGR. Increased maternal and umbilical serum levels of IL-8 were found in both preeclamptic patient groups in comparison with the control group. The umbilical cord blood concentrations of IL-8 in all groups of patients tended to be higher in comparison with the maternal blood. CONCLUSIONS: It seems that these higher IL-8 concentrations may be associated with apoptosis, inflammation, neutrophil activation, endothelial cell damage and dysfunction, and increased endothelial permeability. They may also participate in an attempt to compensate for the imbalanced apoptosis and vascular resistance. Our findings suggest a possible significant role of IL-8 in the pathogenesis and sequelae of preeclampsia, especially in preeclamptic pregnancies complicated by IUGR.     

The relation between maternal plasma alpha-fetoprotein and birth weight in twin pregnancies.

In the course of routine screening for neural tube defects, maternal plasma alpha-fetoprotein (AFP) was measured between 15 and 23 weeks of gestation in 64 twin pregnancies. Women with AFP levels more than twice the median for singleton pregnancies gave birth to infants with significantly decreased birth weights. Women with AFP less than the median also tended to produce twins with decreased birth weights. The distribution of gestations at delivery suggested that in twin pregnancies low AFP values gave an early warning of growth retardation while high values signal possible premature delivery.     

Elevated maternal plasma corticotropin releasing hormone levels in twin gestation

The placenta secretes large amounts of the hypothelamic hormone, corticotropin releasing hormone (CRH) into the maternal and fetal circulation during pregnancy. We and other investigators have shown that during normal pregnancy, maternal plasma CRH levels begin to rise in the second trimester with a dramatic increase in CRH levels during the 5-6 weeks preceding the onset of labor. This rise in maternal plasma CRH is parallel to the rise of placental CRH mRNA which has been reported to occur with gestational maturation. Mechanisms underlying the control of CRH secretion by the placenta have not yet been determined. In twin gestation, increased fetal-placental mass has been shown to be associated with elevated maternal levels of several placental hormones as compared to singleton gestation. We measured maternal plasma CRH in both twin and singleton gestation to investigate whether the larger size of the fetal-placental unit in twin gestation is associated with elevated maternal CRH levels. Seventy-six serial venous blood samples were collected from 20 women with twin gestation and 40 samples were obtained from 27 women with uncomplicated singleton gestation. Gestational age was determined by history of a known last menstrual period and first trimester clinical examination and confirmed by ultrasound examination. CRH was extracted from 1-2 ml plasma with SEP-Pak C18 cartridges and eluted with triethylamine-formic-acid propranolol. CRH was measured by radioimmunoassay (RIA) with human CRH standard and antiserum to human CRH raised in our laboratory. Mean CRH levels were calculated for four week intervals. In both singleton and twin gestation, the maternal plasma CRH levels increased with advancing gestational age. After 29 weeks of gestation, maternal plasma CRH levels in twin gestation were significantly higher than those in singleton gestation (p less than 0.01). At 37 to 40 weeks of gestation, mean maternal CRH was 1167 +/- 237 pg/ml in singleton gestation as compared to 6927 +/- 1725 pg/ml in twin gestation (p less than 0.05). In addition, the rapid rise in plasma CRH levels which occurs near term in singleton gestation, occurred earlier in twin gestation. This early rise in maternal CRH levels persisted when the data from twin pregnancies complicated by preterm labor were removed from the analysis.(ABSTRACT TRUNCATED AT 250 WORDS)