Maternal zinc and cord blood zinc, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels in small-for-gestational-age newborns

PURPOSE: To determine the relationship between maternal serum zinc (Zn) levels and birth weight of the offspring and their correlation with cord blood Zn, insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) levels. METHOD: 22 term small-for-gestational-age (SGA) and 34 term appropriate-for-gestational-age (AGA) infants and their mothers were included. Maternal and cord blood Zn levels and cord blood IGF-1 and IGFBP-3 levels were measured. RESULTS: Eighteen percent of mothers had Zn deficiency (< 75 mcg/dl). No significant difference between IGF-1 and IGFBP-3 levels and birth weight of infants of the mothers with and without Zn deficiency was found. Maternal and neonatal Zn levels correlated (r = 0.38, p < 0.01). Mean IGF-1 and IGFBP-3 levels were significantly lower in the SGA group compared to the AGA group (42.3 +/- 16.8 ng/ml, 1.2 +/- 0.2 mcg/ml, and 62.4 +/- 22.7 ng/ml, 1.5 +/- 0.4 mcg/ml, p < 0.001). A correlation was found between birth weight, IGF-1 and IGFBP-3 levels, and weight gain of the mother during pregnancy (p < 0.01). CONCLUSIONS: Zn deficiency was not observed to be a risk factor for low birth weight. The significant difference between the SGA and AGA babies' IGF-1 and IGFBP-3 levels emphasizes function of the IGF system in intrauterine growth.     

Hemoglobin, altitude and birth weight: does maternal anemia during pregnancy influence fetal growth?

OBJECTIVE: To investigate the relationship between maternal hemoglobin concentration, altitude and birth weight. STUDY DESIGN: Birth weights in 235 term pregnancies were investigated for their dependence on maternal hemoglobin concentration after other maternal and pregnancy-specific influences on fetal weight were taken into account. The additional predictive value of hemoglobin concentration on birth weight was assessed using multiple regression. Using published data, the relationship of hemoglobin concentration to altitude was determined, as was the effect of increasing altitude on birth weight. The quantitative effect of hemoglobin concentration on birth weight was correlated with the effect of altitude on hemoglobin concentration to assess whether this could account for the known decrease in birth weight with increasing altitude. RESULTS: Birth weights ranged from 2,220 to 4,850 g (mean, 3,505+/-443), and hemoglobin concentrations ranged from 9.3 to 13.5 g/dL (mean, 11.6+/-0.8). Apart from other known predictive variables, the variation in maternal hemoglobin concentrations at constant altitude independently explained 2.6% of the variance in birth weight (r=-.18, P=.003). Term birth weight was reduced by 89 g for each 1.0 g/dL increase in hemoglobin concentration (P<.01). For every 1,000-m increase in altitude, hemoglobin concentration increased by 1.52 g/dL and birth weight decreased by 117 g. CONCLUSION: Birth weight correlates negatively with maternal hemoglobin concentration. This is consistent with the well-known effect of high-altitude exposure during pregnancy, which increases both hematocrit and blood viscosity and lowers birth weight. The quantitative effect on birth weight of increasing maternal hemoglobin concentration at constant altitude is within 13% of the change in birth weight that can be attributed to the change in hemoglobin concentration associated with increases in altitude.     

Zinc and birth weight in uncomplicated pregnancies

The relationship between zinc status and birth weight in uncomplicated pregnancies was studied in 59 nulliparous and 27 multiparous Chinese women with singleton pregnancies, delivered at term. Maternal and umbilical cord blood, maternal pubic hair and a segment of the umbilical cord were collected at delivery for analysis. The zinc concentration was significantly higher (p less than 0.0001) in the plasma of newborn infants (13.9 +/- 2.8 mumol/l) than in maternal plasma (9.3 +/- 2.2 mumol/l), while the converse was found in tissue (60.8 +/- 17.0 vs 208.1 +/- 96.2 micrograms/g, p less than 0.0001). There was no significant correlation between birth weight and either maternal or newborn plasma or tissue zinc concentrations. Parity had no significant effect on maternal or newborn zinc concentrations in tissue and plasma.     

Maternal weight gain rate in the second trimester are associated with birth weight and length of gestation

BACKGROUND: Low total weight gain during pregnancy has been widely accepted as a valid risk factor for small-for-gestational-age infants and pre-term births. However, it is not obvious in which trimester the weight gain rate most affects birth weight and length of gestation. METHOD: Using logistic regression analysis and Pearson's correlation coefficient test, data from 472 women who had vaginally delivered an infant at term without any complications were analyzed retrospectively. RESULTS: Pre-pregnancy underweight and low total maternal weight gain were significant independent predictors of small-for-gestational-age infants and shortened gestations. Pre-pregnancy weight was significantly related to the birth weight and length of gestation (r = 0.18, p < 0.0001; r = 0.10, p = 0.04, respectively), and total weight gain was also significantly related to those (r = 0.17, p = 0.0003; r = 0.11, p = 0.03, respectively). Significant correlations between maternal weight gain rate in the second trimester and the birth weight and length of gestation were found (r = 0.32, p = 0.005; r = 0.40, p = 0.0003, respectively), while such correlations were not found in the first or third trimester. CONCLUSION: The most sensitive period of maternal weight gain for the birth weight and length of gestation was the second trimester.     

Hemodynamic changes in underweight pregnant women.

Twelve normal-weight and 12 underweight women were compared to test whether fetal growth retardation in underweight gravidas is related to inadequate maternal hemodynamic adjustments. Plasma volume (+/- standard error) was 3227 +/- 103 mL in normal-weight and 2731 +/- 84 mL in underweight women (P less than .002). Cardiac output was 6340 +/- 167 mL/minute in controls and 5689 +/- 213 mL/minute in underweight women (P less than .03). Total peripheral vascular resistance was lower in controls than in underweight subjects (1025 +/- 31 versus 1198 +/- 58 dyne/second/cm5). Mean birth weight was 2837 +/- 125 g in underweight women and 3362 +/- 106 g in controls (P less than .005). Similarly, placental weight was reduced in the underweight group. All infants delivered by control mothers had a normal birth weight, whereas six infants from underweight gravidas were growth-retarded. In all cases combined, maternal plasma volume correlated significantly with both birth weight (r = 0.6, P less than .002) and placental weight (r = 0.56, P less than .01); total peripheral vascular resistance also correlated significantly and inversely with newborn weight and placental weight. Cardiac output correlated only with placental weight (r = 0.54, P less than .02). These results are consistent with the hypothesis that underweight mothers are at higher risk of fetal growth retardation because of a smaller plasma volume and lower cardiac output.     

Inherited thrombophilias are not increased in "idiopathic" small-for-gestational-age pregnancies

OBJECTIVE: The purpose of this study was to determine (1). whether the inherited thrombophilias (the factor V Leiden and prothrombin gene mutations and the methylenetetrahydrofolate reductase [C677T] polymorphism) are increased in women with "idiopathic" (normotensive) small-for-gestational-age pregnancies and/or in their babies and (2). whether fetal carriage of a thrombophilia is associated with abnormal umbilical Doppler studies. STUDY DESIGN: This was a case-controlled study of normotensive women who were delivered of a singleton small-for-gestational-age baby (birth weight, <10th percentile adjusted for sex) with no clinical evidence of chromosomal or congenital abnormality. Control subjects were healthy women who were delivered of appropriate-for-gestational-age babies. RESULTS: One hundred forty-five women with small-for-gestational-age pregnancies and 290 control subjects were recruited. Small-for-gestational-age babies were born at an earlier gestational age (38 +/- 3.0 weeks) and with a lower birth weight (2373 +/- 521 g) than control babies (39.7 +/- 1.3 weeks and 3606 +/- 423 g, P <.01). There were no differences in the rates of factor V Leiden (2.8% vs 3.8%; relative risk, 0.79; 95% CI, 0.34-1.85), prothrombin gene mutation (2.8% vs 3.1%; relative risk, 0.92; 95% CI, 0.40-2.09), and methylenetetrahydrofolate reductase C677T polymorphism (13% vs 9%; relative risk, 1.27; 95% CI, 0.87-1.84) between mothers with small-for-gestational-age babies and control subjects, respectively. Inherited thrombophilias were not increased in small-for-gestational-age babies compared with control babies. Of small-for-gestational-age babies with abnormal umbilical artery Doppler studies (n = 25), 21% had a thrombophilia compared with 11% with normal umbilical artery Doppler studies (n = 68; relative risk, 1.75; 95% CI, 0.81-3.81). CONCLUSION: The rates of these inherited thrombophilias are not increased in normotensive women with small-for-gestational-age pregnancies. Further studies are required to determine whether thrombophilias are increased in small-for-gestational-age babies with abnormal umbilical Doppler study results.     

Plasma adrenomedullin levels in pregnancies with appropriate for gestational age and small for gestational age infants.

AIMS: To evaluate whether maternal and fetal plasma adrenomedullin levels in pregnancies with small for gestational age (SGA) infants are different from those in pregnancies with appropriate for gestational age (AGA) infants. METHODS: Maternal and fetal circulating adrenomedullin levels were compared between 62 pregnancies with AGA (43 delivered vaginally and 19 delivered by elective cesarean section) and 28 pregnancies with SGA (20 delivered vaginally and 8 delivered by elective cesarean section) at birth. Plasma adrenomedullin levels were measured from maternal and cord venous blood samples using a radioimmunoassay. Umbilical artery blood pH was also measured. RESULTS: There were no significant differences for maternal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. There were also no significant differences for fetal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. In the AGA group delivered vaginally, fetal mature/total adrenomedullin ratio (mean +/- standard error, 16.6 +/- 0.7%) was significantly higher than the maternal ratio (13.8 +/- 0.6%) (p < 0.05). In the SGA group delivered vaginally, fetal mature/total adrenomedullin ratio (18.5 +/- 1.0%) was also significantly higher than the maternal ratio (14.5 +/- 0.6%) (p < 0.05). There was no significant difference in umbilical artery blood pH among the groups. CONCLUSIONS: These results suggest that maternal and fetal plasma circulating adrenomedullin levels may play a role in maternal and fetal cardiovascular adaptation during delivery in pregnancies with both AGA and SGA infants.     

Antenatal phenobarbital and bilirubin metabolism in the very low birth weight infant

Prior studies in term infants have suggested that in utero phenobarbital exposure may accelerate bilirubin metabolism by stimulating hepatocyte glucuronyl transferase activity. This report reviews our experience with maternal phenobarbital therapy and fetal bilirubin conjugation in the very premature fetus. Mothers with arrested premature labor between 26 and 33 weeks' gestation were randomly assigned to receive oral phenobarbital (90 mg daily) or not. Infants in the two groups were similar in race, birth weight, and gestational age. Conjugated bilirubin levels at birth were significantly higher for infants receiving several days of phenobarbital in utero than no therapy (0.31 +/- 0.03 vs 0.16 +/- 0.01 mg dl, p less than 0.01). A smaller portion of infants exposed to phenobarbital in utero required phototherapy (10/23, 43% vs 24/29, 83%, p less than 0.01), which was also more likely to be delayed beyond 48 hours after delivery. Antenatal phenobarbital enhances bilirubin conjugation before delivery of a very low birth weight infant.     

The association between abnormal glucose tolerance (hyperglycemia and hypoglycemia) and estriol excretion in pregnancy.

In 2,000 consecutive patients having glucose tolerance tests in pregnancy hyperglycemia (greater than or equal to ninety-fifth percentile) was associated with increased placental weight (p less than 0.01) but not with increased fetal birth weight. Patients with hypoglycemia (less than or equal to fifth percentile) were more likely to have small-for-dates babies (p less than 0.01). Perinatal death was related to maternal glucose tolerance, being reduced from 1.3% in the total series to 0.6% when normoglycemia was present (p less than 0.05); it was significantly increased in the presence of maternal hyperglycemia (p less than 0.001) and hypoglycemia (p less than 0.01). A combination of abnormal glucose tolerance and subnormal estriol excretion detected pregnancies with significantly higher incidences of fetal and placental growth retardation, major fetal malformations, and perinatal deaths. Moreover, the combination of normoglycemia and normal estriol excretion (62.3% of patients) was associated with a very favorable pregnancy outcome (0.4% perinatal death rate). Hypoglycemia was at least as significant as hyperglycemia in terms of unfavorable pregnancy outcome, especially when associated with subnormal estriol excretion.     

Poor maternal weight gain between 28 and 32 weeks gestation may predict small-for-gestational-age infants

In a retrospective analysis of 158 women considered to have had normal, low-risk pregnancies, 30 gave birth to infants with a birthweight less than the 10th centile for gestation. These 30 women had a significantly poorer mean increase in weight (0.99 kg) between 28 and 32 weeks gestation than the other 128 women (1.95 kg) who gave birth to infants with birthweights above the 10th centile for gestation. There was no statistically significant difference in booking weight, overall weight gain or other variables associated with low birthweight between the two groups of women which suggests that poor maternal weight gain specifically between 28 and 32 weeks gestation may predict small-for-gestational-age infants.     

Birth weight standards for triplets under modern obstetric care in the United States, 1984-1989

Birth data were reviewed on 3321 live-born infants from 1138 triplet pregnancies delivered in the United States between 1984-1989. The three major etiologies for the multiple gestations were fertility drugs (50%), spontaneous (38%), and in vitro methods (9%). The average length of gestation was 33.8 weeks and the mean birth weight was 1911 g. Neonatal birth weight curves for triplet infants born alive in the third trimester were plotted. From 26-35 weeks, the average triplet newborn has a weight corresponding to approximately the 30th percentile level compared with singletons. After 35 weeks, triplet birth weights fall progressively behind those of singletons, reaching the tenth percentile at 38 weeks. Multiple epidemiologic factors were analyzed to determine their effect upon neonatal birth weight and length of gestation. Factors predicting higher than average birth weight included male sex, increasing maternal age, increasing maternal height and weight, maternal weight gain, and maternal parity. The length of gestation was found to correlate with maternal age, weight gain, and parity. No significant association between fertility method and gestational age or weight could be identified. This large data base provides the first comprehensive percentile birth weight rankings for modernly managed triplet gestations in the United States population. A regression equation is presented which accurately predicts mean triplet birth weight in the third trimester and which suggests that a nearly linear weight gain of approximately 150 g per week per fetus should be expected in this period.     

Placental function test, clinical and biochemical parameters in diabetic pregnancy complicated by retinopathy

The pregnancy in specific-beta 1-glycoprotein (SP1) has been characterized as a beta 1 electrophoretic mobile glycoprotein with a molecular weight of 90,000 daltons. SP1 is known to be synthesized by the trophoblast. The measurement of this protein has been shown to be useful as a placental function test. At present, we have compared maternal SP1 serum levels in diabetic pregnancies between White classes A to D on the one hand and R, F on the other. A total of 37 uncomplicated pregnancies in healthy women and 32 of insulin-dependent pregnant diabetic women were examined between completed gestational weeks 8 and 41. In the diabetic group there were eleven women with diabetic retinopathy. Maternal SP1 serum levels were estimated by single radial immunodiffusion using a monospecific antiserum. In the results were integrated maternal and neonatal data such as glycemic control, glycosylated hemoglobin and insulin requirements. In each group there was a significant rise in maternal SP1 serum values in the second and the third trimester, when compared with values in the first trimester (p less than 0.01). Between the 34th and the 37th gestational week we found significantly lower SP1 values (p less than 0.05) in the retinopathic group (104.2 +/- 28.7 mg/l) in comparison with the control group (149.9 +/- 61.0 mg/l) and non-retinopathic group (139.1 +/- 41.7 mg/l).     

Apolipoprotein AI levels in cord blood]

Lipid is known to increase during pregnancy but the factors responsible for the change have not been established. In addition, the lipid concentration in preeclamptic pregnancy is significantly higher than in normal pregnancy. The apolipoproteins are an important determinant of metabolism and the structure of plasma lipoproteins. The 26 healthy pregnant women, the levels of cord apolipoprotein AI were determined by TIA methods. The cord and plasma apolipoprotein AI were 76.12 +/- 20.04 mg/dl (n = 26, mean +/- S.D.) and 190.50 +/- 18.84 mg/dl, respectively. Cord apolipoprotein levels correlated to maternal age (r = -0.12, p less than 0.05), maternal weight (r = -0.11, p less than 0.01), the gestational week (r = +0.42, p less than 0.01), infant weight (r = -0.01, p less than 0.05), placental weight (r = -0.03, p less than 0.05), and diastotlic blood pressure (r = +0.06, p less than 0.05). These data suggest that the measurement of cord apolipoprotein AI may be a useful factor in evaluating preeclamptic pregnancy.     

Doppler velocimetry determined redistribution of fetal blood flow: Correlation with growth restriction in diamniotic monochorionic and dizygotic twins

OBJECTIVE: Our purpose was to study fetal growth and blood flow distribution in diamniotic monochorionic compared with dizygotic (diamniotic dichorionic) twins by use of Doppler velocimetry of the umbilical artery and middle cerebral artery. STUDY DESIGN: Study candidates were divided into group A, consisting of 33 pairs (66 fetuses) of diamniotic monochorionic twins, and group B, 50 pairs (100 fetuses) of diamniotic dichorionic twins. Diamniotic monochorionic placentation was confirmed by microscopic placental examination for group A. Diamniotic dichorionic placentation was ensured for group B by selecting only twins with different-sex pairs (dizygotic twins). Targeted ultrasonography with biometry was performed in each twin, and Doppler recordings of the umbilical artery and middle cerebral artery were obtained. Waveforms were analyzed and the systolic/diastolic ratio, the resistance index, and a measure of blood flow redistribution (brain-sparing effect), the cerebral/placental ratio, was calculated for each fetus. Growth status at birth was assessed by the number of small-for-gestational-age infants (≤10th percentile), low-birth-weight infants (≤25th percentile), and percent of growth discordance between twins. Intertwin differences were assessed by Δ values (value of larger twin minus value of smaller twin). RESULTS: Diamniotic monochorionic compared with dizygotic twins demonstrated a significantly greater probability of blood flow redistribution. For the study population as a whole, the brain-sparing effect was noted in 67% of small-for-gestational-age babies and only 7% of non-small-for-gestational-age infants (p ≤ 0.001). For the diamniotic monochorionic pregnancies blood flow redistribution occurred in 6 of 10 small-for-gestational-age infants (60%) and 6 of 46 non-small-for-gestational-age infants (13%). In the diamniotic monochorionic group small-for-gestational-age compared with non-small-for-gestational-age infants were more likely to show blood flow redistribution, which was the result of significantly decreased resistance in the middle cerebral artery and significantly increased resistance in the umbilical artery. Small-for-gestational-age infants (≤10th percentile) occurred much less frequently in the dizygotic group. Two of two small-for-gestational-age infants in the dizygotic group showed blood flow redistribution. Although the extremes of birth weight were more common in the diamniotic monochorionic group, both groups had relatively large numbers of small babies with birth weights in the lower 25th percentile (50.0% for diamniotic monochorionic and 44.0% for dizygotic twins, not significant). However, 42.3% (11/26) of diamniotic monochorionic twins who were in the low-birth-weight group showed blood flow redistribution compared with only 3.3% (1/30) whose birth weights were ≥25th percentile (p ≤ 0.001). In the dizygotic twins 10% of lower-birth-weight infants redistributed blood flow compared with 1% in the higher-birth-weight group, a nonsignificant difference. Diamniotic monochorionic compared with dizygotic twins were delivered earlier (32.9 weeks vs 34.8 weeks, p ≤ 0.001), were smaller (1832 gm vs 2304 gm, p ≤ 0.001), showed higher birth weight discordance (29.8% vs 14%, p ≤ 0.05), and had greater numbers (19.7% vs 2.3%, p ≤ 0.01) of infants at ≤10th percentile birth weight. CONCLUSIONS: Diamniotic monochorionic twins from the lower-birth-weight groups more often show blood flow redistribution compared with dizygotic twins of similar low birth weights. Placental vascular connections and the attendant hemodynamic changes in the fetuses of diamniotic monochorionic twins probably account for this difference. Brain-sparing events occur commonly without clinical twin transfusion syndrome in this group. These findings have implications for management. (Am J Obstet Gynecol 1998;178:1359-67.)     

Dextrocardia in pregnancy: 20 years' experience

OBJECTIVE: To identify all pregnancies complicated by maternal dextrocardia and report the obstetric performance in these patients. STUDY DESIGN: A retrospective review of all deliveries between May 1984 and December 2004 at Prince of Wales Hospital, Chinese University of Hong Kong. Maternal demographic data as well as information on the antenatal course and delivery outcome were abstracted from the maternal records. Neonatal record review yielded information on the gestational age at delivery, birth weight, Apgar scores, sex and neonatal conditions after delivery. RESULTS: Fifteen singleton pregnancies in 9 patients with dextrocardia were identified. There were 6 pregnancies in 3 patients with situs inversus and 9 pregnancies in 6 patients with isolated dextrocardia. There were no apparent antenatal complications. None of the patients developed any cardiac symptoms antenatally. All the infants had a 5-minute Apgar score > 7. Four small-for-gestational-age (SGA) infants, defined after correcting for parity, gestational age, maternal height and maternal entry weight, occurred in patients with situs inversus. This is significantly different from the 10% expected (p < 0.002). No SGA infants were born to patients with isolated dextrocardia. CONCLUSION: Pregnancies complicated by maternal isolated dextrocardia did not have any detrimental effect on the disease or vice versa. However, SGA infants should be watched in patients with situs inversus.     

Significance of raised maternal serum alpha-fetoprotein in singleton pregnancies with normally formed fetuses

One hundred eighty-six pregnancies with elevated maternal serum alpha-fetoprotein (AFP) between 16 and 20 weeks' gestation, but with normally formed single fetuses, were analyzed retrospectively. In comparison with matched control subjects, there was an increased incidence of low birth weight, preterm delivery, intrauterine growth retardation, and other clinical complications, especially when maternal serum AFP was abnormally high on more than one occasion. These findings could not be explained by the occurrence of threatened abortion or the performance of amniocentesis. It is suggested that where maternal serum AFP screening for fetal neural tube defects is already established as a cost-effective routine procedure, the additional recognition of some pregnancies at very high risk of other, perinatal complications is of practical value. However, maternal serum AFP testing in the second trimester cannot be recommended as a cost-effective screening method for detecting low birth weight infants, having a sensitivity in this series of only 11%. Many (33%) of the low birth weight infants detected in this way were very small (birth weights less than 1.5 kg); 73% of the predicted preterm births were very premature (before 34 weeks of gestation), and 72% of the identified growth-retarded infants were severely effected (weighing less than the fifth percentile for gestational age).     

Poor maternal weight gain between 28 and 32 weeks gestation may predict small-for-gestational-age infants

Summary. In a retrospective analysis of 158 women considered to have had normal, low-risk pregnancies, 30 gave birth to infants with a birth-weight less than the 10th centile for gestation. These 30 women had a significantly poorer mean increase in weight (0·99 kg) between 28 and 32 weeks gestation than the other 128 women (1·95 kg) who gave birth to infants with birthweights above the 10th centile for gestation. There was no statistically significant difference in booking weight, overall weight gain or other variables associated with low birthweight between the two groups of women which suggests that poor maternal weight gain specifically between 28 and 32 weeks gestation may predict small-for-gestational-age infants.     

Placental weight in diabetic pregnancies

The placenta from 30 women with diabetes mellitus were examined and weighed at delivery. Nineteen of these were from women with overt and eleven from women with gestational diabetes. Eleven placentae from normal pregnancies served as controls. There was no difference between the mean +/- s.d. placental weight for the diabetic group and the control group (609 +/- 148 versus 591 +/- 93 g, NS). The mean placental weight ratios for the diabetic group and the control group were also similar (0.98 +/- 0.23 versus 0.89 +/- 0.15, NS). Moreover, there was no difference between the weights and weight ratios of placentae from women with overt (622 +/- 173 g, 1.02 +/- 0.27) and those with gestational diabetes (586 +/- 90 g, versus 0.90 +/- 0.13). Placental weights correlated with birthweights (r = 0.70, P less than 0.01) and with skinfold thickness measurements fo the infants (r = 0.40, P less than 0.05), but neither with gestational ages (r = 0.15, NS) nor with maternal glycosylated haemoglobin levels in the third trimester (r = 0.24, NS). Among the women with overt diabetes, placental weights were greater in those in White's class B and C than those in class D and R (689 +/- 143 versus 530 +/- 177 g; P less than 0.05). In general, placentae from well controlled diabetic patients were not heavier than those from normal pregnant women, although there was an increase in placental weight in White's class B and C, as compared with those in class D and R.     

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.     

Serum leptin concentration in cord blood: relationship to birth weight and gender in pregnancies complicated by pre-eclampsia.

The aim of the study was to investigate cord blood leptin concentrations and their relationship to birth weight and gender in term pregnancies complicated by pre-eclampsia. Cord blood samples were obtained from 52 women, identified as having pre-eclampsia, and their newborns (31 males and 21 females) immediately after birth. Specimens were analyzed using a human leptin 125I radioimmunoassay. The relationship between leptin and anthropometrics was assessed by Spearman correlation. Differences in cord blood leptin levels between male and female infants were tested with the Mann-Whitney U test. The correlation between leptin and gender was computed using the product-moment-biseral correlation analysis for continuous and dichotomous variables. The multiple logistic regression analysis examined influences of sex, birth length, birth weight, birth weight/birth length ratio, ponderal index and maternal leptin as covariates on the fetal cord leptin level. Fetal leptin correlated positively with birth weight, length and weight/length ratio, in the total group and in the male subgroup and additionally with ponderal index in the female subgroup. Cord blood leptin concentrations in female newborns were significantly higher than in male newborns (p = 0.015), and concentrations correlated with gender (r = -0.315; p = 0.023). Multiple logistic regression analysis revealed four potential independent factors influencing fetal cord leptin: gender, birth weight, birth weight/birth length ratio and maternal leptin. In conclusion, cord leptin concentrations in pregnancies complicated by pre-eclampsia correlate positively with birth weight and gender. Leptin concentrations in female newborns are higher compared to male newborns.