Human fetal-placental weight ratio in normal singleton near-term pregnancies.

OBJECTIVE: To determine the fetal-placental weight ratio in normal near-term singleton pregnancies. PATIENTS AND METHODS: 431 consecutive singleton near-term live deliveries following uncomplicated pregnancies were included in a prospective study. Mean maternal age was 28.6 years (range 17-50), mean parity was 2.9 (range 1-16). Mean gestation age at delivery was 39.7 weeks (range 33-42). RESULTS: Mean newborn weight was 3,382.1 +/- 486.7 g (range 2,180-4,810). Mean placental weight was 613.0 +/- 123.8 g (range 319-1,266). Mean fetal-placental weight ratio was 5.6 +/- 0.96 (range 2.9-10.6) with kurtosis of 3.6 and skewness of 1.05. The ratio did not differ significantly between male (n = 253) and female (n = 176) infants, 5.7 +/- 0.89 and 5.6 +/- 1.04, respectively. There was a progressive increase in the fetal-placental weight ratio with gestational age (r = 0.87): from 5.3 +/- 0.90 at 33-36 weeks to 5.9 +/- 1.06 at the 41st week and 5.7 +/- 0.71 at the 42nd week (p < 0.05) and with birth weight distribution (r = 0.85) from 5.0 +/- 1. 06 in newborns weighing 2,000-2,499 g to 5.9 +/- 0.94 in newborns weighing >4,000 g (p < 0.05). There was a positive relationship between the fetal-placental weight ratio in teenage and elder parturients (r = 0.98): 5.2 +/- 0.98 (age 17-19), 5.7 +/- 0.88 (age 20-29), 5.6 +/- 1.08 (age 30-39), and 5.7 +/- 0.96 (age 41-50) (p < 0.05). The most contributing variable was birth weight. CONCLUSIONS: The fetal-placental weight ratio tends to be low in teenage women, early near-term gestational age, and low fetal weight. There was a progressive increase in the fetal-placental weight ratio with gestational age and with birth weight distribution.     

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.     

Increased fetal adiposity: a very sensitive marker of abnormal in utero development

OBJECTIVE: Because offspring of women with gestational diabetes mellitus have an increased risk of obesity and diabetes mellitus as young adults, our purpose was to characterize body composition at birth in infants of women with gestational diabetes mellitus and normal glucose tolerance. STUDY DESIGN: One hundred ninety-five infants of women with gestational diabetes mellitus and 220 infants of women with normal glucose tolerance had anthropometric measurements and total body electrical conductivity body composition evaluations at birth. Parental demographic, anthropometric, medical and family history data, and diagnostic glucose values were used to develop a stepwise regression model that related to fetal growth and body composition. RESULTS: There was no significant difference in birth weight (gestational diabetes mellitus [3398+/-550 g] vs normal glucose tolerance [3337+/-549 g], P=.26) or fat-free mass (gestational diabetes mellitus [2962+/-405 g] vs normal glucose tolerance [2975+/-408 g], P=.74) between groups. However, infants of women with gestational diabetes mellitus had significantly greater skinfold measures (P=.0001) and fat mass (gestational diabetes mellitus [436+/-206 g] vs normal glucose tolerance [362+/-198 g], P=.0002) compared with infants of women with normal glucose tolerance. In the gestational diabetes mellitus group, although gestational age had the strongest correlation with birth weight and fat-free mass, fasting glucose level had the strongest correlation with neonatal adiposity. CONCLUSION: Infants of women with gestational diabetes mellitus, even when they are average weight for gestational age, have increased body fat compared with infants of women with normal glucose tolerance. Maternal fasting glucose level was the strongest predictor of fat mass in infants of women with gestational diabetes mellitus. This increase in body fat may be a significant risk factor for obesity in early childhood and possibly in later life.     

胎盘细胞凋亡与胎儿生长受限关系的研究

目的　探讨胎盘细胞调亡与胎儿生长受限 (FGR)发生的关系。方法　应用透射电镜和DNA缺口末端标记法检测 18例FGR患者 (FGR组 )及 14例正常妊娠妇女 (正常妊娠组 )的胎盘细胞凋亡情况。同时观察两组的胎盘重量及新生儿平均出生体重。结果　FGR组胎盘凋亡细胞核比率为12 1‰ ,电镜下凋亡细胞核呈明显致密状 ,染色质结块 ,胎盘平均重量为 (2 3 6± 2 4)g ,新生儿平均出生体重为 (2 0 71± 42 8)g;正常妊娠组胎盘凋亡细胞核比率为 7 3‰ ,胎盘平均重量为 (3 5 4± 63 )g ,新生儿平均出生体重为 (3 411± 5 88)g。FGR组胎盘凋亡细胞核比率明显高于正常妊娠组 (P <0 0 5 )。结论　胎盘细胞凋亡增加与FGR的发生有关     

Impact of fetal reduction on the incidence of gestational diabetes.

OBJECTIVE: To estimate the rate of gestational diabetes in triplet pregnancies and to assess the impact of fetal reduction on the incidence of this complication. METHODS: One hundred eighty-eight consecutive triplet pregnancies referred to the Sheba Medical Center between 1994 and 1998 were included. One hundred three of these pregnancies continued as triplets, whereas 85 women elected to undergo fetal reduction to twins. The incidence of gestational diabetes (based on the criteria of Carpenter and Coustan) and other outcome variables were compared between the two groups. Student t-tests and chi(2) analysis were used as appropriate. RESULTS: Mean (+/-SD) maternal age was 29.2 +/- 4.8 in the triplet group and 29.3 +/- 4.1 in the reduction group. The groups had similar median parity (1.6 +/- 1.1 in the triplet group and 1.5 +/- 0.7 in the reduction group). The rate of gestational diabetes was significantly higher in the triplet group than in the reduction group (22.3% vs 5.8%). A lower birth weight (1764 +/- 448 g vs 2208 +/- 526 g) and an earlier gestational age at delivery (33.4 +/- 2.8 weeks vs 36.0 +/- 2.8 weeks) were observed in the triplet group compared with the reduction group. CONCLUSION: The number of fetuses in multifetal pregnancies influences the incidence of gestational diabetes. These findings support the hypothesis that an increase in placental mass and, thus, an increase in diabetogenic hormones play a role in the etiology of gestational diabetes.     

Foetal and placental weights in relation to maternal characteristics in gestational diabetes

An increased placental weight has been reported in pregnancies complicated with gestational diabetes (GDM). We have analysed foetal (F) and placental weight (P) and foetal length in 143 consecutive normal (N) and 132 GDM pregnancies in relation to type of treatment and to a number of maternal variables. All N pregnancies had a negative oral glucose challenge test at 24-28 weeks. GDM was diagnosed at 28-32 weeks by a 100-gm, 3-h oral glucose tolerance test (OGTT). Treatment was diet (D: n=82) or diet plus insulin (D+I: n=50) according to self-monitoring of blood glucose. A significant difference was observed between N and GDM pregnancies for maternal age (N=30.6+/-5.38 years; GDM=33.2+/-4.53 years; P< 0.001), pre-pregnancy weight (N=58.2+/-8.0 kg; GDM=63.0+/-12.9 kg; P< 0.001) and BMI (N= 21.9+/-2.63; GDM=24.4+/-4.71;P< 0.001). Foetal weight became significantly higher in the GDM group (N=3274.2+/-296.0 g; GDM=3287.1+/-474.1g; P< 0.05) once correction was made for the significant difference in gestational age between the two groups (N=39.4+/-1.17 weeks; GDM=38.8+/-1.39 weeks; P< 0.001). Significantly higher placental weights (N=561.87+/-91.0 g; GDM=592.2+/-115.8 g;P< 0.01) and significantly lower F/P weight ratios were found in GDM pregnancies (N=5.96+/-1.02; GDM=5.69+/-1.13; P< 0.05).In GDM pregnancies a significantly negative correlation was found between the OGTT response and weights of foetus and placentae at delivery, suggesting that both foetal and placental growth are affected by maternal insulin resistance.     

Decreased plasma levels of metastin in early pregnancy are associated with small for gestational age neonates

OBJECTIVE: To investigate whether pregnancies with small for gestational age (SGA) neonates, defined as customized birth weight below the 10th centile, are associated with altered levels of metastin in maternal plasma in the first trimester. STUDY DESIGN: Maternal blood was obtained between 8 and 14 weeks of pregnancy. Levels of metastin were measured in pregnancies with (n = 31) or without SGA-neonates (n = 31), matched for gestational age at venipuncture. Measurement of beta-hCG was included to study the influence of gestational age and placental volume on plasma levels of the measured markers. RESULTS: Metastin was significantly lower in SGA-pregnancies compared to an equal number of matched uneventful pregnancies (metastin: 1376 +/- 1317 pmol/L vs 2035 +/- 1260 pmol/L, p = 0.035; mean +/- standard deviation). beta-hCG levels were not different. CONCLUSION: Metastin is significantly lower in maternal plasma in the first trimester, in pregnancies with SGA-neonates. It might therefore be used in combination with other markers for risk estimation of growth impairment in the first trimester.     

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.     

Maternal and fetal consequences of increased gestational weight gain in women of normal prepregnant weight

OBJECTIVE: To study the effects of increased gestational weight gain in women of normal prepregnant weight. PATIENTS AND METHODS: We compared 174 patients gaining more than 18 kg to 174 patients gaining between 9 and 15 kg. Body mass index was normal for every woman included in the study. RESULTS: Weight gain > or =18 kg was associated with increased risk of vascular complications (5.2% vs. 1.1%, P < 0.05) but not with increased risk of mellitus diabetes (5.2% vs. 4.0%, NS). Weight gain > or =18 kg prolonged labor length (414.4 +/- 147 min vs. 376.5 +/- 166.4 min, P < 0.05) and increased the rate of cesarean section (19.5% vs. 10.3%, P < 0.05). Neonatal outcome was similar in both groups, mean birth weight was greater (3413.6 +/- 427.0 g vs. 3163.4 +/- 495.1 g, P < 0.05) and the frequency of infants weighing more than 4000 g at birth was increased (8.0% vs. 4.0%, P < 0.05) among women gaining more than 18 kg. CONCLUSION: Excess weight gain in pregnancy affects gestational and delivery outcomes and results in higher frequency of fetal macrosomia. These results confirm recommendations on weight gain in pregnancy as guidelines for pregnant women.     

Maternal hemoglobin F levels may have an adverse effect on neonatal birth weight in pregnancies with sickle cell disease

A total of 26 patients with sickle cell disease were followed up through 32 pregnancies. There was no correlation between days in hospital or number of painful crises and either birth weight or birth weight percentile. The number of dense irreversibly sickled and least deformable cells was negatively correlated with birth weight percentile (r = -0.63, p less than 0.01). Patients' initial hemoglobin levels were positively correlated with birth weight percentile (r = 0.52, p less than 0.004). Hemoglobin F, on the other hand, was significantly inversely correlated with birth weight percentile. Nine pregnancies with small-for-gestational-age infants had an average hemoglobin level of 9.1% +/- 4.5%. In contrast, patients who were delivered of appropriate-for-gestational-age infants (23 pregnancies) had an average hemoglobin F level of 3.6% +/- 2.9% (p less than 0.01). We conclude that total hemoglobin levels and dense cells are correlated with birth weight percentile; moreover, the higher the maternal hemoglobin F levels the higher the risk of small-for-gestational-age infants. We speculate that although high hemoglobin levels may be beneficial to the fetus, high maternal hemoglobin F levels could increase the desaturation of non-F cells and induce placental obstruction.     

Placental lesions and maternal hemoglobin levels. A comparative investigation

A high maternal hemoglobin level during pregnancy has been correlated to a low birth weight and a low placental weight, but has not been investigated in relation to placental factors. In 330 consecutive deliveries, placental lesions, birth weight and placental weight were studied in a multiple regression analysis in relation to maternal hemoglobin concentration, taking into consideration possible confounding factors such as smoking, hypertensive disorders, weight gain, primiparity, gestational age and sex. A high maternal hemoglobin concentration (greater than 130 g/l) was correlated with a low birth weight, acute infarcts and syncytial knots. Intervillous thrombosis was more common in non-smokers and multiparous women, increasing in incidence as gestational age advanced. Infarcts and microscopic perivillous fibrin were correlated with hypertension. Microscopic perivillous fibrin was slightly associated with a high hemoglobin level (greater than 130 g/l) in a bivariate analysis. These findings may indicate that a high maternal hemoglobin level impairs the uteroplacental circulation.     

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.     

Placental isoferritin measured by a specific monoclonal antibody as a predictive marker for preterm contraction outcome

The serum levels of placental isoferritin and normal ferritin in 25 women with preterm contractions (mean +/- SE gestational age 28.8 +/- 4.7 weeks) were compared with those in 14 control women with uncomplicated pregnancies (29.1 +/- 7.3 weeks). The serum concentration of placental isoferritin in women with preterm contractions (15.3 +/- 6.2 U/mL) was significantly lower than that in normal pregnant women (87.6 +/- 22.6 U/mL) (P = .005). The level of normal ferritin in women with preterm contractions (30.6 +/- 4.16 ng/ml) was lower than that in women with normal pregnancies (67 +/- 9.6 ng/mL) (P = .01); however, both were within the normal range. Serum placental isoferritin levels correlated with pregnancy outcome; low placental isoferritin (up to 10 U/mL) was a sensitive (71.5%) indicator of preterm labor. Low placental isoferritin had a positive predictive value of 59% and a negative predictive value of 71%. These results suggest that placental isoferritin may serve as a predictive marker for the prognosis of preterm contractions.     

Subsequent pregnancy following labor of a very-low-birth-weight infant

During a period of 5 years (1978-1982), 55 mothers with an average age of 27.5 +/- 5.4 years, delivered 59 infants, weighing less than 1500 g. These infants had a mean birth weight of 1160.5 +/- 263 g and a mean gestational age of 28.7 +/- 2.25 weeks (range 25-32 weeks). Subsequently 47 (79.6%) survived and 12 (20.4%) died. There was a statistical difference of both mean gestational age and of mean gestational weight between survivors or infants with neonatal death. Twenty two of 29 mothers who subsequently became pregnant, gave birth to liveborn infants, who subsequently survived (four pregnancies terminated in induced abortion). Mean gestational age was 37 +/- 3 weeks (range 32-41 weeks) (P less than 0.001) and a mean birth weight was 2753.2 +/- 570 g (range 1620-3600 g) (P less than 0.001. All the 22 infants subsequently born weighed more than 1501 g, 7 (31.8%) infants weighed 1501-2500 g and 15 (68.2%) more than 2500 g. Similar data were obtained from a control group of 615 mothers (chosen at random) who delivered a normal infant at term, 202 subsequently became pregnant and 176 gave birth to a normal infant at term. Mean gestational age was 39.54 +/- 1.24 weeks (P less than 0.001) and mean birth weight was 3299.3 +/- 412 g (P less than 0.001). (In the control group 10 pregnancies terminated in induced abortions). The above data could be used in advising for future pregnancy outcome in regard to women with premature births.     

Perinatal morbidity and placental size in gestational impaired glucose tolerance.

OBJECTIVE: The clinical significance of large placentas in diabetic pregnancies is not known. A retrospective study was performed to determine whether a disproportionately large placenta, as represented by a high ratio of placental weight to birth weight (placental ratio), in pregnancies complicated by the World Health Organization category of impaired glucose tolerance (IGT), was associated with perinatal morbidity. METHODS: We categorized 1472 consecutive singleton pregnancies with gestational IGT as having a high placental ratio (> 0.2095 or mean plus one standard deviation of the value established for appropriate-for-gestational age infants from nondiabetic pregnancies in a previous study) or a normal ratio. Maternal characteristics and glycemic parameters, infant birth weight and neonatal complications, and placental weight were compared between these two groups. RESULTS: A high placental ratio was found in 400 (27.2%) pregnancies. This group had similar maternal anthropometric and glycemic parameters, except for a slightly higher prepregnancy body mass index and fasting glucose level in the oral glucose tolerance test. The high placental ratio was from increased placental weight rather than the decreased birth weight. The neonates had increased incidence of low 1-minute Apgar score, treatment for neonatal jaundice and infection, and respiratory complications. After adjusting for the effects of preterm birth and vaginal delivery, a high ratio was still associated with low Apgar score, respiratory complications, and treatment for infection. CONCLUSIONS: The placental ratio in pregnancies complicated by IGT was unrelated to maternal characteristics or glycemic status, but a high ratio was associated with increased perinatal morbidity.     

Implications of a high placental ratio in pregnancies with appropriate-for-gestational age neonates

OBJECTIVE: To determine the relationship between the placental weight to birth weight ratio (placental ratio) with maternal pre-pregnancy weight, gestational weight gain, and neonatal outcome in non-diabetic pregnancies resulting in appropriate-for-gestational age (AGA) infants. METHODS: A retrospective study was performed on 593 patients with singleton pregnancies, normal results in the 75-gram oral glucose tolerance test and who delivered AGA newborns within a 1-year period. The patients were categorized into high placental ratio (> mean +1 SD based on previous data, n = 113 or 19.1%) and normal ratio groups for the comparison of maternal and neonatal anthropometric parameters. RESULTS: The high placental ratio group had a higher pre-pregnancy weight, body mass index, placental weight, and incidence of low Apgar score, but decreased absolute and percentage gestational weight gain, gestational age, and birth weight. After controlling for pre-pregnancy weight and gestational age, only the correlation between placental weight and percent weight gain remained significant. CONCLUSION: Our finding suggests that a high placental ratio can identify AGA newborns who are disproportionately small relative to maternal size, and may reflect some form of fetal growth impairment.     

Placental nutrient transfer capacity and fetal growth

The objective of this study was to determine whether the ability of the human placenta to transfer glucose and fatty acids is related to normal fetal growth. The intrinsic nutrient transport capacity of the placenta was measured under standardized conditions during in vitro perfusion of 30 human term placentas and related to birth weight (range 2640-4640g), birth weight centile (8th-99th), ponderal index (2.43-3.69), placental weight (418-1030g) and placental:fetal weight (0.14-0.31). There was no statistically significant change in the rate of nutrient transfer per placenta or per kg fetal weight, with birth weight, birth weight centile, ponderal index, placental weight and placental:fetal weight. There was a weak but significant relationship (P=0.020, r(2)=9 per cent) between the ratio of glucose to fatty acid transport and birth weight centile, largely due to the high ratio found in the lowest birth weight quartile where the babies are thinnest. This study provides no evidence that placental nutrient transport capacity limits fetal growth across a wide range of birth weights in normal pregnancies. It is proposed that the fetus itself may regulate placental nutrient transport in vivo via the fetal cardiac output and the rate of fetal nutrient utilization.     

Cesarean section intraoperative blood loss and mode of placental separation.

OBJECTIVE: To investigate whether manual removal of the placenta is associated with significant blood loss compared with spontaneous separation of the placenta during cesarean delivery. DESIGN: A randomized prospective study of 400 women with normal pregnancies undergoing cesarean delivery at King Abdulaziz University Hospital, Jeddah, Saudi Arabia. Patients were randomly assigned to the study group, (manual placental removal, n=200) or the control group (spontaneous placental separation, n=200). Operative blood loss was assessed by the volumetric and gravimetric methods. Hemoglobin levels were evaluated the third postoperative day and patient's postoperative complications were recorded. RESULTS: The mean+/-S.D. amount of blood loss associated with manual and spontaneous removal of the placenta was 713+/-240 and 669+/-253 ml, respectively. This difference was statistically significant (P=0.04). There was a postoperative decrease in hemoglobin levels in both groups. Preoperative hemoglobin levels were 11.6+/-3 g/dl in the study group and 11.2+/-1.1 g/dl in the control group, and the difference was statistically significant (P=0.006). The postoperative hemoglobin levels at day 3 were 9.0+/-1.2 g/dl in the study group and 9.9+/-1.2 g/dl in the control group (P=0.003), also a statistically significant difference. The incidence of endometritis, wound infection, and need for blood transfusion was similar in the two groups. CONCLUSION: Manual delivery of the placenta was significantly associated with greater operative blood loss and greater decrease in postoperative hemoglobin levels, but with shorter operative time compared with spontaneous placental separation. No difference in postoperative complications was noted between the groups.     

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.     

双胎妊娠孕期不同阶段体质量增长速度与母婴结局的关系

目的:分析双胎妊娠孕期不同阶段体质量增长情况与母婴结局的关系。方法:对2013年1月至2015年10月在上海交通大学医学院附属国际和平妇幼保健院住院分娩的472例双胎妊娠产妇的临床资料进行回顾性分析,比较不同孕前BMI孕妇孕期体质量增长情况,在校正年龄和孕前BMI后,使用二元Logistic回归分析孕期不同阶段体质量增长速度与孕期并发症、早产、胎膜早破和新生儿出生体质量的关系。结果:(1)孕早中期平均体质量增长速度0.41±0.15 kg/w,孕晚期平均体质量增长速度0.64±0.30 kg/w,整个孕期平均体质量增长速度0.49±0.15 kg/w。(2)孕晚期和整个孕期体质量增长过快是妊娠期高血压疾病和发生早产的高危因素(P0.05),孕早中期、孕晚期及整个孕期体质量增长过快是发生胎膜早破的高危因素(P0.05),孕早中期及整个孕期的体质量增长过慢是新生儿低出生体质量的高危因素(P0.05)。(3)在校正年龄、孕前BMI、孕周等因素后,孕期体质量每增加1 kg,双胎出生体质量之和增加25.21 g(P0.001);孕早中期每增加1 kg,双胎出生体质量之和增加30.89 g(P0.001);孕晚期每增加1 kg,双胎出生体质量之和增加21.46 g(P=0.001)。结论:双胎妊娠孕期体质量增长与母婴不良结局密切相关,妊娠不同阶段的体质量增长速度对母婴结局有一定的预测价值,应进一步探讨适合中国人群的双胎妊娠孕期体质量增长适宜范围。