Factors Affecting Fetal Growth And Development Pdf
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The maternal intrauterine environment as a generator of children at risk of metabolic syndrome: a review. Universidade Federal de Pernambuco. Moraes Rego, Recife, PE, Brasil. CEP:
Maternal nutritional and metabolic factors influence the developmental environment of the fetus. Virtually any nutritional factor in the maternal blood has to pass the placental membranes to reach the fetal blood. Placental weight is a commonly used measure to summarize placental growth and function.
Placental weight is an independent determinant of fetal growth and birthweight and modifies the associations between maternal metabolic factors and fetal growth.
We hypothesized that maternal factors known to be related to fetal growth, newborn size and body composition are determinants of placental weight and that effects of maternal metabolic factors on placental weight differ between the genders. The STORK study is a prospective longitudinal study including healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants parity, body mass index, gestational weight gain and fasting plasma glucose of placental weight were explored by linear regression models, stratified by fetal sex.
Parity, maternal BMI, gestational weight gain and fasting glucose had positive effects on placental weight. There was a sex specific effect in these associations. Fasting glucose was significantly associated with placental weight in females but not in males. Maternal factors known to influence fetal growth, birthweight and neonatal body composition are determinants of placental weight.
The effect of maternal factors on placental weight is influenced by sex as illustrated in the relation between maternal glucose and placental weight. This is an open-access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Maternal nutritional and metabolic conditions determine the environment in which the fetus develops . We have reported similar findings in our previous work  — . In contrast to the HAPO study we have considered placental weight as a determinant of fetal growth in addition to the maternal factors.
The placenta plays a major role in fetal nutrition and fetal growth as nutrients from the maternal circulation need to be transported across the placenta to reach the fetal circulation .
Furthermore, the placenta itself metabolizes some of the nutrients taken up by the placenta, thereby making the placenta more than a passive conduit of nutrient transport .
We have previously illustrated the mediating effect of placental weight in the associations between maternal factors and three different measures of fetal growth; birthweight, intrauterine fetal growth and neonatal fat percentage  , .
Placenta is an organ weighing 0. The main constituent of the placenta is the villous tissue. In late pregnancy it makes up a 12—14 m 2 physical interphase separating maternal and fetal blood  ,  and consists mainly of two cell layers, the syncytiotrophoblast on the maternal side and capillary endothelial cells on the fetal side . Virtually any nutritional or other factor on the maternal side has to pass through the syncytio-endothelial membrane to reach the fetal blood.
In addition to mediate transport of nutritional and metabolic compounds the syncytiotrophoblast works as an endocrine organ that releases a number of hormones and growth factors to the maternal circulation. These factors effectuate profound metabolic and vascular alterations in the maternal body securing adequate conditions for fetal development .
Placental weight is a measure commonly used to summarize placental growth and aspects of placental function. In normal pregnancy it is reasonable to assume that placental weight is related to aspects of functional capacity of the placenta . The surface area of the villous tissue, a main determinant of the capacity to transport nutrients, is linearly related to placental weight  , as is maternal plasma levels of placental hormones .
Accordingly, factors that determine placental weight may also be important determinants of functional capacities of placenta and fetal nutritional conditions. Placental size can be affected by changes in maternal nutrition.
Data from pregnancies during the Dutch famine showed that placental area was reduced . In the second and third trimester of pregnancy the changes in maternal diet in the month of Ramadan were associated with reduced placental weight .
There are sex differences in weight and body composition at birth  , differences that may have impact on the future health of the newborn. Sex differences have also been reported in placental size.
In the Dutch famine placental area among boys were reduced, but less so in girls . A similar trend was observed in the Ramadan study . In the present study, we hypothesized that maternal factors known to be related to fetal growth, newborn size and body composition are determinants of placental weight.
Based on previous observations of ours, we also hypothesized that the effects of maternal metabolic factors on placental weight differ between the genders. To study the effects of maternal factors parity, BMI, gestational weight gain and fasting glucose on placental weight, stratified by fetal sex.
All participants signed a written informed consent. The STORK study is a prospective cohort study with a longitudinal design including healthy women of Scandinavian heritage with singleton pregnancies who gave birth at Oslo University Hospital, Rikshospitalet between and Exclusion criteria were multiple pregnancies, known pre-gestational diabetes and severe chronic diseases lung, cardiac, gastrointestinal or renal , and pregnancies with fetal malformations discovered at the routine scan in week 18 of pregnancy.
Only 37 were lost to follow up, mostly because some participants moved to a different area during pregnancy and some accidentally delivered at a different hospital. Details about the inclusion of patients have been published . Each pregnant woman had four antenatal visits, scheduled at weeks 14—16 visit 1 , weeks 22—24 visit 2 , weeks 30—32 visit 3 and weeks 36—38 visit 4.
Clinical data and blood samples were collected at each visit. Parity was coded as P0 for nulliparous women and P1 for those with one or more previous births. Weight was measured by a calibrated scale at each visit.
Gestational weight gain GWG was calculated as both the total GWG difference between weights measured at visit 4 and visit 1 and weight gain between each visit. Measured weight at the first visit was used instead of pre pregnancy weight to avoid recall bias.
Blood samples were drawn in the morning after an overnight fast. Due to an unexpected increasing trend in fasting plasma glucose over time, the glucose values were statistically adjusted . Placental weight including cord and membranes was measured by the midwife within one hour after the delivery. Descriptive data are reported as mean and standard deviations or numbers and percentage as appropriate and are shown in Table 1 and 2.
The outcome variable was placental weight g. The maternal characteristics chosen as independent variables were parity, BMI measured at visit 1 weeks 14—16 , total GWG between visit 1 and visit 4 , GWG between each visit and fasting plasma glucose at visit 1 and 3.
There was no multicollinearity between the variables. All analyses were adjusted for gestational age since placental weight depends on gestational age. The associations between maternal characteristics and placental weight were analyzed by univariate and multiple linear regression models.
This analysis was then repeated, stratified by fetal sex Table 4 and 5. We included only one measurement of fasting glucose in the multiple model at the time.
Only fasting glucose at visit 3 remained statistically significant and was included in the final model. The mean birthweight was g SD and mean gestational age at birth was Mean placental weight was g SD Only 2. Boys were heavier g vs. Boys also had a higher fetal: placental ratio than girls 5. These differences remained statistically different when corrected for gestational age.
There were no statistically significant differences between mothers of boys and mothers of girls in parity, maternal BMI, GWG or fasting glucose 0. Several maternal characteristics had a positive effect on placental weight, including parity, maternal BMI, GWG and fasting glucose Table 3. Adjusted estimates showed that multipara had nearly 30 g heavier placentas than primipara, one unit higher BMI gave 6.
GWG had an independent positive effect on placental weight. In the multiple models fasting glucose at visit 3 was significantly associated with placental weight in females but not in males. Fasting glucose at visit 1 was significant in univariate analyses, but was non-significant in the multiple models for the total cohort as well as for girls and boys separately.
In the final models, we therefore included fasting glucose measured at visit 3. In the present study, we found that parity, BMI, GWG, fasting glucose at visit 3 and gestational age had positive, independent effects on placental weight. Our study showed that an increase of one unit of BMI increased placental weight by 7. The linear association between increasing BMI in categories and placental weight was convincingly illustrated by Wallace et al.
Our effect estimates were based on BMI as a continuous variable. By categorizing our data, we found a similar linear association data not shown. A Dutch study on determinants of placental weight reported an effect of pre-pregnancy BMI of 5. Given the current finding that BMI influences placental weight, our results are compatible with the concept that some of the effect of BMI on birthweight is mediated through a promotion of placental growth.
Apart from glucose, there are possibly other biological factors related to BMI that exert an effect on placental growth. Which factors are still to be elucidated.
However, we recently reported that maternal plasma total cholesterol was positively associated with placental weight, whereas HDL cholesterol had a negative effect . Multipara in our study had Data from the Aberdeen study referred to above was used to create placental weight charts specific for gestational age, gender and parity. This study showed that the difference between boys and girls in placental weight was approximately 15 g regardless of parity, whereas the effect of parity was larger, approximately 27 g for both girls and boys .
Total GWG was restricted to the difference between weight measured at visit 4 and weight measured at visit 1. Pre-pregnancy weight could have introduced a recall bias that generally is difficult to estimate and we did not have complete data on weight measured at delivery.
Our results showed that it was GWG between visit 1 and visit 2 that was significantly associated with placental weight, whereas GWG after visit 2 did not show a significant association. Hence, GWG in early pregnancy had a positive effect on placental weight.
This finding is in accordance with a study by Diouf and coworkers who found that weight gain in the first trimester was positively associated with birthweight. Path analysis indicated that this was not a direct effect of weight gain on birthweight, but rather an effect mediated by placental weight . Maternal weight gain in early pregnancy is a placental hormone driven increase in plasma volume and fat stores making the association between early GWG and placental mass biologically plausible.
Fasting glucose at visit 3 was positively associated with placental weight in the total cohort, but when stratified by fetal sex the effect was only significant for the females. Previous results from our group showed that fasting glucose was associated with birthweight in girls, not in boys .
Factors Influencing Fetal Growth
Maternal nutritional and metabolic factors influence the developmental environment of the fetus. Virtually any nutritional factor in the maternal blood has to pass the placental membranes to reach the fetal blood. Placental weight is a commonly used measure to summarize placental growth and function. Placental weight is an independent determinant of fetal growth and birthweight and modifies the associations between maternal metabolic factors and fetal growth. We hypothesized that maternal factors known to be related to fetal growth, newborn size and body composition are determinants of placental weight and that effects of maternal metabolic factors on placental weight differ between the genders.
Prenatal development is highly influenced by the inheritance, expression, and regulation of genes. Developmental psychologists consider the process of human development as it relates to physical, cognitive, and psychosocial development. Prenatal development is the process that occurs during the 40 weeks prior to the birth of a child, and is heavily influenced by genetics. There are three stages of prenatal development— germinal, embryonic, and fetal. Prenatal development is also organized into trimesters: the first trimester ends with the end of the embryonic stage, the second trimester ends at week 20, and the third trimester ends at birth. Every person is made up of cells, each of which contains chromosomes.
Genetic, nutritional, environmental, uteroplacental, and fetal factors have been suggested to influence fetal growth. Uteroplacental and umbilical blood flow and transplacental glucose and fetal insulin are major determinants of fetal growth.
Factors influencing fetal growth
Selective transcriptions are coupled with proteosynthesis, nonselective with cell division. Growth means increase in size due to an increase of existing structural and functional units. Differentiation is a process whereby a relatively simple system is changed into a more complicated one.
A fetus also foetus is a developing mammal after the embryonic stage and before birth. In humans, a fetus develops from the end of the 8th week of pregnancy when the major structures have formed , until birth. Maternal factors include maternal size, weight, weight for height, nutritional state, anemia, high environmental noise exposure, cigarette smoking, substance abuse, or uterine blood flow.
Чтобы предотвратить дальнейшее проникновение в государственные секреты, вся наиболее важная информация была сосредоточена в одном в высшей степени безопасном месте - новой базе данных АНБ, своего рода форте Нокс разведывательной информации страны. Без преувеличения многие миллионы наиболее секретных фотографий, магнитофонных записей, документов и видеофильмов были записаны на электронные носители и отправлены в колоссальное по размерам хранилище, а твердые копии этих материалов были уничтожены. Базу данных защищали трехуровневое реле мощности и многослойная система цифровой поддержки. Она была спрятана под землей на глубине 214 футов для защиты от взрывов и воздействия магнитных полей. Вся деятельность в комнате управления относилась к категории Совершенно секретно. УМБРА, что было высшим уровнем секретности в стране. Никогда еще государственные секреты США не были так хорошо защищены.
- спросил немец с расширившимися от страха глазами. - Или мы придем к соглашению.
После минутного упорства ему придется уступить. Но если я вызову агентов безопасности, весь мой план рухнет, - подумал. Хейл сдавил горло Сьюзан немного сильнее, и она вскрикнула от боли. - Ну что, вы решили.
Нужно быстро пройти в кабинет Стратмора, но, конечно, не чересчур быстро: Хейл не должен ничего заподозрить. Она уже была готова распахнуть дверь, как вдруг до нее донеслись какие-то звуки. Это были голоса. Мужские голоса. Они долетали до нее из вентиляционного люка, расположенного внизу, почти у пола.
Сьюзан это не удивило.
Тот поднес его к глазам и рассмотрел, затем надел его на палец, достал из кармана пачку купюр и передал девушке. Они поговорили еще несколько минут, после чего девушка обняла его, выпрямилась и, повесив сумку на плечо, ушла. Наконец-то, подумал пассажир такси.