PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “gestation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2006

Three weekly courses of betamethasone administered to pregnant baboons at 0.6, 0.65, and 0.7 of gestation alter fetal and maternal lymphocyte populations at 0.95 of gestation.

The hypothalamic-pituitary-adrenal (HPA) axis plays a major role in the communication between the immune and neuroendocrine systems. Glucocorticoids are potent immunomodulatory hormones. In the present study, we evaluated the effect of three weekly courses of betamethasone, administered to pregnant baboons at 0.6, 0.65, and 0.7 of gestation, on maternal hematological parameters during treatment, maternal and fetal hematological parameters and lymphocyte populations at 0.95 of gestation, and fetal lymphoid organs and placental structure. Each weekly betamethasone course resulted in decreased granulocytes and increased lymphocytes and monocytes in maternal circulation (by percentage, p < 0.05). The percentage and absolute number of CD8+ T-cells in the maternal circulation were lower and CD4+ T-cells higher (p < 0.05) in treated pregnant animals at 0.95 gestation. The percentage of proliferating CD3- CD8+ cells was lower in blood obtained from the fetal heart of betamethasone-treated animals. In the betamethasone group, the number of CD8+ T-cells and NK cells were elevated and the number of T and CD4+ T-cells were reduced in fetal heart blood compared with the umbilical vein blood. The number of placental macrophages (CD68+ cells) per visual field in betamethasone-treated and control animals were not different. Taken together, our data show that betamethasone treatment of pregnant females with no indication of preterm labor affects some components of the fetal and maternal immune system, altering the maternal CD4+/CD8+ ratio and absolute number of fetal NK cell and maternal CD8+ T-cell.

Animals↗
PubMed1997

New birth weight nomograms for twin gestation on the basis of accurate gestational age.

OBJECTIVE: Our purpose was to establish new nomograms for the birth weight of twins on the basis of accurate methods to validate gestational age. STUDY DESIGN: The medical records of 1632 consecutive twin gestations delivered between 1984 and 1996 were reviewed. Only pregnancies induced by ovulation induction techniques or that were measured ultrasonographically for crown-rump length during the first trimester were included. Excluded were those whose fetuses (one or both) were stillborn, or if the mother smoked, had a significant chronic illness, or was prescribed any regular medications. The study comprised 520 twin pregnancies at 28 to 41 gestational weeks at delivery. RESULTS: The median and 10th and 90th percentile birth weight curves were calculated for the studied twins and plotted against previously reported singleton nomograms. Fetuses of twin pregnancies were found to be growth restricted in comparison with previously reported singletons throughout the third trimester. This trend became more evident after the thirty-fourth to thirty-sixth weeks. CONCLUSIONS: We recommend these novel birth weight nomograms for clinical use in the management of twin pregnancies.

Birth Weight↗
PubMed1988

Lean body mass in small for gestational age and appropriate for gestational age infants.

Dual photon absorptiometry using 153Gd in a whole-body scanner was used to measure lean body mass (LBM) in 51 newborn infants. LBM% decreased exponentially with increasing gestational age in both small for gestational age (SGA) and appropriate for gestational age (AGA) infants. In preterm SGA and AGA infants LBM was 104% and 103%, respectively, indicating that no fat was detectable. In term SGA infants LBM was 98%, which corresponded to 48 gm fat on average, and in term AGA infants LBM was 87%, which corresponded to 452 gm fat on average. The LBM%, ponderal index, and skinfold thickness were significantly different between AGA and SGA infants. Infants with clinical signs of intrauterine wastage had significantly higher LBM% than did infants without signs of weight loss. Our results on LBM% by dual photon absorptiometry agree with earlier dissection data; the clinically applicable methods of (1) height combined with weight (i.e., ponderal index), (2) skinfold thickness, and (3) scoring by clinical observations are useful for the estimation of lack of fat as an indicator of intrauterine growth retardation.

Adipose Tissue↗
PubMed2001

Undernutrition during the first half of gestation increases the predominance of fetal tissue in late-gestation ovine placentomes.

OBJECTIVE: To investigate, in sheep, the effects of maternal undernutrition during the first half of pregnancy on placental growth and development and fetal growth. STUDY DESIGN: Six ewes (R) were subjected to a 15% reduction in nutrient intake for the first 70 days of gestation and thereafter received the recommended daily intake. Another group of six ewes (C) received the recommended daily intake throughout pregnancy. At 130 days gestation the ewes were killed and morphological and morphometrical measurements were carried out on the placenta and fetus. RESULTS: Undernutrition resulted in a significant alteration in placental morphology, which was seen as increased growth of the fetal side of the placenta in R animals. However, fetal size in late gestation was not affected by the undernutrition, suggesting that placental adaptation was successful in maintaining fetal growth. CONCLUSION: Placental adaptations, including changes in gross morphology, may preserve fetal growth if maternal undernutrition is not severe. The mechanisms remain to be elucidated.

Animals↗
PubMed2002

Impact of preeclampsia and gestational hypertension on birth weight by gestational age.

The predominant etiologic theory of preeclampsia is that reduced uteroplacental perfusion is the unique pathogenic process in the development of preeclampsia. Decreased uteroplacental blood flow would result in lower birth weights. To date, no study has assessed the effect of preeclampsia on birth weight by gestational age. Thus, the authors conducted a retrospective cohort study based on 97,270 pregnancies that resulted in delivery between 1991 and 1996 at 35 hospitals in northern and central Alberta, Canada. Differences in mean birth weight between women with preeclampsia and normotensive women ranged from -547.5 g to 239.5 g for gestational age categories ranging from < or = 32 weeks to > or = 2 weeks. The birth weights were statistically significantly lower among mothers with preeclampsia who delivered at < or = 37 weeks, with an average difference of -352.5 g. However, the birth weights were not lower among preeclamptic mothers who delivered after 37 weeks (average difference of 49.0 g). In Alberta, 61.2% of preeclamptic patients gave birth after 37 weeks of gestation. The authors conclude that babies born to mothers with preeclampsia at term have fetal growth similar to that of babies born to normotensive mothers. This finding does not endorse the currently held theory that reduced uteroplacental perfusion is the unique pathophysiologic process in preeclampsia.

Adolescent↗
PubMed1999

Interleukin-8 release from human gestational tissue explants: effects of gestation, labor, and chorioamnionitis.

Interleukin-8 (IL-8) is a chemotactic cytokine that has been implicated in the process of human parturition, including the processes of cervical ripening and rupture of fetal membranes. In this study, the in vitro release of IL-8 from human amnion, choriodecidua, and placenta tissues obtained before and after spontaneous labor onset both at term and preterm, was assessed. The effect of chorioamnionitis on IL-8 release was also established. All tissue explants examined released IL-8; however, IL-8 release from choriodecidual explants was significantly (p < 0.02) greater than that observed from amnion and placenta. Furthermore, choriodecidual IL-8 release was significantly (p < 0.001) greater from term tissues (850 +/- 134.4 ng/mg DNA, n = 18) than from preterm tissues (458 +/- 68.8 ng/mg DNA, n = 17). Spontaneous onset of labor, irrespective of the eventual mode of delivery, was not associated with any significant changes in IL-8 release from human gestational tissues compared to not-in-labor tissues, both at term and preterm. IL-8 release from gestational tissues was not significantly different in the absence or presence of chorioamnionitis. These data are in contrast to the previously reported stimulatory effects of bacterial endotoxin on IL-8 release from human gestational tissues. The data are consistent, however, with the suggestion that IL-8 release is an early event in chorioamnionitis that precedes the appearance of clinically overt symptoms.

Amnion↗
PubMed1990

The transverse cerebellar diameter cannot be used to assess gestational age in the small for gestational age fetus.

The transverse cerebellar diameter was obtained in 44 small for gestational age (SGA) fetuses between 27-42.8 weeks. Twenty-nine of 44 fetuses had antepartum and/or neonatal complications consistent with intrauterine growth retardation. The cerebellar diameter was normal in 12 (27.3%), between 1-2 SDs below the mean for gestational age in six (13.6%), and greater than 2 SDs below the mean in 26 (59.1%). Hence, the transverse cerebellar diameter cannot be used to assess gestational age in those fetuses suspected of being SGA.

Cerebellum↗
PubMed1983

Decreased bone mineral content in small-for-gestational-age infants compared with appropriate-for-gestational-age infants: normal serum 25-hydroxyvitamin D and decreasing parathyroid hormone.

Bone mineral content was determined by photon absorptiometry, adapted for use in neonates, in 23 small-for-gestational-age (SGA) infants of 31 to 42 weeks of gestational age, for 12 weeks. At birth, term SGA infants had lower bone mineral content than term appropriate-for-gestational-age (AGA) infants; postnatal increase in bone mineral content was slow and lagged significantly behind that of term AGA infants. Preterm SGA infants had bone mineral content that was similar to that of preterm AGA infants at birth; postnatal bone mineral content was similar to that of preterm AGA infants, but was decreased compared with the expected intrauterine bone mineral content. Serum 25-hydroxyvitamin D concentrations and parathyroid hormone levels were the same for SGA and AGA infants. Serum 25-hydroxyvitamin D concentrations decreased slightly with postnatal age and remained within normal limits. Serum parathyroid hormone concentrations decreased in both SGA and AGA infants and reached undetectable levels at 10 to 12 weeks of age.

25-Hydroxyvitamin D 2↗
PubMed2003

Cervical length at 11-14 weeks' and 22-24 weeks' gestation evaluated by transvaginal sonography, and gestational age at delivery.

OBJECTIVE: To compare cervical length measurements obtained at 11 to 14 weeks and 22 to 24 weeks of gestation in an unselected group of pregnant women and to correlate the measurements with time of delivery. METHODS: This was a prospective study involving 529 pregnant women attending for routine antenatal care who underwent transvaginal scans at 11-14 weeks and 22-24 weeks for evaluation of cervical length. The mean cervical length was calculated at both stages of gestation and lengths were compared between groups which delivered at term or prematurely, this being defined as delivery before 37 completed weeks of gestation. RESULTS: The mean cervical lengths at 11-14 and 22-24 weeks were, respectively, 42.4 mm and 38.6 mm. Cervical length at 11-14 weeks was not significantly different between the groups which delivered at term (42.7 mm) and preterm (40.6 mm). However, at the 22-24-week evaluation, cervical length was significantly shorter in the group which had a preterm delivery than in that which had a term delivery (26.7 mm and 39.3 mm, respectively; P = 0.0001). In the group of women with a previous history of one or more preterm deliveries, there was a greater shortening in cervical length from the first to the second evaluation than there was in the group of women with no previous history of preterm delivery. This shortening was also more pronounced in the group which delivered prematurely (from 40.6 mm to 26.7 mm) than in that which delivered at term (from 42.7 mm to 39.3 mm). CONCLUSION: There is a spontaneous shortening in the pregnant cervix from the first to the second trimester of pregnancy. The shortening is more rapid in pregnant women who deliver prematurely and who have a history of previous preterm delivery.

Adolescent↗
PubMed1985

Frequency of diabetes mellitus in mothers of probands with gestational diabetes: possible maternal influence on the predisposition to gestational diabetes.

Interviews for genetic histories were conducted prior to delivery in 166 pregnant diabetic probands and 83 control gravidas with normal carbohydrate metabolism throughout gestation. A significant association was observed between parental diabetic phenotypes and type of diabetes in the probands (chi 2(12)) = 32.413; p less than 0.001). In particular a higher than expected number of mothers with diabetes was encountered in 91 probands with gestational diabetes mellitus. The findings are examined in relationship to the hypothesis that vulnerability to gestational diabetes may be increased by exposure to an abnormal environment during intrauterine development.

Adult↗
PubMed1996

Peripheral cortisol levels throughout gestation in the cow: effect of stage of gestation and foetal number.

This study characterized the peripheral plasma cortisol profile throughout gestation and examined the effect of stage of gestation and foetal number in Holstein cows after non-surgical embryo transfer. Cows (n = 10) were divided into two groups: Group 1 = single embryo recipient cows (n = 5); and group 2 = twin-embryo recipient cows (n = 5). Mean plasma cortisol concentrations remained basal (2-4 ng ml-1) in both groups up to 2 days prepartum increased significantly (P < 0.05) to peak at parturition day, and then declined rapidly 1 day post-partum. Twin-bearing cows had significantly (P < 0.01) higher mean plasma cortisol concentration on the day of parturition than in the singleton cows. There was no effect of the stage of gestation on cortisol levels in either group (P > 0.1), except in the last 48 h prior to parturition. A single cow giving birth prematurely had 100% higher plasma cortisol levels on the day of parturition and 1 day post-partum than cows giving birth at term.

Animals↗
PubMedDate not supplied

[Anencephaly at 20 weeks gestation. What is the optimal gestational age for early diagnosis?].

Anencephaly is a lethal defect resulting from a disturbed closure of the neural tube. Prenatal diagnosis during first-trimester-scan is essential but implies pitfalls. Three findings of anencephaly at 20 weeks gestation are reported. Fetuses with anencephaly are correctly identified at 12 to 13 weeks gestation. Anencephaly occurs in absence of the cranial vault. Ultrasound findings can be normal until onset of ossification has definitely failed. A first trimester scan at 12 to 13 weeks allows reliable diagnosis and active management of anencephaly. At this gestational age fetal anatomy can be screened in detail by transvaginal ultrasound and nuchal translucency can be measured.

Abnormalities, Multiple↗
PubMed1991

Lack of effect of melatonin on myometrial electromyographic activity in the pregnant sheep at 138-142 days gestation (term = 147 days gestation).

A 24-h rhythm has been demonstrated in fetal and maternal melatonin plasma concentrations in pregnant sheep in the last third of gestation. Melatonin in the maternal circulation can cross the placenta and is the major source of melatonin in the fetal circulation. Melatonin has been postulated to act as a prostaglandin (PG) synthetase inhibitor in the uterus. PG synthetase inhibitors decrease myometrial contractility. To assess transplacental passage of melatonin and potential influences of melatonin on uterine contractility, we infused melatonin continuously into the maternal jugular vein in seven pregnant sheep at 138-142 days gestation (term in our instrumented animals is 147 days gestation) at three infusion rates for successive 1-h periods during the late morning to late afternoon. There was no change in the total time during which the myometrium was active, as indicated by myometrial electromyographic activity or the myometrial contracture frequency during the 3 h before and after melatonin infusions and for each hour of the infusions. The MCR for melatonin in the ewe was 4128 +/- 410 ml/min (mean +/- SE; n = 7; weight, 50-70 kg). The resting maternal to fetal melatonin concentration ratio was 0.8; this ratio was maintained at 2.28 during melatonin infusion to the ewe at a wide range of maternal melatonin concentrations. Melatonin concentrations in the range of 3-200 times normal had no effect on the maternal plasma PGF2 alpha metabolite concentration, but caused a 40.4% fall in fetal plasma PGE2 (P less than 0.05). We conclude that changes in maternal and fetal plasma melatonin concentrations within the physiological range observed throughout the day do not alter myometrial contractility, but do alter fetal PGs.

Animals↗
PubMed2001

Human chorionic gonadotropin (hCG) beta-core fragment is produced by degradation of hCG or free hCG beta in gestational trophoblastic tumors: a possible marker for early detection of persistent postmolar gestational trophoblastic disease.

The present study was undertaken to investigate whether human chorionic gonadotropin (hCG) beta-core fragment (hCG beta cf) was directly produced by gestational trophoblastic tumors. Immunoreactivity of hCG beta cf was demonstrated in the extracts as well as in the culture media of hydatidiform mole tissues. It was also present in the extracts of choriocarcinoma tissues, and its molar concentration exceeded that of intact hCG. The presence of hCG beta cf was then confirmed by gel chromatography and Western blot analysis. Immunohistochemistry showed localization of hCG beta cf immunoreactivity to the syncytiotrophoblasts and scattered cells in the stroma of mole tissue, and to syncytiotrophoblastic cells in choriocarcinoma. Immunoreactivity of hCG beta cf was also detected in the sera of the patients with gestational trophoblastic disease, although the hCG beta cf/hCG ratio was less than one hundredth of that in the tissue extracts. Serial measurement of serum hCG beta cf levels after mole evacuation showed that they declined much more rapidly than those of hCG and became undetectable in the patients with subsequent spontaneous resolution, while hCG beta cf remained or became detectable before the rise of hCG was observed in the patients with subsequent persistent trophoblastic disease. Taken together, these results suggest that hCG beta cf is directly produced by gestational trophoblastic tumors, and monitoring of hCG beta cf in the serum after mole evacuation may be useful for early prediction of subsequent development of postmolar persistent trophoblastic disease.

Animals↗
PubMedDate not supplied

Gestational hyperlipidemic pancreatitis without non-gestational hyperlipidemia.

A 27 year-old pregnant woman was referred to our department with nausea, abdominal pain, and hypertriglyceridemia (5500 mg/dl). A diagnosis of acute gestational hyperlipidemic pancreatitis was made. She had no history of nongestational hyperlipidemia. Subsequently, she underwent pancreatic drainage and Caesarean section. Our experience suggests that gestational hyperlipidemic pancreatitis may occur in pregnant women without nongestational hyperlipidemia. Intensive monitoring of serum lipid levels is mandatory when managing pregnant women who develop or show gestational worsening of hypertriglyceridemia.

Acute Disease↗
PubMed1999

Bivariate logistic regression: modelling the association of small for gestational age births in twin gestations.

Clustered binary responses, such as disease status in twins, frequently arise in perinatal health and other epidemiologic applications. The scientific objective involves modelling both the marginal mean responses, such as the probability of disease, and the within-cluster association of the multivariate responses. In this regard, bivariate logistic regression is a useful procedure with advantages that include (i) a single maximization of the joint probability distribution of the bivariate binary responses, and (ii) modelling the odds ratio describing the pairwise association between the two binary responses in relation to several covariates. In addition, since the form of the joint distribution of the bivariate binary responses is assumed known, parameters for the regression model can be estimated by the method of maximum likelihood. Hence, statistical inferences may be based on likelihood ratio tests and profile likelihood confidence intervals. We apply bivariate logistic regression to a perinatal database comprising 924 twin foetuses resulting from 462 pregnancies to model obstetric and clinical risk factors for the association of small for gestational age births in twin gestations.

Adolescent↗
PubMed1998

Phosphoisoforms of insulin-like growth factor binding protein-1 in appropriate-for-gestational-age and small-for-gestational-age fetuses.

We analysed phosphoisoforms of insulin-like growth factor binding protein-1 (IGFBP-1) in maternal and cord sera from preterm and term fetus with different growth status. Phosphoisoforms were separated by non-SDS-polyacrylamide gel electrophoresis and detected by immunoblot. Phosphoisoforms were also analysed by anion exchange chromatography on HPLC. The proportion of non-phosphorylated IGFBP-1 to total IGFBP-1 was significantly higher in preterm fetus than in their mothers, however, the relative amounts of each IGFBP-1 isoforms were similar between preterm and term fetus. The levels of non-phosphorylated IGFBP-1 were similar between appropriate for gestational age (AGA) and small for gestational age (SGA) fetus at term, however, phosphorylated isoforms of IGFBP-1 were increased in SGA fetus compared to those of AGA fetus and the proportion of non-phosphorylated IGFBP-1 to total IGFBP-1 was lower in SGA fetus than those in AGA fetus. Thus, the profiles of non-phosphorylated and phosphorylated IGFBP-1 in the fetus varies corresponding to fetal growth suggesting that not only total amounts of IGFBP-1 but also the proportion of phosphoisoforms of IGFBP-1 is important for fetal growth.

Biomarkers↗