Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Parturition”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 487 records · Page 27Linked to original sources
PubMed2006

Immune response and serum immunoglobulin G concentrations in beef calves suckling cows of differing body condition score at parturition and supplemented with high-linoleate or high-oleate safflower seeds.

Two experiments were conducted to determine the effect of maternal lipid supplementation on the immune response to antigenic challenge in suckling calves. In Exp. 1, beginning 1 d postpartum, 18 primiparous crossbred beef cows were fed Foxtail millet hay and a low-fat (control) supplement or a supplement containing cracked, high-linoleate safflower seed in individual feeding stanchions until d 40 of lactation. The diets were formulated to provide similar quantities of N and TDN, and the linoleate diet was formulated to contain 5% of DMI as fat. Calves were injected s.c. with 15 mg of antigen (ovalbumin) at d 21 and again at d 35 of age. To measure the total serum antibody production in response to the antigen, blood samples were collected from the calves every 7 d via jugular venipuncture from d 14 to 42. Calves from linoleate-supplemented cows had a decrease (P = 0.04) in total antibody production in response to ovalbumin and appeared to have a delayed response to antigen challenge. Total antibody production increased (P < 0.001) after secondary exposure to ovalbumin. In Exp. 2, 36 Angus x Gelbvieh beef cows that were nutritionally managed to achieve a BCS of 4 or 6 at parturition were used to determine the effects of prepartum energy balance and postpartum lipid supplementation on the passive transfer of immunoglobulins and the immune response to antigenic challenge in their calves. Beginning at 3 d postpartum and continuing until d 60 of lactation, cows were fed hay and a low-fat control supplement or supplements consisting of either cracked, high-linoleate or high-oleate safflower seeds. Safflower seed supplements were formulated to provide 5% of DMI as fat. Calves were injected s.c. with 15 mg of ovalbumin at 21 d of age and again at 48 d of age. The antibody responses were determined in serum; cell-mediated immunity was assessed by intradermal antigen injection at 60 d of age. A trend was noted (P = 0.10) for calves suckling control-supplemented cows to have a greater response to antigen compared with calves from linoleate- and oleate-supplemented cows; however, no difference was observed among treatments (P = 0.86) in cell-mediated immune response. Postpartum oilseed supplementation in beef cows appears to decrease antibody production in response to antigenic challenge in suckling calves. However, BCS at parturition did not influence passive transfer of immunoglobulins in neonatal calves.

Animal Feed↗
PubMed2006

Effects of postpartum dietary fat and body condition score at parturition on plasma, adipose tissue, and milk fatty acid composition of lactating beef cows.

Two experiments were conducted with lactating Angus x Gelbvieh beef cows to determine the effects of postpartum lipid supplementation, BCS at parturition, and day of lactation on fatty acid profiles in plasma, adipose tissue, and milk. In Exp. 1, 36 pri-miparous cows (488 +/- 10 kg of initial BW; 5.5 +/- 0.02 initial BCS) were given ad libitum access to hay and assigned randomly to a low-fat (control) supplement or supplements with cracked, high-linoleate safflower seeds (linoleate) or cracked, high-oleate safflower seeds (oleate) from d 3 to 90 of lactation. Diets were formulated to be isonitrogenous and isocaloric; safflower seed diets provided 5% of DMI as fat. Plasma and milk samples were collected on d 30, 60, and 90 of lactation. Adipose tissue biopsies were collected near the tail-head region of cows on d 45 and 90 of lactation. In Exp. 2, 3-yr-old cows achieving a BCS of 4 +/- 0.07 (479 +/- 36 kg of BW) or 6 +/- 0.07 (580 +/- 53 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr). Beginning 3 d postpartum through d 61 of lactation, cows were fed diets similar to those of Exp. 1. Adipose tissue and milk samples were collected on d 30 and 60, and plasma was collected on d 31 and 61 of lactation. Responses to postpartum dietary treatment were comparable in both experiments. Cows fed linoleate and oleate had greater (P < 0.001) total fatty acid concentrations in plasma than cows fed control. Except for 15:1, milk fatty acids with <18 carbons were greatest (P < or = 0.01) for cows fed control, whereas milk from cows fed linoleate had the greatest (P < or = 0.02) 18:1trans-11, 18:2n-6, and cis-9, trans-11 CLA. Milk from cows fed oleate had the greatest (P < 0.001) 18:1cis-9. In Exp. 1, total fatty acid concentrations in adipose tissue samples decreased at d 90 compared with d 45 of lactation, but the fatty acid profile of cow adipose tissue was not affected (P = 0.14 to 0.80) by dietary treatment. In Exp. 2, the percentage of cis-9, trans-11 CLA in adipose tissue of cows with a BCS of 6 decreased (P = 0.001) from d 30 to 60 of lactation. Plasma and milk fatty acid composition reflected alterations in postpartum diet. Less medium-chain fatty acids and more 18-carbon fatty acids in milk were indicative of reduced de novo fatty acid synthesis in the mammary gland of beef cows fed lipid supplements; however, the metabolic demands of lactation prevented the deposition of exogenously derived fatty acids in adipose tissue through d 90 of lactation.

Adipose Tissue↗
PubMed2004

Influence of parturition and diets enriched in n-3 or n-6 polyunsaturated fatty acids on immune response of dairy cows during the transition period.

The objectives of this study were to evaluate the functional properties of immunocompetent cells in dairy cows fed diets enriched in n-3 or n-6 polyunsaturated fatty acids during the transition period. Six weeks before calving, 21 primiparous and 27 multiparous pregnant Holstein dairy cows were randomly allotted to 1 of 3 dietary fat treatments: calcium salts of palm oil (Megalac), micronized soybeans, or whole flaxseed, which are, respectively, rich in saturated, n-6, or n-3 fatty acids. On wk 6 and 3 before parturition, cows received a subcutaneous injection of ovalbumin to measure the antibody response in colostrum and serum. Colostrum samples were collected at the first milking after calving, and blood samples were taken 6, 3, and 1 wk before the expected calving date and 1, 3, and 6 wk after calving. Blood mononuclear cells were cultured to evaluate the proliferative response to concanavalin A and the in vitro productions of interferon-gamma, tumor necrosis factor-alpha, nitric oxide, and prostaglandin E2. The serum antibody response to ovalbumin was unaffected by dietary fatty acids, but the response was lower in primiparous cows than in multiparous cows. A significant diet x parity interaction indicated that colostral antibody level against ovalbumin was significantly higher in multiparous cows fed soybeans than in those fed flaxseed or Megalac; there was no difference among treatments for primiparous cows. The lymphocyte response to concanavalin A was lower in cows fed soybeans than in those receiving flaxseed or Megalac when the cells were incubated with autologous serum. The proliferative response of mononuclear cells incubated with autologous serum was suppressed in the 1st wk after calving in both primiparous and multiparous cows, and multiparous cows showed a higher response than primiparous cows throughout the experiment. There was a significant interaction between parity and diet as a result of a greater production of interferon-gamma by mononuclear cells incubated with autologous serum in multiparous cows than in primiparous cows fed flaxseed; there was no difference among cows fed the other diets. Interferon-gamma production was reduced around calving while the inverse was observed for productions of nitric oxide and tumor necrosis factor-alpha. Productions of nitric oxide, prostaglandin E2, and tumor necrosis factor-gamma were greater in primiparous cows than in multiparous cows. In conclusion, functional properties of lymphocytes and monocyte/macrophage lineage of dairy cows during the transition period are modulated by parturition and the composition of polyunsaturated fatty acids in the diet.

Animals↗
PubMed2005

Lymphocyte functions in overconditioned cows around parturition.

The objective of the study was to evaluate the relationships between body condition and lymphocyte functions in periparturient dairy cows. Thirty days before expected calving, 21 Holstein cows were categorized as thin (n = 6), medium (n = 8), or overconditioned (n = 7) based on body condition score (BCS). Blood samples were collected on 21, 14, 7, and 3 d before calving and on d 3, 7, 14, 21, 28, and 35 after parturition. An aliquot of blood was used to determine plasma nonesterified fatty acids (NEFA) and glucose. At 14 and 7 d before, and 14 and 35 d after calving, a second aliquot of blood was used to assess peripheral blood mononuclear cell (PBMC) functions: DNA synthesis, immunoglobulin (Ig) M, and interferon-gamma (IFN-gamma) secretion after mitogen stimulation. During the experiment, all 21 cows showed a decline in BCS. Overconditioned cows lost significantly more BCS than thin cows. After calving, overconditioned cows had higher plasma NEFA compared with thin and medium cows. Conversely, plasma glucose never differed between the 3 categories of cows. Regardless of BCS, DNA synthesis and IgM secretions were significantly lower in PBMC isolated on 7 d before calving compared with those recorded 14 and 35 d after parturition. Conversely, PBMC from the 21 cows did not show any change of IFN-gamma secretion during the experimental period. Taking into consideration the BCS categories, PBMC isolated from overconditioned cows presented lower IgM secretion compared with thin cows on d 14 and 35 after calving. Furthermore, PBMC isolated from overconditioned cows secreted less IFN-gamma compared with thin and medium cows on d 7 before calving. The DNA synthesis of PBMC stimulated with the 3 mitogens did not differ between the 3 categories of cows. In conclusion, immunodepression occurring in cows around calving would be particularly evident in overconditioned cows.

Animals↗
PubMed2004

Maternal and fetal hypothalamo-pituitary-adrenal axis: different response depends upon the mode of parturition.

OBJECTIVES: The changes in corticotropin releasing hormone (CRH), adrenocorticotropin hormone (ACTH), cortisol and dehydroepiandrosterone (DHEA) in maternal and fetal plasma were estimated in two group of women undergoing labour after oxytocin induction, or elective cesarean section to correlate changes in maternal and fetal HPA axis to the different stressor conditions. MATERIALS AND METHODS: Blood was sampled from a maternal peripheral vein two days before labour, during the second stage of labour and on the second postnatal day, and also from umbilical vessels just after delivery. Hormone concentrations were measured by RIA and ELSA methods. The maternal plasma CRH concentration before and after labour was similar in both studied groups. RESULTS: Plasma CRH levels measured before labour in both groups were similar, but during labour after oxytocin infusion declined, and was in group of women with elective cesarean section rose, after the delivery there was no difference between groups. The plasma ACTH prior to the delivery was at the same level in all subjects, during the third stage of labour ACTH rose in the both groups, but was statistically higher in group with oxytocin infusion. The concentrations of cortisol before delivery was similar in both groups, then rose to the same level during the delivery and then declined to the level observed before delivery. The DHEA concentration was similar in both groups, did not change during the labour, there was no difference between its level in the umbilical vein and artery. In the group with oxytocin-induction there was no correlation between maternal CRH and ACTH or cortisol concentration, but such a correlation occurred in the group with elective cesarean section. The concentration of ACTH and DHEA in umbilical artery was similar in both groups but the concentrations of CRH and cortisol in umbilical artery in group of newborns delivered after elective cesarean section were statistically higher. CONCLUSION: The activity of the mother's HPA axis is partially inhibited rather by psychological stressors, than events connected with mode of parturition. The newborn's HPA axis responds in a specific way to mother's HPA-axis. The communication between mother's and newborn's HPA is possibly related to many other factors than placental CRH and ACTH. It is necessary to consider effects of central CRH and ACTH on the fine-tune regulation of HPA axis in the late pregnancy and parturition, not detectable due to the high levels of placental hormones.

Adrenocorticotropic Hormone↗
PubMed1977

The influence of the fetal hypothalamus and pituitary on the onset and course of parturition.

The possibility that the fetal brain or pituitary either initiates parturition or influences the course of labour was studied in human and rat. The results when corticotropin or neurohypophysial hormones were injected directly into human anencephalic fetuses in utero, and data obtained from 147 clinical records of such fetuses, seemed to show that the fetal brain does not trigger the onset of parturition. On the other hand, the course of labour was seriously protracted in anencephalic fetuses. Gestation length of brain-aspirated rat fetuses was not significantly longer than in sham-operated controls. However, the course of labour was protracted in the brain-aspirated fetuses. A similarly protracted expulsion pattern was observed in Brattleboro rats homozygous for a hypothalamic form of diabetes insipidus. These data all pointed to the likelihood that fetal neurohypophysial hormones stimulate the course of labour. Neither oxytocin nor vasopressin could be demonstrated in the rat fetus on the last day of pregnancy, when specific immunofluorescence was used. However, a closely related compound was found that was identified as most probably being vasotocin. The hypothesis is put forward that this fetal hormone normally stimulates the course of labour.

Anencephaly↗
PubMed2003

Maternal experience influences the establishment of visual/auditory, but not olfactory recognition of the newborn lamb by ewes at parturition.

Maternal behavior in sheep is characterized by the rapid establishment of individual recognition of the lamb through the use of different sensory modalities. Olfactory recognition mediates acceptance at suckling whereas visual/auditory cues are involved in recognition from a distance. This study investigates (a) the timing of both types of recognition and (b) whether they can be influenced by maternal experience. Olfactory recognition was assessed at lambing, 30 min, 1, 2, or 4 hr postpartum by presenting successively an alien and the familiar lamb. Recognition at a distance was assessed at 6, 8, and 12 hr postpartum by using a two-choice test between the familiar and an alien lamb. A majority (33/51) of ewes showed selectivity at suckling as early as 30 min after parturition, and no differences due to maternal experience were observed. By contrast, in the two-choice recognition test, multiparous ewes showed a preference for their familiar lamb at 6 hr whereas primiparous mothers did so only after 24 hr of mother-young contact: The performance of biparous mothers was intermediate. Thus, both types of recognition can be rapidly established after parturition, and maternal experience has a differential effect on the dynamics of these learning processes.

Animals↗
PubMed1992

Changes in annexin (lipocortin) content in human amnion and chorion at parturition.

Arachidonic acid is mobilized from fetal membrane phospholipids at parturition leading to increased production of oxytocic prostaglandins which may initiate or maintain myometrial contractions. Phospholipid mobilization requires activation of phospholipase A2 or C, both of which require calcium for activity. The annexins (lipocortins) are a superfamily of proteins which bind to calcium and phospholipids and thereby may alter phospholipase activity through two mechanisms: modulation of intracellular free Ca2+ concentrations or regulation of the accessibility of phospholipids to hydrolyzing enzymes. Using Western immunoblotting with monospecific polyclonal antibodies, annexins I-VI were identified in human amnion and chorion/decidua at term in tissues obtained from patients in labor or not in labor. Each annexin was present in two distinct pools: a pool which only associated with the membrane in the presence of calcium (calcium-dependent pool) and a calcium-independent pool that remained membrane bound in the presence of calcium chelators. Annexin I was present as two species, resolving at 36 kDa and 68 kDa. The total concentration of annexin I in both amnion and chorion/decidua was significantly decreased with labor, while the total concentration of annexin V in chorion significantly increased with labor. The size of individual pools of annexins also changed with labor: the calcium-dependent pool of annexins I and II in both amnion and chorion significantly decreased; the calcium-dependent pool of annexin V increased in chorion; and calcium-independent pools of annexin I in amnion and annexins I, II, and V in chorion significantly decreased with labor. The decrease in total annexin I concentration with labor in amnion reflects a substantial decrease (80-90%) in the pool tightly bound to the membrane in a calcium-independent manner. This striking change distinguishes annexin I as a potential candidate inhibitor which is specifically downregulated at parturition, potentially leading to increased access of phospholipases to substrate phospholipids and increased prostaglandin production at labor.

Amnion↗
PubMed1993

Nitric oxide synthase activity in the pregnant uterus decreases at parturition.

The mechanisms that mediate changes in uterine activity from a quiescent state during pregnancy to active labor at parturition are unknown. Nitric oxide (NO), a potent mediator of smooth muscle relaxation, and its presence in the uterus is the subject of this report. Nitric oxide synthase (NOS) activity was demonstrated in nerves, blood vessels and decidua of gravid rat uterus by the NADPH-diaphorase staining method. Uterine tissue fixed during labor demonstrated markedly less NOS. Quantitation of NOS activity in subcellular fractions of pregnant and laboring uterus revealed its presence in both the cytosolic and the membranous compartments of uterine homogenates. In both cellular subfractions the enzyme activity decreased significantly from pregnancy to term. We conclude NOS is present in multiple structures within the uterus. Its presence in two cellular compartments suggests more than one form of NOS may be present in the uterus. Reduction in NOS activity at parturition suggests NO may contribute to the maintenance of uterine contractile quiescence during gestation.

Amino Acid Oxidoreductases↗
PubMed2001

Possible involvement of p38 mitogen-activated protein kinase in decidual function in parturition.

We designed the present study to elucidate the molecular mechanism for parturition, focusing on p38 mitogen-activated protein kinase (p38). The kinase activity of p38 in mouse uterus was gestation stage-dependent, and was markedly increased on day 19 of gestation and during labor. Immunohistochemical examination with anti-phospho p38 antibody revealed that activated p38 was predominantly localized in decidual stromal cells stained with anti-prolactin antibody. In human primary cultured decidual cells, a p38 inhibitor, SB202190, significantly inhibited both prostaglandin F(2alpha) production and COX-2 expression induced by stimulation with IL-1beta. These results suggest that the p38 signaling pathway is involved in decidual function at the late stage of gestation and may contribute to parturition.

Animals↗
PubMed2002

Apoptosis and related proteins during parturition in prostaglandin F receptor-deficient mice.

This study investigated whether apoptosis and related proteins are involved in parturition by comparative observation of FP-deficient mice without labor and wild type mice with vaginal delivery. We examined the expression of apoptosis, Fas, FasL, active caspase-3 and bcl-2 proteins in the amnion, placenta and decidua. DNA laddering in the amnion, placenta and decidua tissue did not significantly differ between FP-deficient and wild type mice on day 18 of pregnancy. Similar TUNEL staining results were found in all tissues of FP-deficient mice compared with those of wild type mice. A higher intensity of apoptotic cells was found in the decidua basalis. The index of TUNEL-positive cells were not significantly different in the amnion, placenta and decidua of FP-deficient mice compared with that of wild type mice on day 18 of pregnancy. Specific bands for Fas were clearly observed in the amnion, placenta and decidua tissue. FasL specific bands were observed in the placenta and decidua, but a few in amnion tissue. A great number of active caspase-3 specific bands were detected in decidua, while a few such bands were detected in the placenta and few bands in the amniotic tissue. Bands for bcl-2 were detected in the amnion, placenta and decidua tissue. The weakest band was in decidual tissue. Fas, FasL, active caspase-3, and bcl-2 specific bands did not show any significant differences between the two groups. These findings demonstrate that apoptosis, Fas, FasL, caspase-3, and Bcl-2 occur in mouse term placenta that is not involved in parturition.

Amnion↗
PubMed1993

Effects of the bisphosphonate, alendronate, on parturition in the rat.

Alendronate is a bisphosphonate which inhibits bone resorption. In female fertility studies in rats, dosages of 10 and 15 mg/kg/day produced physical signs of toxicity at parturition, including tremors, dystocia, and death in the dams and these were associated with neonatal deaths. These effects were associated with hypocalcemia in the dams but the fetuses were normocalcemic. There was no one critical period of treatment during gestation for these effects; they were instead proportional to length of treatment. Neonatal deaths were due to protracted deliveries rather than a direct effect of alendronate on the pups. Intravenous calcium supplementation (9.3 mg/dam) prevented the above-described adverse effects on dams and pups. In rats, fetal skeletal ossification is at its greatest rate in late gestation, and during this period free calcium is preferentially transported to the fetal compartment. The females meet this increased demand by calcium mobilization via increased bone resorption. We conclude that the maternotoxicity of alendronate in rats is due to the designed pharmacologic activity of this bisphosphonate; the drug prevents bone resorption and thereby denies the dam an important source of calcium at a time when fetal demand for this mineral is at its peak. The alendronate-induced hypocalcemia adversely affects parturition because uterine muscle contraction is a calcium-dependent process.

Alendronate↗
PubMed1984

Involution and regeneration of the endometrium following parturition in the ewe.

Involution and regeneration of the endometrium after parturition in the ewe, were studied by light- and electron microscopy. The luminal epithelium in intercaruncular regions of the endometrium remained intact at all stages, but degeneration and death of many glandular epithelial cells were observed on the day after parturition. Glandular regeneration had commenced by 8 d post partum, and the glands were substantially regenerated by 15 d. Caruncular epithelial cells on the maternal side of the placentomes, between the bases of the maternal septa, persisted during the period of degeneration of the foetal and maternal tissues of the placentomes. Epithelial cells from this source contributed to the regeneration of the caruncular epithelium following shedding of plaques of degenerate placental tissue from the caruncles, which commenced after 8 d and was completed before 31 d. Thus, ingrowth of epithelium from the edges of the caruncles, as previously proposed, was not the sole source of new caruncular epithelium. The additional source of regenerating epithelium identified here may account for the rapidity with which epithelium appears in the centres of some caruncles, several millimetres in diameter, during endometrial regeneration. However, in some caruncles, regeneration of the epithelium was not completed until after 31 d post partum.

Animals↗
PubMed1988

Mammary lipoprotein lipase in plasma of cows after parturition or prolactin infusion.

Plasma lipase activity from the mammary vein and a tail blood vessel was measured in periparturient Holstein cows treated in one of three ways: control, CB154 (2-Br-alpha-ergocryptin) or CB154 plus prolactin. CB154 administration decreased basal serum prolactin concentration by 80% and blocked the normal parturient increase of serum prolactin. In CB154 plus prolactin-treated cows, prolactin was infused continuously for six days starting five and eight days prepartum. Plasma lipase activity was not detectable up to 26 hr prepartum in control and CB154-treated cows or before the start of prolactin infusion in CB154 plus prolactin-treated cows. After two hr prepartum, plasma lipase activity was detected in all treatments. In CB154 plus prolactin-treated cows, plasma lipase activity was detected in the presence of high concentrations of serum progesterone four days after the start of prolactin infusion and at least two days before parturition. Plasma lipase activity was four times greater in the mammary vein than in the tail vessel at sampling times at which activity was detected in both vessels. We propose the difference between plasma lipase activity from the mammary vein and tail vessel is due to release of lipoprotein lipase from the mammary gland into blood, and this activity can be induced prepartum by prolactin or at parturition even if the parturient increase in prolactin is suppressed.

Animals↗
PubMed2004

Non-offspring nursing by a nulliparous pregnant female just before first parturition in free-ranging Japanese macaques.

A nulliparous pregnant Japanese macaque, Macaca fuscata, suckled her 1-year-old sister 44 days before her own parturition. Other Japanese macaque yearlings did not hold the nipples of this nulliparous female in their mouths. Although this non-offspring nursing before first parturition did not improve the rate of milk secretion, the nulliparous female may have improved her indirect fitness and her suckling behavior.

Animals↗
PubMed1976

Changes in evolution of free epinephrine, norepinephrine, and vanillylmandelic acid in the urine of rabbits during late pregnancy and parturition.

The present study describes evolutionary changes in urinary excretion of epinephrine, norepinephrine, and vanillylmandelic acid during pregnancy and parturition. Both the catecholamines and their metabolite were determined in 24 hour urine samples of rabbits from day 13 of pregnancy. During 13 and 28 days of gestation, urinary excretion of epinephrine was at its lowest value. As compared to normal rabbits, an increase of 135 per cent in epinephrine excretion during day 30 of pregnancy was observed. Norepinephrine excretion reached its maximum level during day 13 but constant declines occurred afterward. Contrary to epinephine, urinary excretion of norepinephrine was at the highest value days 23 and 30 of pregnancy. After day 19 vanillylmandelic acid declined continuously up to day 30. During parturition vanillymandelic acid and norepinephrine excretion returned to the control values but epinephrine remained slightly higher. These alterations in catecholamine urinary excretion have been suggested as a consequence of modified endocrine and sympathetic activity.

Animals↗
PubMed1978

The relationship of changes in mammary blood flow and plasma progesterone at the time of parturition in the ewe.

Previous studies indicate that there is a fall in maternal plasma progesterone and a marked increase in mammary blood flow (MBF) at the time of parturition in ewes. In this experiment the role of progesterone as a cause of this increase in MBF was investigated. Progesterone was infused (9.9 mcg. per minute) into a branch of the mammary artery in five sheep during the induction of premature labor by fetal dexamethasone infusion (1 mg. per 24 hours) to prevent the normal fall in concentration of local mammary artery progesterone. Five ewes used as controls received a mammary artery infusion of cholesterol (9.9 mcg. per minute). In the cholesterol-infused group MBF increased significantly from baseline after 13 +/- 4 hours (mean +/- standard error) to a peak flow of 235 +/- 9 ml. per minute. In the group receiving the progesterone the increase in MBF was delayed to 35 +/- 7 hours, reaching only 161 +/- 22 ml. per minute. These results were significantly different from control group results (p less than 0.01). This study suggests that the fall in maternal plasma progesterone which occurs at the time of parturition may play a role in the increase in MBF that occurs prior to the onset of labor, delivery, and lactogenesis.

Animals↗
PubMed1982

Serum nickel concentration in women during pregnancy, during parturition, and post partum.

Concentrations of nickel (Ni) were measured by atomic absorption spectrophotometry in serum collected from 67 women divided into five groups: (1) healthy control subjects; (2) third-trimester pregnancy (32 to 36 weeks); (3) parturition; (4) post partum 1 (5 minutes); (5) post partum II (60 minutes). In the pregnant group, the serum level of Ni was lower by 60% than that in either the control or parturient group. A significant twenty-fold elevation in the concentration of nickel was observed immediately after delivery of the infant but before delivery of the placenta. Sixty minutes after parturition, the serum concentration of Ni was again similar to the control value. The possible physiologic significance of transient hypernickelemia in the advanced stage of human labor may be related to the support of placental separation and/or to the prevention of atonic bleeding.

Adolescent↗