Normal Pregnancy Levels Research Articles

Serum uric acid levels in normal pregnancy.

Sixty-four patients were assessed throughout pregnancy to determine normal serum uric acid levels (mean +/- 2SD). Serum uric acid levels increased significantly from early pregnancy levels of 0.13-0.33 nmol/L to levels of 0.18-0.45 mmol/L at full-term (p less than 0.005). Factors implicated in uric acid homeostasis contributing to these changes are discussed.

Predictive value of a single serum pregnancy associated plasma protein-A or progesterone in the diagnosis of abnormal pregnancy

The value of a single measurement of serum levels of pregnancy associated plasma protein-A (PAPP-A) or progesterone (P4) in predicting abnormal gestations was assessed in 65 patients. P4 was greater than 20 ng/ml (mean +/- SEM 61.2 +/- 6.6 ng/ml, range 22.4-100.0 ng/ml) in all patients with normal intrauterine pregnancies (n = 21), and greater than 20 ng/ml (mean +/- SEM 8.5 +/- 3.9 ng/ml, range 0.1-68.8 ng/ml) in 16 out of 17 patients destined to abort spontaneously. Patients with ectopic gestations (n = 27) exhibited P4 values less than 20 ng/ml (mean +/- SEM 6.4 +/- 1.2 ng/ml, range 0.1-17.2 ng/ml). P4 levels in normal pregnancies were significantly higher (P = 0.001) than those of abnormal gestations. PAPP-A levels ranged from undetectable to 6448 mIU/ml in normal gestations. In 42 out of 44 abnormal pregnancies levels of PAPP-A were less than 100 mIU/ml, as were 7 out of 14 normal intrauterine pregnancies of less than 7 weeks gestational age. No ectopic demonstrated a value of PAPP-A greater than 50 mIU/ml and in 23 out of 27 ectopics, levels were undetectable. However, PAPP-A was less specific than P4 in correctly discriminating normal from abnormal gestations and exhibited lower positive and negative predictive values. It can be concluded therefore that a single PAPP-A measurement is of limited value in discerning normal from abnormal pregnancy prior to 8 weeks gestation. However, a single serum P4 is highly accurate and specific in detecting abnormal pregnancy, regardless of gestational age.

Carboxyhemoglobin levels in normal pregnancy and preeclempsia

Carboxyhemoglobin levels in normal pregnancy and preeclempsia

Serum complement levels in normal pregnancy and pregnancy-induced hypertension

Serum complement assay (CH50) was carried out in urban low-income women belonging to the following groups: (i) non-pregnant and non-lactating women; (ii) pregnant women in different periods of gestation; (iii) women suffering from pregnancy-induced hypertension. Serum CH50 titers showed significant increase in the second and third trimester pregnancies as compared to non-pregnant, non-lactating women. There were no differences in CH50 levels between women suffering from pregnancy-induced hypertension and those with normal pregnancy of comparable period of gestation. Nutritional status did not seem to have any influence on complement titers.

Glycated albumin and glycated hemoglobin levels in normal pregnancy.

Glycated albumin levels showed a progressive increase during normal pregnancy. The mean values (mole hexose/mole protein) were 1.68 +/- 0.27 (n = 15) in nonpregnant women, 1.83 +/- 0.21 (n = 11) in first trimester, 2.00 +/- 0.41 (n = 13) in second trimester, and 2.42 +/- 0.49 (n = 15) in third trimester. Glycated hemoglobin levels indicated a biphase pattern with low values at midpregnancy (controls 0.29 +/- 0.05, first trimester 0.30 +/- 0.04, second trimester 0.27 +/- 0.05, and third trimester 0.33 +/- 0.04). The data suggest that glycated albumin reflects the decreased glucose tolerance in pregnancy better that glycated hemoglobin levels. The reasons for the differing pattern of the two glycated proteins are discussed.

Placental protein 21. Localization in human placenta and concentrations in the body fluids of men and nonpregnant and pregnant women.

The immunohistochemical localization of placental protein 21 (PP21) was marked in the syncytial brush border and basal membrane during the 1st and 2nd trimesters of pregnancy and also in the chorionic epithelial brush border and basement membrane at term. A weaker stain was found in the cell membranes of amniotic epithelial and chorionic trophoblast cells. Neither heparin nor changes in temperature significantly influenced PP21 concentration. Relatively high serum PP21 concentrations were measured during the follicular and luteal phases in healthy nonpregnant women and in healthy men whose seminal plasma also showed a high PP21 concentration. Serum PP21 levels in normal pregnancy rose from a median of 29.1 ng/ml at 6-7 weeks of gestation to 82.0 ng/ml at 36-37 weeks of gestation. Although maternal urine showed low PP21 levels during pregnancy, amniotic fluid PP21 levels were higher at 7-21 weeks of gestation than at term. Cord blood sera showed almost the same PP21 concentration as maternal sera, but retroplacental blood showed much higher levels. Maternal serum PP21 levels in hydatidiform mole patients did not differ from the normal pregnancy range, although their molar vesicular fluids contained higher PP21 concentrations. These results suggest an extraplacental source for PP21.

AMNIOTIC FLUID (AF) ARGINIE-VASOPRESSIN (AVP) CONCENTRATIONS IN NORMAL PREGNANCIES AND INTRAUTERINE GROWTH RETARDATION (IOGR)

AVP is released by the fetus but only in response to osmotic, but also to nonosmotic stimuli such as hypoxia. Once released, AVP is excreted via fetal urine into AF where it has a long half life compared to plasma (ca 8 hours). Tbe hypothesis of the present study therefore was, that fetal hypoxia might be diagnosed by elevated AF-AVP levels. As a model we used IUGR fetuses which are known to he hypoxic. 25 infants entered the study because IUGR was suspected by ultrasound. The normal AF-AVP levls as control values were determined in 93 uncomplicated pregnancies where amniocentesis was performed for other reasons (L/S ratio determinations, genetic reasons, rh-sensitized pregnancies with rh-negative fetuses). HPL values were measured by RIA as were Af-AVP values. Results: The mean AF-AVP levels in normal pregnancies from 16 to 41 weeks of gestation was 2.37 ± 1.16 SD pg/ml. There was no significant difference with different gestational age. At birth 7 of the 25 infants hod normal birth weight and 18 actually had IUGR. There was a significant correlation between the degree of IUGR and AF-AVP levels (r=.59, p<0.05). The correlation between the HPL values and the degree of IUGR was the same as for AF-AVP values (r=.59, p<0.05). Discussion: 1) To our knowledge we report AF-AVP values for the greatest group of normal pregnancies yet published. 2) AF-AVP levels are elevated in IUGR. Ihe levels dependent on the severity of IUGR. These data support the usefulness of AF-AVP determinations for the diagnosis of fetal wellbeing as demonstrated in a previous study in rh-erythroblastosis (1). The elevated AF-AVP levels in IUCR might explain findings of diminished urine production of these fetuses (2). (1)Stegner et al. Acta Endocrinol 112,267,1986 (2)Wallenburg et al. J Perinot Med 6,233,1977

Plasma fibronectin levels in normal pregnancy and pre-eclampsia: A preliminary report

Fibronectin, a major component of the extracellular matrix and basement membranes throughout the body, is thought to maintain the integrity of both the reticulo-endothelial system and microvasculature. In this study, plasma fibronectin levels were assayed by nephelometry in nine pre-eclamptic gravid women, nine normotensive gravid women and ten non-gravid women. The mean plasma fibronectin level (±S.E.M.) in pre-eclamptic gravidas (1687 ± 101 μg/ml) is significantly higher than that of either normotensive gravidae (1129 ± 99 μg/ml) or non-gravid women (897 ± 60 μg/ml). Although the mechanism for elevated levels of plasma fibronectin in patients with pre-eclampsia is not clear, it may serve as an early biochemical marker for this disorder.

Urinary 19-nor-deoxycorticosterone and deoxycorticosterone in hypertensive disease of pregnancy.

Normal pregnancy and pre-eclampsia are associated with water and sodium retention. Therefore various mineralocorticoids have been evaluated in normal and abnormal pregnancies. This study reports the urinary free 19-nor-deoxycorticosterone (19-nor-DOC) and deoxycorticosterone (DOC) levels in normal pregnancy and in patients with pregnancy-induced hypertension. Levels of 19-nor-DOC and DOC were not significantly different between normal patients in the third trimester and women with pregnancy-induced hypertension at a comparable gestational age. The urinary excretion of 19-nor-DOC in pregnancy was noted to be significantly lower than that previously reported in normal male volunteers. There was a positive correlation between 19-nor-DOC excretion and increasing gestational age. These data are compatible with the view that 19-nor-DOC may not play a role in pregnancy-induced hypertension. However, a larger study of primigravid women, with and without, pre-eclampsia is needed to confirm this finding.

Angiotensin converting enzyme activity in hypertensive pregnancy.

Recent investigations suggest angiotensin converting enzyme (ACE) activity is generally decreased in normotensive pregnancy, but less is known about the level of activity of this enzyme in hypertensive pregnant subjects. The primary source of ACE is vascular endothelium and it can be measured in serum or plasma. In a preliminary investigation, we measured and compared diastolic blood pressure and serum ACE activity in 14 uncomplicated pregnant subjects during the third trimester, and in 16 subjects of similar gestation duration hospitalized with pregnancy-induced hypertension PIH. No patient had a positive history for, or evidence of, pulmonary or other metabolic disease. Compared with levels in normal pregnancy, serum ACE activity was found to be significantly elevated in PIH. In this study, this increase was not due to differences between the groups in maternal chronologic age or gestational duration. Further studies are necessary to determine if the increase in ACE activity precedes or follows development of clinically apparent PIH. If the former is the case, ACE activity might be a useful indicator of risk for PIH.

Uteroplacental unit as a source of elevated circulating prorenin levels in normal pregnancy

Circulating levels of inactive renin, that is, prorenin, are increased in normal pregnant women. To determine whether the uteroplacental unit secretes prorenin into the maternal circulation, we measured enzymatically active and inactive renin in plasma simultaneously obtained from the radial artery and uterine vein of 12 normotensive, nonlaboring patients undergoing elective cesarean section at term. We also measured these forms of renin in the umbilical arterial and venous blood of these patients. Our data reveal that (1) the levels of inactive renin in both arterial and uterine venous blood of normal pregnant women are significantly higher than in peripheral venous blood of nonpregnant, normotensive control subjects; (2) normotensive term patients have a ratio of plasma inactive to active renin of 9:1 in contrast to the 1:1 ratio in normotensive nonpregnant subjects; (3) there is a significant uterine arteriovenous difference of prorenin (66.2 ± 24.4 ng/ml/hr, p < 0.05) but not of active renin (1.8 ± 1.5 ng/ml/hr, not significant). These results suggest that the uteroplacental unit contributes to the elevated prorenin levels at term pregnancy.

Fibrinolytic Activity and Protein C in Preeclampsia

Various parameters of the fibrinolytic system and antigenic and functional protein C and its inhibitor were studied during normal pregnancy and in patients with preeclampsia. The fast acting tissue-type plasminogen activator inhibitor level was found to increase progressively during normal pregnancy. This increase was more evident in cases of severe preeclampsia (p less than 0.05). No variations were observed in protein C levels in normal pregnancies but a reduction in protein C level was noted in patients with severe preeclampsia (p less than 0.01). In preeclampsia, the protein C inhibitor level was higher than in normal pregnancy; it was also higher in normal pregnancy when compared to the control group.

Amerlex free triiodothyronine and free thyroxine levels in normal pregnancy.

Free triiodothyronine (FT3) and free thyroxine (FT4) were measured in 159 women during normal pregnancy and compared with non-pregnancy reference ranges for these hormones. FT3 values fell from the reference level of 6.34 (SD 1.06) pmol/l to 3.87 (SD 0.54) pmol/l in the 3rd trimester; corresponding figures for FT4 were: reference 16.92 (SD 2.97) pmol/l, 3rd trimester 11.29 (SD 2.01) pmol/l. There were no significant changes in the 1st trimester; 4% and 69% of FT3 results in the 2nd and 3rd trimesters respectively fell below the reference range of mean +/- 2 SD. The corresponding findings for FT4 were 4% and 42%. FT3 correlated reasonably well with total T3 (r = 0.90) and was acceptably precise (within-batch CV 2.1% at 5.6 pmol/l, between-batch CV between 3.1% and 4.7% at six levels).

Factor VIII-related antigen levels in normal pregnancy and puerperium

The changes in serum Factor VIII-related antigen (Factor VIII RAg) levels in normal pregnancy and puerperium in Chinese women were studied by the Laurell ‘rocket’ immunoelectrophoresis. At 6 wk of gestation, the serum Factor VIII RAg levels were already higher than those of non-pregnant women and gradually increased through term pregnancy. Parturition did not have immediate effects on the circulating levels of Factor VIII RAg. The levels of Factor VIII RAg observed during labour and days 1–5 postpartum were similar to those of term pregnancy. By the 6th wk postpartum, the serum Factor VIII RAg declined to basal levels, similar to those of non-pregnant control samples.

Calcium, parathyroid hormone and calcitonin in normal pregnancy and preeclampsia.

Calcium, parathyroid hormone (PTH) and calcitonin (CT) in serum, and the fractional renal excretion of calcium (FECa) were determined in (1) normal pregnant women, (2) patients with preeclampsia, and (3) normal nonpregnant control subjects. Serum calcium, corrected for individual variation in serum protein, was reduced and FECa increased in the normal pregnant group when compared to the nonpregnant control group. In preeclampsia serum calcium did not differ significantly from the normal pregnant group, but FECa was considerably lower and also reduced below the level in the nonpregnant control group. PTH was slightly lower during normal pregnancy than after delivery, but did not deviate significantly from the nonpregnant control group; in preeclampsia PTH did not deviate significantly from the levels in normal pregnancy. CT was the same in the third trimester of pregnancy in both groups. Changes in serum calcium and FECa were not correlated to PTH or CT. It is concluded that both normal pregnancy and preeclampsia are accompanied by considerable alterations in calcium metabolism, that PTH and CT in both groups are mainly unchanged and at nonpregnant level, and that the increase and decrease in renal calcium excretion in normal pregnancy and preeclampsia, respectively, may be attributed to changes in kidney function.

Plasma noradrenaline and adrenaline levels in normal pregnancy and in pregnancy-induced hypertension.

Plasma concentrations of noradrenaline and adrenaline were measured serially during normal pregnancy in 52 women who remained normotensive and in nine who developed pregnancy-induced hypertension but were otherwise normal. There was a significant fall in both noradrenaline (P less than 0.005) and adrenaline (P less than 0.05) levels during normal pregnancy. Throughout pregnancy the mean levels of both catecholamines were lower in the patients who developed pregnancy-induced hypertension than in the normotensive patients. There was no evidence of increased sympathetic nervous system activity in the women who developed pregnancy-induced hypertension.

A radioimmunoassay for pregnancy associated protein, beta 1SP1: levels in pregnancy, trophoblastic and neoplastic disease.

A radioimmunoassay system for the glycoprotein beta 1SP1, one of the pregnancy-associated proteins, has been set up. beta 1SP1 levels in normal pregnancy have been established transversally. Clearance (t1/2) from the circulation postpartum ranged from 1.4 to 1.8 days. Several patients with trophoblastic disease, e.g., mola hydatidosa, choriocarcinoma and embryonic cell carcinoma, were followed longitudinally. Human chorionic gonadotropin (hCG), a highly reliable tumor marker in trophoblastic disease, has been determined concomitantly by radioimmunoassay. In all instances, hCG proved to be a better indicator of the presence of a tumor, because by the time beta 1SP1 became undetectable, hCG could still be detected. Samples from a large multicenter study on trophoblastic disease were studied: out of 100 positive for hCG, beta 1SP1 could be detected in 86; however, out of 21 samples in which hCG was not detectable, 1 was found to be positive for beta 1SP1. In a number of samples from patients with bronchial carcinoma, no beta 1SP1 could be detected.

Prenatal Diagnosis of llβ-Hydroxyiase Deficiency Congenital Adrenal Hyperplasia*

To predict 11beta-hydroxylase deficiency congenital adrenal hyperplasia antenatally, studies were performed in urines and amniotic fluids from 2 pregnant women who had previously given birth to affected infants and whose present pregnancies also resulted in infants with the disease. Urinary tetrahydro-11-deoxycortisol [pregnane-3alpha, 17alpha, 21-triol-20-one (THS)] was abnormally elevated in the first, second, and third trimesters (maximal values, 3.5 and 0.9 mg/24 h, respectively) but was undetectable after delivery in these mothers, in 15 normal pregnancies (10--40 weeks of gestation), and in 6 heterozygote parents. Amniotic fluid levels of THS, tetrahydrocortisol [pregnane-3alpha, 11beta, 17alpha, 21-tetra-o1-20-one (THF)], tetrahydrocortisone [pregnane-3alpha, 17alpha, 21-triol-11, 20-dione (THE)] measured by RIA at 18 weeks of gestation in the first mother and at 40 weeks in the second revealed 12.5- and 8.4-fold increases in THS, respectively, but normal THF and THE levels compared to mean levels in normal pregnancies. The THS to THF plus THE ratio, which was constant throughout pregnancy in 125 normal women (mean +/- SD, 0.63 +/- 0.34) despite the variable levels of these metabolites, was significantly elevated in both patients (4.4 and 3.8, respectively). These studies indicate that prenatal diagnosis of 11beta-hydroxylase deficiency congenital adrenal hyperplasia based on hormonal measurements is feasible.

Comparison of Plasma Volume Levels in Normal Pregnancy Between Two Ethnic Groups in Fiji

Summary: In the normal pregnancy Indian women have a lower plasma volume than Fijian women. Volume studies in the third trimester on the normal pregnancies of 191 Fijian women and 92 Indian women showed that the latter group also had lower red cell volumes and blood volumes. Consequently, both groups showed a similar distribution of haemoglobin concentration. The reduction in plasma volume is not related to parity and the plasma volumes of Indian women did not show the correlation with maternal height of the Fijian women. In view of the higher reported incidence of toxaemia in Indian women, these findings support the concept that a reduction in plasma volume occurs before the onset of clinical signs of toxaemia.Indian women also have a lower plasma volume for a given birth‐weight/ maternal size ratio. There is some evidence that they have smaller babies than Fijian women after allowing for the differences in maternal size but the results are statistically inconclusive.

Comparative study of amniotic fluid and maternal blood serum human placental lactogen in normal and prolonged pregnancies

The levels of human placental lactogen (hPL) were measured in maternal blood and amniotic fluid in normal and prolonged pregnancles. Statistical analysis of the hPL levels showed that values rose in both blood and amniotic fluid, reaching maximum levels between Weeks 34 and 36 (6.70 μg per milliliter in blood serum, 0.85 μg per milliliter in amniotic fluid). Thereafter, there was a decline, a significant fall occuring between Weeks 40 and 42 and in the prolonged pregnancy group (43 weeks and more) (t = 6.9 and p < 0.001 in serum levels; t = 3.9 and p < 0.001 in amniotic fluid levels). There was also a very close correlation (r = 021; p < 0.005) between maternal blood and amniotic fluid hPL levels in normal pregnancies before labor.