Fetal erythropoietin levels in pregnancies complicated by meconium passage: does meconium suggest fetal hypoxia?

OBJECTIVE: We sought to determine whether umbilical cord plasma erythropoietin levels were different in deliveries complicated by meconium passage and to determine whether this response is influenced by gestational age. STUDY DESIGN: Fetal erythropoietin levels were measured in 203 appropriately grown neonates at 37 to 43 weeks of gestation; among those, 70 had passed meconium. RESULTS: Meconium passage in the entire population was associated with elevated fetal erythropoietin levels (68 vs 31 mIU/mL; P <.001). Cord blood gases, pH, base deficit, and PO (2), as well as the 1- and 5-minute Apgar scores, were not different between the meconium and no-meconium groups. Gestational age and birth weights were significantly higher in the meconium group. Stepwise multiple regression analysis with meconium and gestational age used as the independent variables showed both meconium and gestational age to be independently associated with fetal erythropoietin levels (r = 0.356, F = 14.5; meconium, P <.001; gestational age, P <.01). CONCLUSIONS: These results suggest that meconium passage can be associated with chronic fetal hypoxia as demonstrated by elevated fetal erythropoietin levels, independent of gestational age.

Human uterine leiomyomata express higher levels of peroxisome proliferator-activated receptor gamma, retinoid X receptor alpha, and all-trans retinoic acid than myometrium.

Uterine leiomyomata are the main indication for a hysterectomy in the United States and occur in 25% of women >35 years. Because uterine leiomyomata can form when ovariectomized guinea pigs are exposed to estradiol and retinoic acids, we tested whether human leiomyomata had high levels of retinoic acids and related nuclear receptors. Compared with normal human myometrium, leiomyomata had 3- to 5-fold higher levels of peroxisome proliferator-activated receptor gamma (PPARgamma), retinoid X receptor alpha proteins, and all-trans retinoic acid, but only during the follicular phase of the menstrual cycle. 9-cis Retinoic acid was undetectable in either leiomyomata or myometrium. PPARgamma mRNA levels were lower in leiomyomata than myometrium, but only during the luteal phase of the cycle. A PPARgamma agonist, troglitazone, was given to guinea pigs along with estradiol and all-trans retinoic acid and produced the largest leiomyomata seen to date in this model. By contrast, no tumors formed when troglitazone was given alone or with estradiol or when troglitazone was given with estradiol and 9-cis retinoic acid. New therapies for human leiomyomata may emerge by combining antagonists for PPARgamma and retinoid X receptor alpha with selective estrogen receptor modulators.

Modulation of the prostaglandin E receptor: a possible mechanism for infection-induced preterm labor.

OBJECTIVE: To evaluate the modulatory effects of interleukin (IL)-1beta and prostaglandin (PG)E2 on the PGE2 receptor subtype EP1 in amnion cell cultures. METHODS: Amnion cell cultures were incubated in increasing concentrations of (IL)-1beta or PGE2. Cultures were also incubated in high concentrations of IL-1beta and PGE2 in combination. Changes in EP1 receptor levels were evaluated by western and northern blot analysis. Culture fluid PGE2 levels were measured by enzyme-linked immunosorbent assay. RESULTS: EP1 receptor protein levels decreased with increasing levels of PGE2 (r = -0.82, P < .05). EP1 receptor protein (r = 0.95, P < .05), EP1 mRNA (r = 0.95, P < .01), and culture fluid PGE2 levels (P < .01) were all increased after IL-1beta administration. EP1 receptor levels also increased approximately fourfold in response to IL-1beta incubation even in the presence of high agonist (PGE2) concentrations (P < .01). CONCLUSION: The results of this study show that IL-1beta might be involved in infection-induced preterm labor by interfering with the normal regulation of EP1 receptor levels and with the promotion of increased PGE2 production in amnion tissue.

Fetal erythropoietin levels in growth-restricted and appropriately grown neonates with and without abnormal fetal heart rate tracings: a comparison with cord blood gases and Apgar scores.

OBJECTIVE: To determine if umbilical cord plasma erythropoietin (EPO) levels in combination with cord blood gases and Apgar scores can distinguish between subacute and chronic uteroplacental insufficiency. METHODS: A total of 184 neonates delivered between 1993 and 1997 at Tampa General Hospital were studied. Cord plasma EPO levels, cord blood gases, and Apgar scores were determined prospectively and compared in four subgroups that were defined based on the presence or absence of fetal growth restriction (FGR; chronic fetal hypoxia), abnormal fetal heart rate tracings during labor (FHR; subacute/acute fetal hypoxia), or both. RESULTS: Both growth-restricted and appropriately grown newborns with abnormal intrapartum FHR tracing had elevated umbilical cord plasma EPO (183.5 and 135.2 mIU/ml, respectively; normal = 20.7 mIU/ml) and base deficit, whereas pH, Po2, and 1-minute and 5-minute Apgar scores were significantly lower, compared with appropriately grown newborns with a normal intrapartum course. Among newborns with normal heart rate tracings and FGR, the mean plasma EPO levels were elevated (89.5 mIU/ml), whereas the other parameters were not different from normal. CONCLUSION: Our findings suggest that, although cord blood gases and Apgar scores may reflect subacute and acute events, they are not good predictors of chronic uteroplacental insufficiency. The supplemental use of umbilical cord plasma EPO levels may improve our ability to identify chronic uteroplacental insufficiency.

Effects of raloxifene in a guinea pig model for leiomyomas.

OBJECTIVE: Chronic exposure of oophorectomized guinea pigs to 17beta-estradiol causes leiomyoma formation. Our aims were to determine whether these leiomyomas can become estradiol independent after exposure to estradiol and if raloxifene inhibits leiomyoma growth when given concomitantly with estradiol. STUDY DESIGN: To induce leiomyoma development, 6 oophorectomized animals received two estradiol implants for 140 days. Next, the estradiol implants were replaced with empty implants in 3 animals, whereas the other 3 received 2 new estradiol implants and raloxifene given per os 10 mg/kg per day for 60 days. Tumor size was monitored biweekly by ultrasonography. RESULTS: On estradiol removal, abdominal wall leiomyomas regressed within 15 to 30 days; when estradiol implants were reintroduced, leiomyomas redeveloped. Within 30 days on raloxifene, all abdominal leiomyomas (n = 9) regressed as determined by ultrasonography and verified at laparotomy. Serum raloxifene and estradiol levels were 432 +/- 46 pg/mL and 78 +/- 13 pg/mL (mean +/- SEM, n = 3), respectively, after 60 days of treatment. CONCLUSIONS: Leiomyomas did not become estradiol independent, even after long exposure to estradiol; ultrasonography allowed frequent, noninvasive assessment of leiomyoma size, and raloxifene rapidly regressed leiomyomas in this animal model.

Elevated umbilical cord plasma erythropoietin levels in prolonged pregnancies.

OBJECTIVE: To determine if umbilical cord plasma erythropoietin levels are elevated in pregnancies that continue beyond their expected date for delivery. METHODS: Erythropoietin was measured using an enzyme-linked immunosorbent assay in 124 appropriately grown newborns delivered from 37-43 weeks' gestation. Each woman had an uncomplicated labor and delivery course without evidence of fetal stress or meconium. The comparison was made between pregnancies ending at 37-40 weeks' gestation and those at 41-43 weeks' gestation. RESULTS: There was no difference between the two groups in cord blood gases or Apgar scores at 1 and 5 minutes. Cord plasma erythropoietin levels were significantly higher in pregnancies delivered after 41 completed weeks' gestation (41 or more weeks: 48.0+/-7.1 mIU/mL, n=45 versus 37-40 weeks: 26.1+/-4.2 mIU/mL, n=79, P < .001). When compared with pregnancies delivered between 37 and 40 weeks, erythropoietin levels were significantly elevated in pregnancies delivered at either 41, 42, or 43 weeks' gestation. CONCLUSION: In pregnancies reaching 41 weeks and beyond, cord plasma erythropoietin levels are significantly increased, indicating altered fetal oxygenation in some of these pregnancies. These results support the current practice of close fetal surveillance of prolonged pregnancies.

Umbilical cord plasma erythropoietin levels in pregnancies complicated by maternal smoking.

OBJECTIVE: Our goal was to determine whether maternal smoking was associated with elevated umbilical cord erythropoietin, a marker for chronic hypoxia. STUDY DESIGN: Plasma erythropoietin levels were measured in umbilical cord plasma of 222 newborns. There were 48 mothers who smoked and 174 nonsmokers. RESULTS: When all pregnancies were included, mean cord plasma erythropoietin levels were significantly higher in the smokers (78.0 +/- 15.3 mIU/ml) compared with the nonsmoking group (35.2 +/- 4.0 mIU/ml; p < 0.005). Regression analysis showed a significant positive correlation between the number of cigarettes smoked per day and cord plasma erythropoietin levels (r = 0.26, p < 0.0001). Smoking was associated with a significantly elevated risk (relative risk = 2.6, 95% confidence interval 1.7 to 10.9, p < 0.005) of fetal growth restriction. When pregnancies with fetal growth restriction were excluded from the analysis, the difference between the two groups remained significant (smokers 81.3 +/- 18.6, n = 38; nonsmokers 24.3 +/- 1.4, n = 164; p < 0.03). CONCLUSIONS: These results illustrate that smoking during pregnancy is associated with fetal growth restriction and significantly elevated umbilical cord erythropoietin levels.

Tumor necrosis factor-alpha upregulates the prostaglandin E2 EP1 receptor subtype and the cyclooxygenase-2 isoform in cultured amnion WISH cells.

Recent studies have demonstrated a strong correlation between infection and preterm labor. Preterm delivery is also associated with high levels of cytokines and prostaglandins in amniotic fluid. The purpose of this study was to investigate the effect of tumor necrosis factor-alpha (TNF-alpha) on the levels of cyclooxygenase, prostaglandin E2 production (PGE2), and expression of the PGE2 receptor subtype EP1 in amnion WISH cell culture. Amnion WISH cell cultures were incubated in increasing concentrations of TNF-alpha (0-50 ng/ml). Changes in cyclooxygenase and EP1 receptor proteins were evaluated by Western blot analysis. Changes in EP1 mRNA were evaluated by Northern blot, and culture fluid concentrations of PGE2 were estimated by enzyme immunoassay (EIA). EP1 protein (p<0.01), EP1 mRNA (p<0.05), cyclooxygenase-2 (COX-2) protein (p<0.001), and PGE2 concentrations (p<0.01) all increased with increasing concentrations of TNF-alpha. Changes in COX-1 protein were not observed following TNF-alpha-incubation. The results suggest that TNF-alpha may play a role in infection-induced preterm labor by its pleiotropic ability to simultaneously stimulate COX-2 activity, PGE2 concentrations, and PGE2 EP1 receptor levels in human amnion.

Are maternal diabetes and preeclampsia independent simulators of fetal erythropoietin production?

To determine if diabetes and preeclampsia are independent stimulators of erythropoietin, distinct from hypoxia, we measured umbilical cord plasma erythropoietin in 239 deliveries from 24 to 40 weeks of gestation. Mean plasma erythropoietin levels were not different between normal, diabetic, and preeclamptic women when all deliveries were analyzed. When infants with suspected intrauterine hypoxia were excluded, the mean erythropoietin level was considerably lower within all three groups but there was no difference among the groups. In suspected hypoxia, the mean fetal erythropoietin was elevated, but there was no difference between control, diabetic, or preeclamptic pregnancies. These results provide further support that hypoxia remains the only known stimulator of erythropoietin production in the fetus.

The effect of interleukin-1 beta and interleukin-4 on the expression of prostaglandin receptors EP1 and EP3 in amnion WISH cells.

PROBLEM: Although prostaglandin E2 (PGE2) is believed to modulate biochemical and immunological events leading to parturition, the role of prostaglandin E receptors during labor has not been investigated. METHOD OF STUDY: Amnion WISH cells were incubated in media containing increasing concentrations of either interleukin-1 beta (IL-1 beta) or IL-4. Increased EP1 and EP3 protein expression was determined by Western blot analysis with peptide-specific antibodies. Concomitant measurements of culture media PGE2 were made by an enzyme immunoassay. RESULTS: Incubation of WISH cells with IL-1 beta or IL-4 caused a two- to three-fold increase in EP1 protein levels. IL-1 beta and IL-4 also caused six- and two-fold increases, respectively, in culture fluid PGE2 concentrations. IL-1 beta or IL-4 had no effect on EP3 protein levels. CONCLUSIONS: Based on these results, it is proposed that IL-1 beta and IL-4 may be involved in the initiation and promotion of labor by inducing EP1 levels and PGE2 production in amnion.

Umbilical plasma erythropoietin correlations with blood gases and gestational age in appropriately grown infants.

Erythropoietin (EPO) levels were measured using an ELISA method in umbilical cord plasma from 68 appropriately grown neonates at 27 to 43 weeks of gestation (EGA). A consistent but small (5%) difference was found between the EPO levels in the umbilical artery (Ua), 21.0 +/- 2.5 mlU/mL (mean +/- SEM), and umbilical vein (Uv), 22.0 +/- 2.7 mlU/mL (p < 0.02, n = 30). Significant inverse correlations were found between Ua EPO levels and pO2 (r = -0.44, p < 0.002), pH (r = -0.68, p < 0.0001), as well as base deficit (r = -0.56, p < 0.0001). A significant correlation was found between EGA and Ua EPO from 27 to 43 weeks of gestation (r = 0.45, p < 0.001, n = 68). One and 5 minute Apgar scores did not correlate with EPO. These findings indicate that EPO correlates strongly with cord gas parameters and thus may serve as a clinically useful marker for both subacute fetal distress and chronic uteroplacental insufficiency.

Estrogen-induced guinea pig model for uterine leiomyomas: do the ovaries protect?

A guinea pig model was used to study the hormonal control of uterine leiomyomas. Twenty female guinea pigs were divided into four groups--young, old, ovariectomized (OVX), and non-OVX animals--and were given two estradiol-17 beta (E2) silastic implants each for 3-10 mo; another four older OVX animals served as controls and received empty implants. After 3 mo, 100% (8 of 8) of the OVX animals, but none of the OVX controls, developed tumors, mainly on the uterine serosa and the abdominal wall. Electron microscopy and desmin immunostaining demonstrated that the tumors were leiomyomas. In E2-treated animals, E2 levels in serum, leiomyomas, or leiomyoma-free uterine segments rose significantly while serum progesterone (P4) was negligible. Surprisingly, only 8% (1 of 12) of the non-OVX animals developed a tumor. This apparent "ovarian protection" was transient: after 6-9 mo, 50% of the remaining non-OVX animals developed leiomyomas, but these were smaller and fewer than in OVX animals. On the basis of this model, we propose the hypothesis that some factors from the ovaries suppress leiomyoma growth in response to estrogen but that as the ovaries age this protection is diminished, allowing the clinical development of leiomyomas.

Carbohydrate metabolism studies after one year of using an oral contraceptive containing gestodene and ethinyl estradiol.

UNLABELLED: The objective of the study is to evaluate the effects of a gestodene-containing oral contraceptive on carbohydrate metabolism. The design of the study is prospective. The setting is at University of South Florida Outpatient Unit. The patients consisted of twenty-three normal women desiring contraception. Serum glucose and insulin levels were measured during a three-hour glucose tolerance test at control time and after one year of drug use. RESULTS: All of the one-year glucose values were significantly elevated as well as the fasting and three-hour insulin values. These changes were mostly confined to women over 26 years of age and not in the younger 18 to 23 year olds. An oral contraceptive containing 75 micrograms of gestodene and 30 micrograms of ethinylestradiol can significantly alter carbohydrate metabolism in older women.

PIP: In Tampa over a 1-year period, health workers followed 23 normal 18-34 year old women, who came to the University of South Florida Outpatient Unit for an oral contraceptive (OC) prescription, to examine the carbohydrate metabolic effects of an OC containing 75 mcg gestodene and 30 mcg ethinyl estradiol. No one conceived. All the glucose values increased significantly over the 12-month study period (p = .002). The significant increase was restricted to only women in the 26-34 year old group at fasting and 0.5, 1, and 2 hours (p .05), however. The fasting and 3 hour insulin values were significantly elevated (p .001 and .002, respectively). The elevated insulin values were largely confined to the 26-34 year old group (at 0.5, 1, and 3 hours), but they were also elevated at fasting and 3 hours in the 18-23 year old group. Even though the values of carbohydrate metabolic parameters were significantly elevated, the values were in the normal physiologic range. Since gestodene has little estrogen binding capacity and estrogen improves carbohydrate metabolism, this combined OC tends to have adverse effects on carbohydrate metabolism, particularly in older women. Longer and larger duration studies are needed to examine whether these effects increase or reverse with time.

Six-month carbohydrate metabolism studies in women using oral contraceptives containing gestodene and ethinyl estradiol.

Twenty-five women had their carbohydrate metabolism prospectively evaluated during the six months that they used a gestodene and ethinyl estradiol monophasic oral contraceptive. Serum glucose and insulin levels were measured during a 75-gram three-hour oral glucose tolerance test. At the six-month test, the three-hour glucose and the fasting and three-hour insulin values were significantly elevated. The literature on carbohydrate metabolism during gestodene oral contraceptive use is also reviewed.

PIP: The effects of combination-type oral contraceptives (OCs) (containing 75 mcg of the progestin gestodene and 30 mcg of ethinyl estradiol [EE] on carbohydrate metabolism during 6 months of use was evaluated in 25 women with a mean age of 26.1 +or- 1.1 years, parity of .7 +or- .1, and mean control weight of 143.5 +or- 6.1 pounds. An oral glucose tolerance test was performed after a 10-hour fast and a venous blood sample was taken. After drinking 75 g of glucose, repeat blood samples were drawn. After 6 cycles of OC use each subject was given another oral glucose tolerance test. The mean weight was 144.2 +or- 6.2 pounds. No complications and pregnancies occurred. The serum glucose 3-hour value was significantly elevated at the 6-month test. Also, significant increase of the fasting and 3-hour values of insulin were found. The results suggest that gestodene is capable of altering carbohydrate metabolism via its androgen receptor activity. Triphasic preparations (1650 mcg of gestodene and 680 mcg of EE) have a similar effect on carbohydrate metabolism as do monophasic pills (1575 mcg of gestodene and 630 mcg of EE) because of similar total steroid dose. OCs containing low-dose gestodene may alter carbohydrate metabolism to some extent but the longterm effects require further investigation as such new OCs have not been proved to be superior to existing formulations.

Carbohydrate metabolism after three months of using a gestodene-containing monophasic oral contraceptive.

Carbohydrate metabolism was prospectively evaluated in twenty-one normal women prior to and during their use for three months of a monophasic oral contraceptive containing the progestin gestodene plus ethinyl estradiol. The women had a three-hour oral glucose tolerance test using a 75 gram glucose load, measuring serum glucose and insulin levels. The results demonstrate no significant changes in either of the carbohydrate metabolic indices between the two tests. These data support the safety of this new progestin-containing contraceptive.

Carbohydrate metabolic studies in women using a levonorgestrel/ethinyl estradiol containing triphasic oral contraceptive for eighteen months.

Carbohydrate metabolism was evaluated in 17 women before and after 18 months of triphasic oral contraceptive use. The triphasic oral contraceptive contained levonorgestrel and ethinyl estradiol. An oral glucose tolerance test was utilized and both plasma glucose and insulin levels were measured. There were no significant changes in the glucose levels. The fasting insulin level was raised at the 18-month test, whereas the other insulin values were similar. These results demonstrate that the new triphasic oral contraceptive preparations produce minimal carbohydrate metabolic changes.

Two-year carbohydrate metabolism studies in women using a norethindrone or levonorgestrel triphasic oral contraceptive.

Carbohydrate metabolism was prospectively studied in 28 women using triphasic oral contraceptives (TOC) for two years. They were tested using a 100-gram oral glucose tolerance test with measurements of plasma glucose and insulin levels during the three-hour test. The women were randomly assigned to either a norethindrone-containing TOC or a levonorgestrel-containing TOC. Both types of drugs contained the estrogen ethinyl estradiol. No significant changes were noted in the norethindrone TOC group. The levonorgestrel TOC two-year test had a significant elevation of the 0.5- and 2-hour plasma glucose values and the fasting insulin value. These data show that the two triphasic oral contraceptive preparations affect carbohydrate metabolism differently.

Plasma glucose and insulin levels during the menstrual cycles of normal women and premenstrual syndrome patients.

Three-hour oral glucose tolerance tests were performed on days 5 and 25 of ovulatory menstrual cycles in 26 women. The women were divided into normal (n = 9) and premenstrual syndrome (PMS) (n = 17) categories. Ovulation was confirmed by basal body temperature records and plasma progesterone levels. There were no statistically significant changes in the plasma glucose or insulin levels between the two tests in either group. Except for a higher two-hour plasma insulin concentration on the day 5 test in normal women, no statistically significant carbohydrate differences were noted between the groups. The data suggest that alterations in carbohydrate metabolism are not important in PMS.

Glucose and insulin levels after six months of treatment with a triphasic oral contraceptive containing ethinyl estradiol and norethindrone.

A prospective study of carbohydrate metabolism was done on 33 women who used a triphasic oral contraceptive (OC) containing ethinyl estradiol and norethindrone for six months. A three-hour oral glucose tolerance test was administered before and after the OC usage, and both the blood glucose and insulin levels were determined. A significant decrease in the fasting glucose level was found with treatment. All other glucose values and insulin levels were unchanged.

PIP: To evaluate the effects of a triphasic oral contraceptive (OC) containing ethinyl estradiol and norethindrone on carbohydrate metabolism, both blood glucose and insulin levels were measured over the 6-month study period in 33 new acceptors. An identical oral glucose tolerance test was administered to each study subject immediately before commencing OC use and again during the 6th cycle of treatment; thus, each subject served as her own control. All glucose tolerance test results were normal and all fasting values were under 100 mg%. The only change accompanying triphasic OC use was a significant decrease in fasting glucose values. Mean control levels of plasma glucose (mg%) were 74.1 after a 10-hour fast and 113.4, 94.9, 89.7, and 86.2 0.5, 1, 2, and 3 hours, respectively, after consumption of 100 grams of glucose. 6-month levels averaged 70.2 at fasting, 115.3 at 0.5 hours, 102.3 at 1 hour, 92.8 at 2 hours, and 87.5 at 3 hours. The mean total insulin value was 213.7 + or - 27.4 mcgU pretreatment and 218.5 + or - 17.3 after 6 months of OC use--a nonsignificant difference. Earlier studies have demonstrated alterations in carbohydrate metabolism in users of high-dose OCs, presumably attributable to the progestogen component. Triphasic formulations achieve maximum reduction of the progestogen content of OCs by using 3 different doses throughout the month. Future longterm studies of users of low-dose and triphasic OCs are expected to show minimal clinical sequelae in the vascular systems of users.