Biomedical subjects

B M Mercer

Publications and source records attributed to B M Mercer.

85 records · Page 5Linked to original sources

PubMed1992

A randomized prospective comparison of nifedipine and bed rest versus bed rest alone in the management of preeclampsia remote from term.

OBJECTIVE: The objective of our study was to test the hypothesis that treatment with nifedipine for mild preeclampsia remote from term reduces the number of days of maternal hospitalization and improves pregnancy outcome. STUDY DESIGN: A total of 200 patients at 26 to 36 weeks' gestation were randomly allocated to treatment with either bed rest alone (n = 100) or bed rest in combination with nifedipine (n = 100). RESULTS: Patients receiving nifedipine had significantly lower systolic (p < 0.0001) and diastolic (p < 0.0001) blood pressures during therapy. Severe hypertension as an indication for delivery was significantly (p < 0.05) more frequent in the bed-rest-alone group. The two study groups had similar average days of maternal hospitalization (12.6 +/- 7.9 vs 12.3 +/- 10.3) and pregnancy prolongation (22.3 +/- 13.5 vs 22.5 +/- 15.7). There were no differences between groups with respect to birth weight, incidences of small-for-gestational-age infants and preterm birth, number of days spent in special care unit, or cord blood gas measurement. CONCLUSION: Nifedipine therapy for preeclampsia reduces maternal blood pressure but does not reduce number of days of maternal hospitalization or improve perinatal outcome.

Bed Rest↗

PubMed1992

Magnesium sulfate therapy in preeclampsia is associated with increased urinary cyclic guanosine monophosphate excretion.

OBJECTIVE: Our objective was to determine if maternal urinary cyclic guanosine monophosphate levels are altered in preeclampsia. STUDY DESIGN: Aliquots from 24-hour urine samples collected from 57 women with preeclampsia and 14 normotensive pregnant women in the third trimester of pregnancy were assayed for urinary cyclic guanosine monophosphate. Urinary cyclic guanosine monophosphate values were expressed per milligram of urinary creatinine to standardize for renal function. RESULTS: There was no difference in gestational age at time of urine collection between the two groups. Urinary cyclic guanosine monophosphate levels (mean +/- SD) were similar between normotensive and preeclamptic pregnant women (751 +/- 498 vs 632 +/- 363 pmol/mg urinary creatinine, respectively, p = 0.12). Preeclamptic women receiving magnesium sulfate had significantly higher levels of urinary cyclic guanosine monophosphate than those not receiving magnesium sulfate (786 +/- 360 vs 555 +/- 344 pmol/mg urinary creatinine, respectively, p = 0.02). CONCLUSIONS: These preliminary results indicated that cyclic guanosine monophosphate excretion increases in patients with preeclampsia during magnesium sulfate infusion. The vascular smooth muscle relaxation effects of magnesium sulfate may be mediated by directly increasing cyclic guanosine monophosphate production or indirectly through endothelium-derived relaxing factor.

Cyclic GMP↗

PubMed1992

Management of premature rupture of membranes before 26 weeks' gestation.

PROM occurring before 26 weeks' gestation is associated with significant maternal morbidity as well as neonatal morbidity and mortality. With aggressive expectant management, neonatal survival can be predicted for a 23% and 54% incidence of patients with PROM at or less than 22 weeks' and 23 to 26 weeks' gestation, respectively. Of those neonates who survive, 55% to 69% will be neurologically intact on long-term follow-up. Conservative management leading to prolonged latency provides the neonate with the greatest potential for survival as outcome generally reflects the gestational age at birth. However, lethal pulmonary hypoplasia may occur with prolonged leakage and oligohydramnios. The patient who wishes to pursue a course of expectant management should be monitored closely for signs of infection and labor. Expectant management should be undertaken in a facility with resources capable of caring for the mother at risk of significant morbidity and the very low birth weight neonate. Ongoing counseling and psychologic support are essential in the management of this morbid pregnancy complication.

Counseling↗

PubMed1991

Maternal plasma level of endothelin is increased in preeclampsia.

Endothelin is a potent vasoconstrictor that is reportedly increased in conditions characterized by endothelial damage. Maternal plasma endothelin levels were compared between 27 women with preeclampsia (23 without and 4 with the hemolysis, elevated liver enzymes, and low platelet count syndrome) and 14 women with normotensive pregnancies. The mean +/- SEM plasma endothelin values were significantly higher in patients with preeclampsia uncomplicated by the hemolysis, elevated liver enzymes, and low platelet count syndrome (5.48 +/- 0.30 fmol/ml vs 3.86 +/- 0.28, p less than 0.001). In addition, the preeclamptic group with the hemolysis, elevated liver enzymes, and low platelet count syndrome had significantly higher endothelin levels than those without the syndrome (8.30 +/- 1.62 fmol/ml vs 5.48 +/- 0.30, p less than 0.05). There was no correlation between plasma endothelin values and either systolic or diastolic blood pressure. We conclude that plasma endothelin levels are significantly increased in women with preeclampsia and particularly in those with the hemolysis, elevated liver enzymes, and low platelet count syndrome, suggesting an association with widespread endothelial damage.

Adult↗

PubMed1991

Enhanced endothelium-derived relaxing factor activity in pregnant, spontaneously hypertensive rats.

Pregnancy is normally associated with vasodilation that, in hypertensive animals such as the spontaneously hypertensive rat, causes a profound decrease in blood pressure. To test the possibility that enhanced basal endothelium-derived relaxing factor activity has a role in the vasodilation of pregnancy, we measured the changes in mean arterial pressure and heart rate induced by NG-monomethyl-L-arginine, a specific inhibitor of endothelium-derived relaxing factor synthesis, in conscious nonpregnant and pregnant (postmating day 20 to 21) normotensive Wistar-Kyoto and spontaneously hypertensive rats. NG-monomethyl-L-arginine caused similar dose-dependent increases in mean arterial pressure in nonpregnant and pregnant Wistar-Kyoto rats, but the accompanying decrease in heart rate was significantly greater in nonpregnant rats than in pregnant ones. In the spontaneously hypertensive rats, NG-monomethyl-L-arginine caused significantly greater dose-dependent increases in mean arterial pressure in pregnant compared with nonpregnant rats; there were no differences in the decreases in heart rate. These pressor responses were partially reversed by excess L-arginine but not D-arginine. Indomethacin had no effect on the pressor response to NG-monomethyl-L-arginine or the depressor response to L-arginine after NG-monomethyl-L-arginine. Therefore basal endothelium-derived relaxing factor plays a role in vascular tone and blood pressure regulation in vivo, and pregnancy may be associated with enhanced basal endothelium-derived relaxing factor activity in the hypertensive spontaneously hypertensive rats.

Animals↗

PubMed1991

Does unexplained second-trimester (15 to 20 weeks' gestation) maternal serum alpha-fetoprotein elevation presage adverse perinatal outcome? Pitfalls and preliminary studies with late second- and third-trimester maternal serum alpha-fetoprotein.

Several reports have suggested that persons with an unexplained maternal serum alpha-fetoprotein elevation at 15 to 20 weeks' gestation are at an increased risk for a variety of other pregnancy complications (e.g., preeclampsia) and adverse perinatal outcomes (e.g., fetal death, low-birth-weight infants). However, ascertainment biases could explain some of these reported findings, and predictive value of unexplained elevated maternal serum alpha-fetoprotein levels in the prediction of pregnancy complications seems limited. If elevated second-trimester levels were truly predictive of pregnancy complications, we reason that third-trimester levels could prove even more useful. We thus studied late second-trimester and early third-trimester (24 to 36 weeks' gestation) maternal serum alpha-fetoprotein levels with the same enzyme immunoassay we use to evaluate routine second-trimester (15 to 20 weeks' gestation) levels. Values rose up to 32 weeks and fell slightly thereafter. Variance was greater than at 15 to 20 weeks but not so great as to preclude clinical usefulness in the third trimester. Of 279 women with a normal (0.4 to 2.49 multiples of the median) maternal serum alpha-fetoprotein value at 15 to 20 weeks' gestation, 270 (96.8%) showed levels in the same range later in gestation; however, none of six singleton pregnancies with unexplained maternal serum alpha-fetoprotein levels greater than 2.50 multiples of the median at 15 to 20 weeks' gestation showed maternal serum alpha-fetoprotein levels in this range at 24 to 36 weeks' gestation. The relationship between second- and third-trimester maternal serum alpha-fetoprotein levels in abnormal pregnancies remains to be elucidated in a large sample. Thus we are conducting not only cohort but also cross-sectional studies. Preliminary findings suggest that women with preterm premature rupture of membranes or with premature labor show elevated late second-trimester and early third-trimester maternal serum alpha-fetoprotein levels; however, larger sample sizes are necessary.

Female↗

PubMed1991

Evaluation of two rapid group B streptococcal antigen tests in labor and delivery patients.

Two rapid group B streptococcal antigen tests were compared with nonselective blood agar culture in 1062 unselected patients admitted to labor and delivery. Vaginal specimens taken from each patient on admission were used to perform each of two rapid tests and corresponding cultures. The rapid tests were the Streptex latex agglutination assay and the Equate Strep B test, which uses a solid-phase immunoassay. Overall, 105 patients (9.9%) had at least one positive culture. The sensitivities for the rapid tests were 15.1% for Streptex and 21.5% for Equate. Specificities were 99.3 and 98.7%, respectively. Sensitivity was minimally increased in the setting of ruptured membranes for both tests. Likewise, use of separate swabs for streaking the culture plate and performing the rapid test increased the sensitivity, but this was not significant for either test. In control experiments, the limit of sensitivity of both rapid tests was 5 x 10(6) colony-forming units. We conclude that at present, these tests are not sensitive enough for routine use in this type of clinical setting.

Antigens, Bacterial↗

PubMed1990

Antepartum management of twin gestation: ultrasound.

1. The use of ultrasound may improve perinatal outcome in twin pregnancy. 2. Singleton growth curves for FL, BPD, and AC may be used to assess fetal growth prior to 28 weeks gestation. 3. After 28 weeks gestation, specific twin growth curves should be used. However, increased morbidity may be seen when fetal weight falls from the normal singleton predictive curves. 4. Amnionicity and chorionicity frequently can be determined. This should be attempted early in the second trimester so that appropriate monitoring can be offered for the monoamnionic and monochorionic gestations. 5. Serial assessment of fetal growth should be performed. In the authors' institutions, growth scans are performed in twins every 2 weeks after 24 weeks gestation. 6. Evidence on ultrasound examination of discordant growth suggests either fetal growth retardation or TTS. In the presence of a dichorionic placentation, growth retardation of one twin is the usual diagnosis. If placentation is monochorionic, it is difficult to differentiate between growth retardation and TTS. The presence of polyhydramnios, a stuck twin, or fetal hydrops are suggestive of TTS. 7. The value and safety of cordocentesis and the management of twin pregnancy and diagnosis of TTS have not been established. 8. Doppler ultrasound may be useful in the assessment of the IUGR twin fetus. The use of Doppler in the identification of TTS is not yet clear.

Amniocentesis↗

PubMed1987

Fetal foot length as a predictor of gestational age.

Ultrasonographic measurement of fetal foot length is useful in the assessment of gestational age. Two hundred twenty-three postpartum and 224 ultrasonographic measurements were performed between 11 and 43 weeks' gestation; 207 postpartum and 160 ultrasonographic measurements met our requirements of secure dates and no physical anomaly or maternal disease. Mean foot length at each week of gestation compared favorably with Streeter's data, based on pathologic specimens, described in 1920. Comparison of curvilinear regression of foot length versus gestational age demonstrated a strong correlation with an R2 value of 0.981; 95% confidence intervals at each week compared favorably with both biparietal diameter and femur length data. Fetal foot length is a reliable parameter for use in the assessment of gestational age and is particularly useful when other parameters do not accurately predict gestational age, for example, hydrocephalus, anencephaly, short limb dysplasia.

Female↗

PubMedDate not supplied

Improved intravaginal controlled-release prostaglandin E2 insert for cervical ripening at term. The Prostaglandin E2 insert Study Group.

The purpose of this study was to determine if prostaglandin E2 (PGE2) in a controlled-release vaginal insert with retrieval system can produce cervical ripening at term. This was a multicenter, double blind, randomized, placebo-controlled study involving 206 patients with 102 receiving active agent. A successful outcome was defined as a change in Bishop score of > or = 3, or a Bishop score of > or = 6 at 12 h or delivery within 12 h of the insert placement. Analysis was by Fisher's exact test, Wilcoxon's two-sample rank-sum test, and Student's t-test where appropriate. One hundred ninety-three women completed the protocol. Initial Bishop scores were 2.6 +/- 1.2 and 2.5 +/- 1.4 in the PGE2 and placebo groups, respectively. The incidence of cesarean delivery was identical in the two groups. Uterine hyperstimulation lasted 2-13 min in 5 PGE2 patients (4.9%) with 1 patient requiring tocolysis. More patients in the PGE2 group had a change in Bishop score of > or = 3 (62% vs. 40%; P = 0.002), a Bishop score > or = 6 after 12 h (46% vs. 34%; P = 0.11), and vaginal delivery within 12 h (6.5% vs. 1%; P = 0.055). Sixty-five percent of PGE2 group patients had a successful outcome vs. 44% of control patients (P = 0.001). In conclusion, when administered in a controlled-release vaginal insert with a retrieval system, PGE2 is effective in promoting cervical ripening at term.

Adult↗

PubMedDate not supplied

Septic pelvic thrombophlebitis or refractory postpartum fever of undetermined etiology.

The objective of this study was to review and characterize the presentation, diagnostic dilemmas, management, and prognosis of postpartum septic pelvic thrombophlebitis. Medical records of postpartum women with the diagnosis of septic pelvic thrombophlebitis were reviewed for the 8-year period 1986-1994. Cases of documented ovarian vein thrombosis or those with other pelvic pathology on imaging study were excluded. Thirty-one women, four following vaginal delivery and 27 following cesarean delivery, with a final diagnosis of septic pelvic thrombophlebitis were identified. All patients demonstrated refractory febrile morbidity (mean 5.5 +/- 1.9 days prior to instituting heparin therapy) despite multiagent antimicrobial therapy with ampicillin, gentamicin, and clindamycin. Imaging studies (CT and/or ultrasound) were performed in 20 women and revealed no pelvic pathology. The patients required an average of 4.7 +/- 2.1 days (median 5, range 1-9 days) of heparin therapy before defervescence. Heparin levels were therapeutic at a mean of less than 24 h (range 6-24 h). The average dose of heparin required was 16.0 +/- 3.0 U/kg/h. Nine women had 13 subsequent pregnancies without recurrent thromboembolic complications. Currently available imaging studies cannot diagnose the entity we now define as septic pelvic thrombophlebitis (once cases of ovarian vein thrombosis are excluded). Our findings do not support the time-honored rule that septic pelvic thrombophlebitis responds within 24-48 h to therapeutic anticoagulation with heparin. Therefore, criteria other than imaging studies or immediate defervescence following heparin therapy are necessary for diagnosis of septic pelvic thrombophlebitis. A more appropriate terminology for septic pelvic thrombophlebitis should be refractory postpartum fever of undetermined etiology.

Adolescent↗

PubMedDate not supplied

Use of maternal plasma level of zinc-coproporphyrin in the prediction of intrauterine passage of meconium: a pilot study.

OBJECTIVE: To evaluate the usefulness of maternal plasma zinc-coproporphyrin (ZCP) level as a marker for intrauterine passage of meconium. METHODS: A pilot study consisting of 10 pregnancies with meconium-stained amniotic fluid and 10 pregnancies with clear amniotic fluid was used. The corresponding plasma and amniotic fluid levels of ZCP were measured using spectrofluorometry. ZCP levels in plasma and amniotic fluid were compared between the two groups and the relation between plasma and amniotic fluid ZCP levels in the clear and meconium-stained groups was assessed using Spearman rank-order correlation. RESULTS: Mean amniotic fluid ZCP was significantly higher in the meconium-stained amniotic fluid as compared to the clear amniotic fluid group. Although mean plasma ZCP levels were higher in the meconium-stained amniotic fluid group, this difference was not statistically significant. There was no significant correlation between plasma ZCP levels and amniotic fluid ZCP, but we could categorize patients according to plasma ZCP levels into four categories with different risks for having meconium-stained amniotic fluid. CONCLUSIONS: Plasma ZCP might be a promising test for prediction of intrauterine passage of meconium in high-risk patients if confirmed by larger studies. The implications of this prediction on management remain unknown.

Adult↗

PubMedDate not supplied

Patient preference for self-collected cultures for group B streptococcus in pregnancy.

To determine pregnant women's preference for self-culture technique, 251 women between 24 and 42 weeks' gestation were interviewed after performing self-collected cultures (vaginal and rectal) for group B streptococcus. Patient receptiveness to self-culture, the ability to perform self-culture, and the desire for choice in the future were derived using the Patient Preference Tool. The majority of women (77%, n = 194) gave positive descriptions of self-culture technique, and the majority of women preferred self-culture technique over nurse-collected sampling (57%, n = 142). Seventy-nine percent (n = 197) stated their desire to have a choice about self-culture in the future when similar testing was needed, and 89% (n = 224) believed that other women would also like this choice. Additionally, patient samples were highly correlated with nurse-collected samples for accuracy of culture results. This study provides data supporting that women desire active participation in their care.

Adult↗