Neonatal outcomes following a tight nuchal cord.

OBJECTIVE: The best practices for the care of a neonate born after a tight nuchal cord have not been defined. As a step toward this, we compared the outcomes of neonates born after a tight nuchal cord vs those born after a loose nuchal cord vs those born after no nuchal cord. STUDY DESIGN: This was a retrospective comparison using electronic data of all deliveries during a 6-year period (2005 to 2010) in a multihospital healthcare system in the western United States. At the time of delivery, each birth was recorded as having a tight nuchal cord, a loose nuchal cord or no nuchal cord. Nuchal cord was defined as a loop of umbilical cord ≥360° around the fetal neck. 'Tight' was defined as the inability to manually reduce the loop over the fetal head, and 'loose' as the ability to manually reduce the loop over the head. RESULT: Of 219,337 live births in this period, 6.6% had a tight nuchal cord and 21.6% had a loose nuchal cord. Owing to the very large number of subjects, several intergroup differences were statistically significant but all were judged as too small for clinical significance. For instance, those with a tight nuchal cord had a very slightly older gestational age, a very slightly lower birth weight, a preponderance of male fetuses, primagravid women, singleton pregnancies and shoulder dystocia (all P<0.001). Term neonates with a tight nuchal cord were slightly more likely to be admitted to a Neonatal Intensive Care Unit (6.6% vs 5.9% admission rate, P=0.000). Those with a tight nuchal cord were not more likely to have dopamine administered or blood hemoglobin measured on the first day, nor were they more likely to receive a transfusion or to die. The subset of very low birth weight neonates with a tight nuchal cord, compared with those with no nuchal cord, were of the same gestational age and birth weight, with the same Apgar scores, and were not more likely to have severe intraventrucular hemorrhage, retinopathy of prematurity or periventricular leukomalacia, or to die. CONCLUSION: The presence of a tight nuchal cord is not uncommon, occurring in 6.6% of over 200,000 consecutive live births in a multihospital health system. No differences in demographics or outcomes, judged as clinically significant, were associated with a tight nuchal cord. Thus, we speculate that the best practices for neonatal care after a tight nuchal cord do not involve an obligation to conduct extra laboratory studies or extra monitoring solely on the basis of the report of a tight nuchal cord.

Venous thromboembolism and pregnancy.

Venous thromboembolism remains a major cause of maternal morbidity and mortality. Pregnancy is a thrombogenic state; therefore, clinicians must be familiar with the diagnosis and treatment of acute VTE. It is of paramount importance when caring for pregnant women to understand which patients are at risk for VTE and to use thromboprophylactic heparin accordingly.

Recent cocaine use is not associated with fetal acidemia or other manifestations of intrapartum fetal distress.

The objective of this paper is to evaluate the impact of recent cocaine use on umbilical cord blood gas values in cocaine-dependent pregnant women who received formal prenatal care. Ninety-two cocaine-dependent pregnant women receiving comprehensive prenatal care were divided into two groups, with patients in Group A (n = 35) testing positive for cocaine metabolites at the time of delivery and Group B (n = 57) testing negative. One hundred and three patients with no history of drug or alcohol dependence served as the control group (Group C). Umbilical cord blood gases were obtained at all deliveries. Additional variables included 1 and 5-min Apgar scores, meconium staining of the amniotic fluid, route of delivery, premature rupture of the membranes, and length of nursery stay. There were no statistically significant differences between groups in either umbilical artery pH, pO2, pCO2, bicarbonate, or base excess. Similarly, there was no difference in meconium staining of the amniotic fluid, depressed Apgar scores, cesarean delivery, or neonatal length of stay. Our data do not support an association between recent cocaine use and fetal hypoxemia or acidemia, depressed 5-min Apgar scores, meconium staining of the amniotic fluid, or cesarean delivery in cocaine-dependent pregnant women enrolled in prenatal care.

Perinatal complications associated with maternal tobacco use.

The use of tobacco products by pregnant women is associated with placenta previa, abruptio placentae, premature rupture of the membranes, preterm birth, intrauterine growth restriction and sudden infant death syndrome. Approximately 15-20% of women smoke during pregnancy. It has been suggested that smoking is responsible for 15% of all preterm births, 20-30% of all infants of low birthweight, and a 150% increase in overall perinatal mortality. Cigarette smoking is one of the most important and modifiable risk factors associated with adverse perinatal outcomes.

Clinical utility of routine postpartum hemoglobin determinations.

The objective of this paper was to determine if routine postpartum hemoglobin (Hb) determination changes patient management. One thousand patients with a vaginal delivery at Hermann Hospital, Houston, TX, had antepartum Hb testing, and a postpartum Hb for: (1) an antepartum Hb <9.0 mg/dL, (2) an estimated blood loss (EBL) >500 mL, (3) abnormal orthostatic vital signs, and (4) physician discretion. Data collected included: antepartum and postpartum Hb, EBL at delivery, the indication for Hb determination, and orthostatic vital sign results. Three-hundred fifty-eight postpartum hemoglobins were performed, most were "routine." Patients whose EBL was >500 mL were twice as likely to be anemic after delivery (RR 2.39, 95% CI 1.40, 4.08). Orthostatic hypotension had a PPV of only 21% for postpartum anemia. With the exception of an EBL >500 mL, risk factors for postpartum anemia are poorly predictive. Orthostatic vital signs are an insensitive test for the detection of anemia. Minimizing routine Hb testing following vaginal deliveries appears safe without an impact on patient management.

Association between umbilical blood gas parameters and neonatal morbidity and death in neonates with pathologic fetal acidemia.

OBJECTIVE: Our purpose was to correlate umbilical artery blood gas parameters with neonatal death and indicators of morbidity in neonates with pathologic fetal acidemia (pH <7.0). STUDY DESIGN: We reviewed maternal and neonatal charts of 93 neonates with an umbilical artery pH <7.0 who were delivered at 2 university-based centers. The relationships between umbilical artery pH, PO (2), PCO (2), bicarbonate, base deficit, and neonatal variables-death, need for intubation, cardiopulmonary resuscitation, seizures, hypoxic-ischemic encephalopathy, respiratory distress syndrome, intraventricular hemorrhage, meconium, sepsis, and intrauterine growth restriction-were determined with the Student t test, Mann-Whitney U test, and multiple logistic regression analysis. Data are presented as either median with 25th-75th percentiles or mean +/- SD. RESULTS: The mean gestational age at delivery was 37.9 +/- 3. 6 weeks, and the mean birth weight was 3003 +/- 866 g. There was no relationship between neonatal death, respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, patent ductus arteriosus, meconium, sepsis, and any umbilical artery blood gas parameter. The PO (2) was not related to any of the variables studied. A lower umbilical artery pH was associated with hypoxic-ischemic encephalopathy (6.69 vs 6.93, P =.03), cardiopulmonary resuscitation (6.83 vs 6.93, P =.03), seizure (6.75 vs 6.93, P =.02), intubation (6.83 vs 6.94, P <.001), and intrauterine growth restriction (6.72 vs 6.93, P =.01). Greater mean base deficit was associated with seizure (20.6 vs 15, P =.01), intubation (18.0 vs 13.7, P <.001), cardiopulmonary resuscitation (18.5 vs 15.0, P =.03), intrauterine growth restriction (22.0 vs 14. 0, P =.02), and hypoxic-ischemic encephalopathy (24.0 vs 14.5, P =. 03). Arterial PCO (2) was higher only in infants with hypoxic-ischemic encephalopathy (138 vs 95.5, P =.048), intubation (106.0 vs 90.5, P =.003), and cardiopulmonary resuscitation (106.5 vs 93.0, P =.04). After control for birth weight and gestational age in the multivariate analysis, base deficit and bicarbonate were independently related to death or morbidity. CONCLUSION: Our data suggest that "pathologic" fetal acidemia is indicated by an umbilical artery pH <7.00 with a metabolic component. The metabolic component of fetal acidemia (ie, base deficit and bicarbonate) is the most important variable in subsequent neonatal morbidity. As expected, the umbilical artery PO (2) has no apparent clinical utility. The ability to predict more accurately which newborn infants with fetal acidemia are at risk of having complications may lead to a more efficient implementation of preventive measures.

Modern analysis of pathologic uterine rings.

A computerized medical record search of 61,406 live births from January 1, 1990, through December 31, 1994, identified 14 cases of pathologic uterine rings. This yielded an incidence of pathologic uterine rings of 0.02% of all live births. In a retrospective, matched study design, three control subjects having vaginal delivery and three having cesarean delivery were matched with each case of pathologic uterine ring for age, race, parity, estimated gestational age, single or multiple gestation, primary or repeat cesarean section, and indication for the cesarean delivery. Comparison with controls who had cesarean section showed no significant differences in duration of labor, rupture of membranes, use of oxytocin, or fetal head position. Pathologic uterine rings continue to occur in modern obstetrics, but their reported incidence has decreased. These data suggest that the characteristics of parturition have no clear association with the formation of a pathologic uterine ring.

Correlation of urine and serum benzoylecgonine levels in pregnant women.

The objective of this study was to evaluate the correlation between urine and serum benzoylecgonine (BE) levels in pregnant women who use crack cocaine. Ten women who had recently smoked crack cocaine were recruited from a prenatal substance abuse clinic to participate in this study. Urine and serum were obtained concurrently for quantitative determination of BE, (the major metabolite of cocaine), using gas chromatography/mass spectrometry. Pearson correlation was used for statistical analysis. The median reported interval since most recent crack use was 35 hours (range 9.5 to 63 hr). The median gestational age of the subjects was 31 weeks (range 22 to 38 weeks). Urine benzoylecgonine levels ranged from 1038 ng/mL to 1,950,563 ng/mL and serum BE levels ranged from 2.5 to 3074.3 ng/mL. Pearson correlation for urine and serum BE levels was 0.92, p < 0.001. This is the first study to report the correlation between urine and serum BE levels in pregnant women who use crack cocaine.

Social, ethical and practical aspects of perinatal substance use.

Substance use in pregnancy has garnered increasing attention over the last decade as a particularly concerning facet of the larger national drug problem. This concern stems from the unique circumstance presented by pregnancy, in which the fetus may suffer harm as a result of maternal behavior. Furthermore, organizing a response to this problem is complicated by the ethically and legally challenging nature of the maternal-fetal relationship. The medical implications of perinatal substance use are profound. A discussion of these associated medical and obstetrical complications lies outside the focus of this paper, and the reader is referred to other reviews (Andres & Jones, 1994; Robins & Mills, 1993). This article is intended to assist obstetricians and others in their approach to the substance using pregnant patient. We first review the scope of this problem in social and financial terms and then review the important ethical and legal issues involved in current policymaking. Lastly, we suggest a clinical intervention focusing on education and improvement in identification and management of this subset of patients.

Teratogenic potential of cocaine.

Cocaine has been implicated as a potential cause of congenital abnormalities since the mid 1980s. Clinical studies have reported an increased risk of cardiovascular and central nervous system abnormalities as well as an increased incidence of limb reduction defects and intestinal atresias. The published data have not established an unequivocal link between cocaine and these abnormalities. The most compelling evidence for the role of cocaine as a teratogen is the increased risk of genitourinary tract defects. Although animal models have also yielded contradictory conclusions, it is intriguing to note that the abnormalities observed in these models are similar to those seen clinically. This review summarizes the clinical and basic research relating to the teratogenic potential of cocaine.

The association of cigarette smoking with placenta previa and abruptio placentae.

Smoking was recognized as having an adverse effect of pregnancy outcome as early as the mid 1950s. Smoking is a well recognized risk factor for low birthweight infants and has been implicated in preterm birth. The increased risk of both placenta previa and abruptio placentae among women who continue to smoke during pregnancy, is in general, less well recognized, but supported by numerous studies. The purpose of this article is to review the published literature dealing with the risk of placenta previa and abruptio placentae in women who smoke during their pregnancy.

Cocaine alters placental production of thromboxane and prostacyclin.

OBJECTIVE: The objective of this study was to test the hypothesis that cocaine alters placental prostaglandin production in vitro. STUDY DESIGN: Placentas were obtained from healthy women (n = 6) after normal vaginal delivery at term. Placental explants (300 mg) were incubated in duplicate at 37 degrees C in the presence of 0, 30, 300, or 3000 ng/ml cocaine. Thromboxane and prostacyclin production was measured by radioimmunoassay of their stable metabolites (thromboxane B2 and 6-keto-prostaglandin F1 alpha) at 0, 0.5, 1.0, 1.5, 2, 4, 8, and 12 hours. Analysis of variance with Newman-Keuls test was used for statistical analysis. RESULTS: Cocaine increased thromboxane production in a dose-dependent manner (p < 0.001) and decreased prostacyclin production (p < 0.05). Cocaine increased the ratio of thromboxane/prostacyclin production (p < 0.05). CONCLUSION: Cocaine alters the placental production of prostaglandins in vitro, favoring thromboxane production, which may cause vasoconstriction and decrease uteroplacental blood flow.

The ovine fetal sympathoadrenal response to the maternal administration of methamphetamine.

OBJECTIVE: We hypothesized that maternally administered methamphetamine would alter fetal sympathoadrenal activity. STUDY DESIGN: Six chronically catheterized near-term pregnant ewes received an intravenous bolus injection of methamphetamine (1.25 mg/kg). Maternal and fetal arterial blood gas values, glucose, insulin, lactate, and catecholamines were measured in the control period and at 15, 30, 60, 90, 120, and 180 minutes after methamphetamine. RESULTS: Fetal PO2 decreased from 21.4 +/- 1.9 mm Hg at control measurement to 15.3 +/- 3.3 mm Hg after 60 minutes (p < 0.05). Fetal pH declined from 7.35 +/- 0.014 at control to 7.29 +/- 0.024 after 180 minutes. Fetal plasma glucose rose from 15.3 +/- 2.4 mg/dl at control to peak at 51.2 +/- 6.8 mg/dl at 120 minutes. Insulin levels increased from a control of 40.5 +/- 8.06 to a peak of 128 +/- 46 microIU/ml at 180 minutes (p < 0.05). Lactate levels increased from a baseline of 33.5 +/- 2.0 mg/dl to 92.3 +/- 22.8 mg/dl at 180 minutes. Fetal catecholamines rose from a baseline of 153 +/- 20.2 pg/ml for epinephrine and 226 +/- 18.5 pg/ml for norepinephrine to maximum values of 518 +/- 87.3 and 661 +/- 59.3 pg/ml at 15 minutes (p < 0.05), declining thereafter. CONCLUSIONS: Maternal administration of methamphetamine is associated with a short-term increase in circulating fetal catecholamines followed by hyperglycemia, lactacidemia, and hyperinsulinemia. These findings suggest that the alteration of fetal sympathoadrenal activity may contribute to the various perinatal complications associated with methamphetamine use.

Recurrent Bandl's ring as an etiology for failed vaginal birth after cesarean section.

A pathologic retraction ring (Bandl's ring) of the uterus is a constriction located at the junction of the thinned lower uterine segment and the thick retracted upper uterine segment that is associated with obstructed labor. The following is the first reported case of recurrent pathologic retraction ring and an attempted vaginal birth after cesarean section following such an abnormality.

Cocaine acutely increases rat myometrial contractile activity by mechanisms other than potentiation of adrenergic pathways.

OBJECTIVE: We hypothesized that cocaine acutely increases contractile activity in isolated rat myometrium and that this effect is solely caused by potentiation of adrenergic pathways. STUDY DESIGN: Isometric contractions were measured in myometrium isolated from virgin and day-18 pregnant Sprague-Dawley rats. Frequency, duration, amplitude, and integrated area were compared before and after the addition of cocaine (10(-6) to 10(-4) mol/L) by means of analysis of variance and Duncan's multiple-range test. The effects of alpha-adrenergic receptor antagonists (prazosin 10(-6) mol/L and yohimbine 10(-6) mol/L) and beta-adrenergic receptor antagonist (DL-propranolol 2 x 10(-6) mol/L) were assessed. RESULTS: Contraction duration, expressed relative to control, increased acutely after cocaine (10(-5) mol/L) administration in pregnant (1.70 +/- 0.20) and nonpregnant (1.36 +/- 0.24) myometrium (mean +/- SE, p < 0.05), as did integrated area (pregnant 3.47 +/- 0.97, nonpregnant 2.48 +/- 0.66) (mean +/- SE, p < 0.05). These effects were not completely inhibited by adrenergic blockade. CONCLUSION: Cocaine acutely increases the duration and integrated area of spontaneous contractions in isolated rat myometrium by mechanisms not completely explained by inhibition of catecholamine reuptake and potentiation of adrenergic pathways.

The acute effect of cocaine exposure on pregnant human myometrial contractile activity.

OBJECTIVE: The objective of this study was to test the hypothesis that cocaine acutely increases contractile activity in isolated pregnant human myometrium. STUDY DESIGN: Myometrial samples were obtained from the lower uterine segment at elective cesarean section from five women at term who were not in labor and who had no perinatal risk factors. Myometrial strips were suspended in contractile buffer, and isometric contractions were measured. Frequency, amplitude, duration, and integrated area (mean +/- SE) were compared before and after the addition of cocaine (10(-6) to 10(-4) mol/L) by means of analysis of variance and Duncan's multiple range test. RESULTS: Contraction duration, expressed relative to control, increased acutely after addition of cocaine (10(-5) mol/L, 2.0 +/- 0.29; 10(-4) mol/L, 2.8 +/- 0.64) (p < 0.001). Integrated area of contractions also increased relative to control (10(-6) mol/L, 1.6 +/- 0.18, p < 0.05; 10(-5) mol/L, 2.4 +/- 0.16 and 10(-4) mol/L, 3.5 +/- 0.23, p < 0.001). These effects were dose dependent. CONCLUSION: Cocaine acutely increases contractile activity in myometrium isolated from pregnant women.

Left thoracic duct lymph flow responses to angiotensin II or atrial natriuretic factor infusion in the ovine fetus.

In the ovine fetus it is known that left thoracic duct lymph flow rate relative to body weight is four to five times adult levels, but it is not known whether the circulating hormones modulate fetal lymph flow. To explore this, we intravenously infused either angiotensin II (10 to 400 ng/min, n = 8) or atrial natriuretic factor (500 to 1000 ng/min, n = 8) into chronically catheterized fetal sheep for 30 minutes. Significant increases occurred in fetal arterial (p less than 0.0001) and venous (p = 0.018) pressures during the angiotensin II infusion, and thoracic duct lymph flow rate underwent a dose-dependent increase (r = 0.888, p = 0.0033). With termination of the angiotensin II infusion, fetal vascular pressures rapidly returned to control levels, and lymph flow fell from 18.8% +/- 10.1% (mean +/- SE) above control to 13.7% +/- 7.7% below preinfusion levels (p less than 0.01). During the atrial natriuretic factor infusion, fetal arterial pressure and circulating blood volume decreased significantly (p less than 0.01), whereas thoracic duct lymph flow was unchanged. After termination of the atrial natriuretic factor infusion, fetal arterial pressure returned toward control, blood volume remained reduced, and lymph flow rate underwent a transient rise to 35.6% +/- 15.7% (p less than 0.05) above control levels. These data suggest that angiotensin II and atrial natriuretic factor have significant but opposite effects on fetal thoracic duct lymph flow rate, with angiotensin II stimulating and atrial natriuretic factor suppressing lymph flow.

A reappraisal of the need for autologous blood donation in the obstetric patient.

There has been recent interest in autologous blood donation in obstetric patients, but little attention has been paid to whether such programs are needed or whether the patients that will require transfusion can be accurately predicted. At the University of California San Diego Medical Center from July 1 to Dec. 31, 1988, there were 2265 deliveries; 13 women (0.57%) received blood transfusions. Traditionally accepted risk factors were identified in 251 patients, with only four (1.6%) requiring transfusion. Among the 150 patients delivered by repeat cesarean section, only one (0.7%) required blood. one of 27 (3.7%) multiple gestations, two of eight (25%) patients with placenta previa, and none of the 66 grandmultiparous women had transfusions. These data suggest that autologous blood donation may not be beneficial or cost effective when the low frequency of blood transfusions in this high-risk obstetric population and the difficulty in accurately predicting those likely to require transfusions are considered.

The association of maternal floor infarction of the placenta with adverse perinatal outcome.

Maternal floor infarction of the placenta is a relatively rare disorder that on gross examination is characterized by a thickened gray-yellow maternal floor of the placenta with histologic evidence of massive fibrin deposition involving the decidua basalis and the contiguous villi. This lesion has been associated with fetal death, preterm delivery, and intrauterine growth retardation and is thought to be recurrent. Sixty cases of maternal floor infarction were identified in 48 women. Fetal death occurred in 24 of the 60 cases (40%). Preterm birth occurred in 21 of 36 (58.3%) live-born infants, and 19 of the 35 (54.2%) live-born infants for whom a birth weight was known had evidence of intrauterine growth retardation. Among the 41 multiparous patients in our series there were five documented recurrences (12.2%). Review of the past reproductive history of these 48 patients (196 pregnancies) demonstrated a significant incidence of fetal death (24.1%), intrauterine growth retardation (31.3%), and preterm death (35.4%). The association of fetal death and maternal floor infarction emphasizes the importance of a placental examination with all cases of fetal death and infants with intrauterine growth retardation. Given the risk of recurrence, the identification of maternal floor infarction should alert the clinician to the potential for growth retardation, preterm birth, and fetal death in subsequent pregnancies.