Lewis H. Nelson

The effect of placental location on uterine artery flow velocity waveforms

We examined the effect of placental location with regard to flow velocity waveforms in the uterine arteries in 84 control and 28 hypertensive women during the third trimester of pregnancy. The ratio of systolic peak to end-diastolic frequency was obtained with a continuous-wave Doppler device and the placental location was determined by real-time ultrasonography. In both normal and hypertensive pregnancies with unilateral placental location the systolic/diastolic ratio of the ipsilateral uterine artery was significantly lower than the contralateral artery ratio [1.73 +/- 0.35 (systolic/diastolic ratio) versus 2.46 +/- 0.73, p less than 0.001, and 2.38 +/- 1.01 versus 4.04 +/- 1.77, p = 0.0012, respectively]. The physiologic and clinical significance of this finding is discussed.

Maternal serum α-fetoprotein screening in North Carolina: Experience with more than twelve thousand pregnancies

A total of 12,084 patients participated in a maternal serum alpha-fetoprotein (AFP) screening program in central North Carolina between July 1, 1978, and June 30, 1982. Fifteen open neural tube defects were detected and three others were missed, resulting in a detection rate of 83%. With a cutoff of 2.5 times the normal median, 3.7% of patients screened had a single maternal serum AFP elevation, 2.1% had two successive elevations, and 1.2% became candidates for amniocentesis. Of those patients offered amniocentesis, one in 10 was found to have a fetus with a neural tube defect. No normal fetuses have been aborted. Patients with maternal serum AFP elevations were shown to have a substantially increased risk of fetal loss. Low maternal serum AFP levels were also a significant finding and led to recognition of less advanced gestational age, fetal death, or molar pregnancy in a number of cases.

Outcomes in patients with unusually high maternal serum α-fetoprotein levels

In a study group of 1,66 patients with unusually high maternal serum α-fetoprotein values ≥5 multiples of the median, 110 (66%) patients had a condition affecting obstetric care compared with 14% in the 2.5 to 2,9 range, 26% in the 3.0 to 3.9 range, and 30% in the 4 to 4.9 range of multiples of the median. Fetal anomalies composed a significantly greater proportion (p

Elevated maternal serum α-fetoprotein levels and oligohydramnios: Poor prognosis for pregnancy outcome

The outcome of 21 pregnancies with elevated maternal serum alpha-fetoprotein levels associated with oligohydramnios was studied. Seven of the 21 pregnancies ended in spontaneous abortion or intrauterine fetal death before week 24 of pregnancy. Five patients experienced premature labor between 24 and 26 weeks of gestation; each fetus was either stillborn or died in the immediate neonatal period. Four patients were delivered of infants after 32 weeks of gestation; each infant was either stillborn or died in the immediate neonatal period. Four patients electively had their pregnancies terminated. One patient was delivered at term of a healthy, growth retarded male infant who on follow-up at age 17 months was developmentally normal. Only three cases were associated with a fetal defect. Patients should be counseled that, even in the absence of a demonstrable cause for diminished amniotic fluid on ultrasonography, raised maternal serum alpha-fetoprotein levels coupled with oligohydramnios seem to carry a poor prognosis.

Addition of magnesium sulfate improves effectiveness of ritodrine in preventing premature delivery

From October, 1981, to July, 1983, 225 patients were evaluated for premature labor at Forsyth Memorial Hospital. Sixty-five of these patients were considered to be candidates for intravenous ritodrine treatment. Of this group, 24 patients were successfully treated and had pregnancy prolongation ranging from 1 to 17 weeks. Forty-one patients did not respond to maximal intravenous ritodrine therapy (300 to 350 micrograms/min). Eleven patients subsequently delivered within 24 to 48 hours of treatment initiation. The remaining 30 patients received intravenous magnesium sulfate (1 to 3 gm/hr) in addition to intravenous ritodrine. Eighteen patients responded favorably to this combination treatment and had pregnancy prolongation ranging from 1 to 11 weeks. Twelve patients delivered within 1 week from treatment initiation. In all cases where pregnancy prolongation was achieved, birth weight and neonatal outcome were significantly improved compared to patients who did not respond to either intravenous ritodrine alone or intravenous ritodrine and magnesium sulfate combination. Treatment related maternal/fetal complications were not significantly different in the various groups examined. From the foregoing we conclude that, in a select group of patients in premature labor not responding to conventional ritodrine therapy, magnesium supplementation in pharmacologic doses could have a beneficial effect with respect to pregnancy outcome.

C-reactive protein: a limited test for managing patients with preterm labor or preterm rupture of membranes?

C-reactive protein has been used to identify patients at high risk for infectious morbidity with preterm labor or preterm rupture of membranes. In this article we report on 104 patients with preterm labor symptoms (n = 45) or preterm rupture of the membranes (n = 59) and serial evaluations of C-reactive protein measured by latex agglutination and laser nephelometry. The simple, inexpensive latex method appears comparable to the laser method in predicting infectious morbidity and can be used clinically. Elevated C-reactive protein values before delivery predict infectious morbidity in only 8% to 29% of patients, and up to 18% of patients with serious infections may be misdiagnosed as having normal C-reactive protein values before delivery.

Megacystic-microcolon-hypoperistalsis syndrome and anechoic areas in the fetal abdomen

Abstract Diagnosis of congenital anomalies by ultrasound requires considerable skill and advanced equipment. A case of megacystis-microcolon-intestinal hypoperistalsis syndrome is presented and criteria are suggested for use in categorization of various ultrasound findings to isolate the defect to a major organ system. Identifying the involved system should aid in the differential diagnosis.

Prenatal Diagnosis and Pediatric Neurosurgery

Advances in realtime ultrasound imaging and a greater availability of high-quality ultrasound equipment have resulted in an increased number of congenital abnormalities being diagnosed prenatally in the last 10-15 years. In addition, testing for maternal serum alpha-fetoprotein, beta-human chorionic gonadotropin, and serum unconjugated estriol has allowed for more sensitive screening for congenital abnormalities. In response to this, in 1989 the Prenatal Diagnosis and Treatment Center was established at our institution to coordinate the care of fetuses and newborns with congenital malformations and to provide alternatives for the parents should the fetus not be carried to term. From January 1990 through June 1993, our group diagnosed 50 singleton pregnancies with various types of central nervous system disorders by the methods outlined above. Thirty-seven fetuses were diagnosed with neural tube defects. Of these, 5 were anencephalic and 1 had an encephalocele. The remaining 31 fetuses had meningomyeloceles with associated hydrocephalus. Of these 31, 18 fetuses were terminated prior to the age of viability as a result of our counseling and 13 fetuses were brought to term. Of the remaining 13 fetuses, 8 had hydrocephalus and 5 had various other diagnoses. Three of the eight hydrocephalic fetuses were either terminated, stillborn, or died following birth. Of the other 5 fetuses with hydrocephalus, 3 had shunts placed, 1 was followed with normal head growth, and 1 had normal ventricular size at birth. Using the methods available, the accuracy of diagnosis is very high, with only 1 fetus in this series being incorrectly diagnosed. Additionally the advantages of being able to counsel the parents regarding their unborn child allows them to make informed decisions. Accurate prenatal diagnosis plays a major role in the care of the fetus and in counseling parents prenatally for pediatric neurosurgical problems.

Gonococcal ventriculitis associated with ventriculoamniotic shunt placement

Use of a ventriculoamniotic shunt to control fetal hydrocephalus is a new procedure. Early experience suggests possible benefit to the fetus. Complications have been rare. This report describes the first case of Neisseria gonorrhoeae central nervous system infection associated with a ventriculoamniotic shunt and the third case reported in a neonate. On the basis of this clinical experience, we recommend that the mother be monitored closely for cervical pathogens, that delivery be performed prior to amniorrhexis, and that culturing of the shunt and ventricular fluid be carried out at delivery.

Gestational age alters fetal breathing response to intravenous insulin and intravenous glucose administration

Abstract An upward change in human maternal plasma glucose concentration is known to increase the percent of time spent in fetal breathing during the late third trimester of human pregnancy. We examined the fetal breathing effects of upward change in plasma glucose (after intravenous glucose administration) and downward change (after intravenous insulin administration) at two different times of day (8 am and 4 pm ) at both 24 and 36 weeks of gestation. No change in the percent of time spent in fetal breathing was seen after insulin infusion. Fetal breathing increased after glucose infusion at 36 weeks of gestation but not at 24 weeks. Responses did not differ between tests performed at 8 am and 4 pm .