Predicting the duration of the first stage of spontaneous labor using a neural network.

To create a neural network that predicts the length of the first stage of term labor. Two hundred patients with gestations > or = 36 weeks, in spontaneous active labor are the study group: 159 for training and 41 for testing; 4 training set patients had second-stage cesarean section for obstructed labor. The network is designed with Brainmaker MacIntosh 1.0 (California Scientific Software). Inputs are uterine activity, estimated fetal weight, position, station, and gestational age; maternal parity, age, height, weight, membrane status, and cervical dilatation. Actual first stages are regressed on those predicted by the network or by a standard partogram set. Differences between actual first stage lengths and those predicted by the neural network or partogram are compared with t-tests; while the proportions of first stages accurately predicted within 1 or 2 h are compared for both methods with chi-square tests. The network trained in 4 h (1388 runs) to a 0.15 tolerance. The network predictions have significantly higher correlation (r = 0.88) than do standard partograms (r = 0.35) with actual first stage durations. Mean differences between predicted and actual first stages are significantly lower for network output than with partograms; these differences increased with first stages exceeding 3 h; 100% of trained network values are within 2 h of actual first stage length. The network performs similarly for a new set of 41 previously unseen labors. This neural network predicts the length of the first stage of spontaneous labor and uses inputs readily available to obstetricians. It outperforms typical partograms for estimating this important feature of normal labor. Future application for intrapartum prognosis could be based on this successful design.

The antepartum patient. Sudden changes in central nervous system status and sensorium.

An approach to the pregnant patient with altered consciousness is presented. The unconscious pregnant patient often represents a straightforward simple problem if the event is a minor syncope secondary to physiologic changes of pregnancy. Most loss of consciousness is postictal in nature after either an epileptic or eclamptic seizure. If these are ruled out, other more serious causes must be considered, and the patient must be fully evaluated by appropriate neurologic consultants.

Screening general obstetric populations for risk assessment. Who will need testing?

In spite of increasing emphasis on high-technology aids for antepartum screening, diagnosis, and care, the first steps to secure better outcomes for most pregnancies begin with basic preconception and early prenatal risk assessment. Although many well-studied tools are available for prospective care of the high-risk fetus, the impact of many maternal risk factors occurs prior to the time such approaches can be invoked. It is becoming more evident that preventive care may reduce or eliminate the toll exacted by some of the more frequent problems, such as poor nutrition, substance abuse, or failure to comply with effective regimens for treating common medical disorders. Schemes for reducing perinatal mortality place a premium on engaging the patient in her own risk management and early identification of problems. The role of patient education cannot be overemphasized. Making the pregnant woman an active member of her caretaking team is a good investment in time and effort.

Prenatal prediction of small- and large-for-gestational age neonates.

OBJECTIVE: To test the predictive accuracy of five fundal height growth curves in the identification of twin gestations and small-, appropriate-, and large-for-gestational age neonates. DESIGN: Retrospective review of prenatal records. SETTING: Perinatal clinic at a tertiary-care center. PARTICIPANTS: Five hundred seven medically indigent women. MEASURES: Fundal height measurements were tested against the limits of normal for each week of gestation on five fundal height curves. Neonates were classified as small-, appropriate-, or large-for-gestational age (based on weight for gestational age), except for twin gestations, which were classified as twins. RESULTS: The accuracy of the predictions depended on which curve was used and what criteria were used to classify fundal height measurements as abnormal. Small-for-gestational age neonates (n = 40) were correctly predicted in 27.5-70% of the cases, large-for-gestational age neonates (n = 74) in 36.5-98.6% of the cases, and all four twin gestations. CONCLUSIONS: Clinicians should test the accuracy of any fundal height curve before using it in practice.

Care in early pregnancy.

This century has seen marked improvement in perinatal outcomes but prematurity remains a problem the world over. To improve these results requires more attention to early pregnancy or even pre-pregnancy care. Control of pre-existing conditions, improved social behavior in nutrition, smoking cessation and other factors are discussed.

The effect of maternal bladder volume on fundal height measurements.

The effect of maternal bladder volume on fundal height measurements was studied in 200 non-obese Black women between 16 and 42 weeks gestation. Fundal height measurements were obtained by the same examiner immediately before and immediately after each subject voided. Examiners were blinded to fundal height measurements and the amount of urine voided. Prevoid fundal height measurements were significantly larger than postvoid fundal height measurements. The differences between pre- and postvoid fundal height measurements varied from -2.8 to 4.6 cm (mean 0.63 cm, SD 1.26). Postvoid fundal height measurements were smaller than the prevoid measurements in 69.5% of the women, and 34.5% of the differences were greater than 1.0 cm. Women who had voided within 30 min before measurement had significantly smaller differences between pre- and postvoid fundal height measurements (n = 20, mean 0.16, SD 1.22) than women who voided more than 30 min before measurement (n = 179, mean 0.68, SD 1.27). These findings indicate that women should be instructed to void within 30 min before fundal height measurements are obtained.

Pulsatile oxytocin for induction of labor: a randomized prospective controlled study.

In a prospective randomized study, 20 patients with term pregnancies underwent induction of labor with either continuous or pulsed (every 8 minutes) intravenous oxytocin infusion. There were no significant differences with respect to induction-labor interval, induction-delivery interval, cesarean section rates, need for pain relief and Apgar scores. Sixty percent of patients receiving continuous oxytocin infusion developed uterine hyperstimulation but only 10% receiving pulsed oxytocin did so. However, the difference was not significant. The mean +/- SEM total amount of oxytocin given by continuous infusion was 4237 +/- 1066 mU which was 70% more than by pulsatile infusion (2454 +/- 808 mU). The highest rate of oxytocin infused was significantly lower by pulsatile administration (5.2 +/- 0.8 mU/min) than by continuous infusion (9.2 +/- 1.8 mU/min, p = less than 0.05). Our study demonstrates that pulsed administration of oxytocin every 8 minutes is as effective and safe as continuous intravenous infusion of oxytocin for induction of labor, requires less oxytocin with therefore, a wider margin of safety and is consistent with the pulsatile release of oxytocin during normal labor.

Hormones and cervical ripening: dehydroepiandrosterone sulfate, estradiol, estriol, and progesterone.

Fetal adrenal steroids have been shown to be important in the timing of parturition. Since dehydroepiandrosterone sulfate is converted to estrogen, which is important in cervical softening, levels of dehydroepiandrosterone sulfate together with those of estradiol, estriol, and progesterone were measured and compared in pregnant women undergoing induction of labor with ripe and unripe uterine cervices. While there were no differences between the levels of estradiol, estriol and progesterone in the two groups of women, dehydroepiandrosterone sulfate was significantly elevated in the group of women with ripe cervices. These findings suggest that cervical changes preceding the onset of labor are associated with a significant elevation of maternal dehydroepiandrosterone sulfate levels. Changes in maternal plasma estradiol, estriol, and progesterone levels do not appear to be clinically related to cervical ripeness.

Breast massage to obtain contraction stress test.

A standard contraction stress test (CST) is usually obtained by the intravenous infusion of exogenous oxytocin for 1 to 3 hours. To assess whether breast massage could elicit a CST, 30 high-risk pregnant women between 37 and 44 weeks gestation massaged their breasts with mineral oil for a maximum of 40 to 60 minutes. Of the 21 patients (70%) who met the CST criterion, 15 had at least one spontaneous uterine contraction in the 20 minutes preceding breast massage, p = .05. Thirty-three percent of those who met the CST criterion did so within 10 minutes of the start of breast massage, and 95% met the criterion within 40 minutes. Other factors, including weeks gestation, parity, overstimulation, and fetal heart rate deceleration that could reasonably influence the effectiveness of the procedure are discussed. Breast massage appears to be an effective method for meeting the CST criterion.

Configuration of the fetal electrocardiogram in ambulatory women in labor monitored with wideband telemetry.

The fetal electrocardiogram (ECG) in 23 ambulatory women in labor was monitored successfully with a single-channel FM telemetry unit with a 0.5-100-Hz wideband receiver to improve the quality of the ECG complex. An inverted QRS complex was seen in a patient with a deceleration and an inverted T wave during a deceleration in a patient confined to bed. A maternal artifact was transmitted in a third. The ECG complex was identical when wired patients were switched to telemetry. Thus, fetal heart rate and ECG configuration can be monitored accurately in ambulatory pregnant women.

Operative ultrasonography in the biliary tract during pregnancy.

Operative roentgenographic cholangiography entails problems during pregnancy because of the hazard of radiation to the fetus and mother. In 450 biliary tract operations in which real-time B-mode operative ultrasonography was performed, five were for diseases of the biliary tract during pregnancy. Operative ultrasound correctly revealed non-palpable stones in the gallbladder in one patient and in the common bile duct in three patients. Furthermore, operative ultrasound provided anatomic information, such as dilation or stenosis of the common bile duct. Of seven possible occasions in which roentgenography would customarily be expected to be performed, operative cholangiography was used only once. Thus, ultrasound significantly reduced the number of operative roentgenographic studies. Operative ultrasonography was not associated with any complications and significant time delays. It is concluded that operative ultrasonography can replace operative roentgenographic cholangiography as a screening procedure for gallbladder and common duct calculi at biliary tract operations during pregnancy.

Single ultrasonic estimation of fetal weight in utero compared with birth weight.

A single ultrasonic determination of fetal weight in utero was made in 270 singleton pregnancies. Infants were divided by birth weights into two groups, less than and greater than the 50th percentile. Ultrasonically determined fetal weight correlated with birth weight (R2 greater than or equal to 0.52) beyond 33 weeks' gestation. Mean fetal weights measured by ultrasound at various stages of gestation correlated well with published values.

Tocolysis with terbutaline sulfate in patients with placenta previa complicated by premature labor.

Six patients with placenta previa complicated by premature labor underwent tocolysis with terbutaline sulfate. The average prolongation of pregnancy was 3.5 weeks. Five patients were at 31 weeks' gestation or more at the initiation of tocolytic therapy and had infants who survived and were greater than 2,000 gm at birth. All patients received an average blood transfusion of 6.7 units of packed cells each.

Mechanical behavior of fetal dura mater under large axisymmetric inflation.

The nonlinear mechanical behavior of fetal dura mater was tested experimentally and compared to two published nonlinear material strain energy functions, the Mooney-Rivlin and the Skalak, Tozeren, Zarda, and Chien (STZC). The STZC constitutive relations best fit the behavior of the dura mater and were used to describe quantitatively its stiffness. Runge-Kutta numerical procedures were used to fit the theoretical data to the experimental results. The material's stiffness was positively correlated with fetal weight (r = 0.67, p less than 0.05). These results are discussed and directions for future research indicated.

Pregnancy termination in patients with pregnancy-induced hypertension or eclampsia at less than 22 weeks' gestation.

PIP: 3 patients with fetal death, 2 of whom had pregnancy-induced hypertension and a third with eclampsia had pregnancy termination before 22 weeks' gestation with vaginal prostaglandin E2 (PGE2) suppositories, without complication. PGE2 has a hypotensive action, decreasing blood pressure by arteriolar dilation and blocking the angiotensin-induced rise in blood pressure in the pregnant rhesus monkey and should be useful abortifacient in patients with hypertension including preeclampsia and eclampsia. One patient received magnesium sulfate and the other 2 received hydralazine and methyldopa during PGE2 administration which could alter mean arterial pressure (MAP). MAPs remained stable and dropped slightly after PGE2 administration in the 2nd and 3rd patients. These outcomes suggest that PGE2 suppositories can be used to terminate 2nd trimester pregnancy in cases of hypertension and eclampsia when routine medical management is ineffective or when fetal death occurs although caution is advised since severe hypotension can occur with PGE2 administration.^ieng

Maternal psychological and physiologic correlates of fetal-newborn health status.

Data were obtained from 32 primigravid women in pregnancy and in labor. Anxiety in labor, measured by a self-report inventory, and plasma epinephrine were significantly correlated with the fetal heart rate pattern in active-phase labor (3 to 10 cm of cervical dilatation). The fetal heart rate pattern was significantly correlated with Apgar scores at 1 and 5 minutes. Conflict in the acceptance of pregnancy, measured in prenatal interviews, predicted anxiety and epinephrine levels in labor and the 5-minute Apgar score.