Gestational age at cervical length measurement and preterm birth in twins.

OBJECTIVES: To estimate the risk of preterm delivery of twin pregnancies based upon sonographic cervical length measurement and gestational age at measurement. METHODS: Twin pregnancies that delivered between 1999 and 2005 and that underwent sonographic measurement of cervical length between 13 and 34 + 6 weeks' gestation were identified and a retrospective review performed. Women with anomalous pregnancies, multifetal reduction, cerclage placement or medically indicated deliveries before 35 weeks were excluded. Logistic regression analysis was used to estimate the risk of preterm delivery before 35 weeks. RESULTS: A total of 561 women underwent 2975 sonographic cervical length measurements during the study period. The rate of preterm delivery before 35 weeks was 19.4%. The risk of delivery before 35 weeks decreased by approximately 5% for each additional mm of cervical length (odds ratio (OR) 0.95 (95% CI, 0.93-0.97); P < 0.001) and by approximately 6% for each additional week at which the cervical length was measured (OR 0.94 (95% CI, 0.92-0.96); P < 0.001). CONCLUSION: The gestational age at which cervical length is measured is an important consideration when estimating the risk of spontaneous preterm birth in twins. The risk of preterm delivery is increased at earlier gestational ages and as cervical length decreases.

Previous cesarean section and the risk of postpartum maternal complications and adverse neonatal outcomes in future pregnancies.

OBJECTIVE: To assess maternal postpartum and neonatal outcomes associated with previous method of delivery. STUDY DESIGN: We analyzed prospectively collected maternal and neonatal data from July 2002 to December 2003. Data were collected from dedicated perinatal database and neonatal database from discharge and procedure codes. Groups were: (i) multiparous, prior vaginal delivery (VD), and (ii) multiparous, prior cesarean (CS). This group was subdivided by subsequent pregnancy trial or no trial of labor (No TOL). Results were compared with chi (2)-analysis; significance P<0.05. RESULTS: There were 17 406 births. Prior CS patients without trial of labor (TOL) required more blood transfusions, intensive care unit admissions and hospital readmissions than women with a prior VD. Prior CS patients with TOL required more aminoglycosides for postpartum infection. Term neonates of (CS) mothers without a TOL were more likely to have prolonged hospitalization and require ventilatory support. CONCLUSIONS: In their subsequent delivery, women with a prior CS delivery are at significant risks for postpartum maternal and neonatal morbidities compared with parous patients who experienced a prior VD.

Lowering the cesarean section rate in a private hospital: comparison of individual physicians' rates, risk factors, and outcomes.

OBJECTIVE: Our purpose was to compare the practice patterns and outcomes of physicians delivering in our institution to identify risk factors and management techniques that could explain the differences in individual cesarean section rates. STUDY DESIGN: We retrospectively reviewed detailed computerized delivery records (n = 16,230) collected from May 16, 1988, to July 30, 1995. We excluded physicians who had <100 deliveries at our institution during the study period. The physicians were divided into two groups depending on whether their individual cesarean section rates were greater than (control group) or less than 15% (target group). Various cesarean section rates, risk factors for abdominal delivery, labor management techniques, and neonatal outcome parameters were calculated for each group. The cesarean section rates of the two groups were analyzed by year to assess changes. RESULTS: As expected by study design, the overall cesarean section rate was markedly different between the two groups (13.8% vs 23.8%). In addition, the primary, repeat, primigravid, and multiparous cesarean section rates were all lower for the target group. The rates of cesarean section for fetal distress (1.5% vs 3.3%) and cephalopelvic disproportion (5.3% vs 8.5%) were also significantly less in the target group. The rates of breech presentation, third-trimester bleeding, and active herpes cesarean sections were not lower. The control group had more postterm (8.6% vs 14.7%) and >4000 gm infants (12.0% vs 13.7%) but similar numbers of low birth weight, multiple gestation, and preterm infants. The target group used more epidural anesthesia, oxytocin induction, and trial vaginal births after cesarean delivery and more successful trial vaginal births after cesarean sections. Over the study period the cesarean section rate in the target group remained unchanged, whereas it steadily declined in the control group. CONCLUSIONS: Individual physician's lower cesarean sections are primarily obtained by labor management and attempting vaginal birth after cesarean delivery. These practice patterns did not appear to lead to any increase in perinatal morbidity or mortality. Efforts to lower cesarean section rates of individual practitioners should focus on the areas of fetal distress, cephalopelvic disproportion, and repeat cesarean section.

Advanced maternal age: perinatal outcome when controlling for physician selection.

OBJECTIVE: Our purpose was to determine whether differences in maternal outcome because of maternal age could be controlled by the elimination of bias in physician selection. STUDY DESIGN: We performed a case-control study that compared pregnancy outcomes of 164 patients delivered at our institution at > or = 40 years old with outcomes in a control group consisting of the next two deliveries by the same attending physician of women with ages 20 to 29 years. Retrospective analysis of the antepartum and intrapartum records was done to compare clinical outcome. RESULTS: We observed a significant increased incidence of nulliparous cesarean delivery (p = 0.046), elevated results of glucose screens with a 50 gm load (p = 0.00002), and hypertension throughout pregnancy in the older patients in spite of controlling for physician selection. The older patient group was more likely to have used assisted reproductive techniques (p = 0.000005) and had higher baseline weights (p = 0.001) and maximum pregnancy weights (p = 0.042). However, the neonatal outcome was similar in both groups. Despite controlling for physician selection, we demonstrated increased rates of abdominal delivery, glucose intolerance, and hypertension in older patients. Fetal and neonatal outcomes were similar in both groups. CONCLUSION: Women > or = 40 years old tend to have an increased incidence of a few pregnancy-related complications, even when controlling for physician selection.

Decreasing the cesarean section rate in a private hospital: success without mandated clinical changes.

OBJECTIVE: We analyzed the delivery statistics from our institution to describe a successful program of cesarean section delivery reduction and to help us understand what factors explained the reduction. STUDY DESIGN: A retrospective analysis of various cesarean section rates and risk factors from a prospectively collected delivery database of all patients delivered between May 15, 1988, and June 30, 1994. During the study period we instituted a program of increasing awareness, confidential provider feedback, more aggressive laboring techniques, and other clinical guidelines. The delivery data were divided into 6-month intervals and analyzed by chi 2 tables. RESULTS: The overall cesarean section rate fell from 31.1% to 15.4%. Similar reductions were noted in the primary (17.9% to 9.8%) and repeat cesarean section rates (13.2% to 5.7%). The primary cesarean section rate fall was accompanied by a drop in abdominal delivery for cephalopelvic disproportion and fetal distress. The repeat cesarean section rate is explained by a significant increase in trial and successful vaginal birth after cesarean delivery. No increase in maternal, fetal, or neonatal morbidity or mortality was observed. CONCLUSIONS: We have demonstrated that the cesarean delivery rate can be safely lowered in a private hospital without mandated clinical changes. Our data suggest that careful and detailed feedback can lead to improved clinical practice.

Biometry of the fetal cisterna magna: estimates of the ability to detect trisomy 18.

Measurements of the fetal cisterna magna were obtained from a prospective sample of patients undergoing diagnostic obstetric ultrasound examinations. These normal measurements were then compared to a retrospective sample of ultrasound scans from fetuses with the diagnosis of trisomy 18 by amniocentesis. The fetal cisterna magna increases in size throughout pregnancy. The sample from fetuses with trisomy 18 was different and had a higher rate of small and large cisterna magnas. After the two samples were mixed, it was determined that a cut-off of 2.5 standard deviations for the fetal cisterna magna would give a sensitivity of 26.3%, specificity of 99.1%, positive predictive value of 50.0% and negative predictive value of 97.6% for trisomy 18. The probability that a fetal cisterna magna of abnormal size will predict trisomy 18 in an early second-trimester ultrasound examination with the 2.5 standard deviation cut-off was estimated at 0.019. A fetal cisterna magna that is of abnormal size appears to be of diagnostic value in identifying the fetus with trisomy 18, but its sensitivity is low.

The contraction stress test.

The CST is one of the first forms of fetal surveillance; it is still the only form that tries to use the principle of induced stress to reveal marginal placental insufficiency. With the expansion of biophysical evaluation, there are many choices in antenatal testing. Clearly the CST should not be the only form of testing to follow high-risk pregnancies. However, its proved efficacy and close correlation with intrapartum monitoring make it an essential tool. With nipple stimulation techniques, it is an easy and quick method for evaluating the fetus. Clinicians who follow high-risk pregnancies need to understand fully the administration and proper interpretation of the CST.

Type I fetal cystic adenomatoid malformation of the lung with hydrops at 18 weeks' gestation: a case report.

Fetal cystic adenomatoid malformation, type I, is a rare pulmonary anomaly that has been diagnosed after 20 weeks' gestation. The prognosis of this malformation is usually dependent on whether it is microcystic, types II and III, or macrocystic, type I. We report a case of severe macrocystic fetal cystic adenomatoid malformation diagnosed at 18.4 weeks' gestation. This case demonstrates that fetal cystic adenomatoid malformation can be diagnosed at 18 weeks and that hydrops with oligohydramnios may be part of the natural history of type I lesions this early in pregnancy.

Antepartum fetal surveillance in patients with diabetes: when to start?

OBJECTIVE: Although antepartum fetal well-being testing is an accepted practice in the management of diabetic patients, there are few data suggesting when to start. Our goal was to examine when testing should be started in the pregnant diabetic woman. STUDY DESIGN: Antepartum test results and patient histories were prospectively collected on all diabetic pregnancies from January 1981 through December 1991. The data were retrospectively analyzed for when fetal compromise became evident. Fetal compromise was defined as stillbirth, first positive contraction stress test, or intervention because of an abnormal antepartum fetal test result. RESULTS: Six hundred fourteen patients were enrolled in the study. There were three stillbirths, 45 (7.4%) patients had at least one positive contraction stress test, and 71 (11.6%) patients were delivered because of an abnormal fetal test result. Those with early compromise (< or = 34 weeks' gestation) could not be identified solely by diabetic class. The majority of patients (73%) requiring early intervention because of an abnormal test were class R or F diabetic patients with a growth-retarded fetus or were patients who had a concomitant diagnosis of hypertension. CONCLUSIONS: Class R or F diabetic patients or diabetic patients with a growth-retarded fetus or a concomitant diagnosis of hypertension may require testing to be started as early as 26 weeks' gestation. Otherwise, testing may be safely delayed until 32 weeks' gestation.

How frequently should the amniotic fluid index be repeated?

OBJECTIVE: Our objective was to determine the most appropriate interval for assessing amniotic fluid volume with amniotic fluid index. STUDY DESIGN: In a retrospective analysis amniotic fluid indexes performed every 3 to 4 days in antepartum testing patients were compared with their follow-up values. Of 10,742 amniotic fluid indexes there were 7393 with follow-up values within 4 days. The results were stratified by current amniotic fluid index, gestational age, and concurrent nonstress test results. The groups were compared with chi 2 analysis. RESULTS: Patients with normal amniotic fluid index (> or = 8 cm) had a 0.54% chance of oligohydramnios developing in the next 4 days. Those patients with low normal amniotic fluid indexes (5 to 8 cm) had a 5% chance of oligohydramnios developing within the next 4 days, and patients with low amniotic fluid indexes (< or = 5 cm) had a 59% chance of persistent oligohydramnios 4 days after the index examination. Subdividing by gestational age demonstrated that patients > or = 41 weeks' gestation had a 2.6% chance of oligohydramnios developing within 4 days if current amniotic fluid index was between 8 and 15 cm. Results of concurrent fetal heart rate findings did not appear to change the risk for development of oligohydramnios. CONCLUSION: In patients < 41 weeks' gestation with normal amniotic fluid indexes, a repeat amniotic fluid index is not necessary for 7 days.

Antepartum testing in the hypertensive patient: when to begin.

Antepartum testing has been recommended for patients whose pregnancies are complicated by hypertension. Although this is considered accepted practice, there are little data available to help the clinician know when to start testing. To help answer this question in patients with chronic hypertension and nonproteinuric pregnancy-induced hypertension, we reviewed the results of all antepartum tests between 1976 and 1987 in patients with these diagnoses. The primary mode of surveillance in the majority of our patients was the contraction stress test. We determined when patients first had positive contraction stress test results and when intervention occurred because of an abnormal antepartum test result. There were a total of 917 patients tested with these diagnoses. Fifty-three (5.8%) of these patients had at least one positive contraction stress test result. Twenty-two patients were delivered of infants before 35 weeks' gestation because of abnormal antepartum test results. Those with early intervention (less than 35 weeks' gestation) could not be differentiated from those with later intervention (greater than or equal to 35 weeks' gestation) by maternal age, diastolic blood pressure, or systolic blood pressure at the time of testing. The majority of patients who were delivered of infants before 35 weeks' gestation had a concomitant diagnosis of systemic lupus erythematosus, intrauterine growth retardation, diabetes mellitus, or superimposed preeclampsia. On the basis of when compromise was evident, patients with these diagnoses may require testing to be started as early as the fetus is considered viable. However, in those without these diagnoses, the clinician may delay the beginning of testing until 33 weeks' gestation without significant risk of pregnancy loss before testing.

Unexplained fetal baseline bradycardia in congenital panhypopituitarism.

An unexplained fetal baseline bradycardia apparently not secondary to uteroplacental insufficiency is reported. Congenital panhypopituitarism was diagnosed in the neonate. A common cause of both findings is speculated and a review of possible methods for antenatal diagnosis is given.

Management of postdate pregnancy.

Management of the problems associated with pregnancies that extend beyond 294 days of amenorrhea has become increasingly important in obstetrics. This article outlines some of the methods that minimize the risks to the mother, fetus, and neonate in postdate pregnancy. A brief description of the definitions, incidence, and impact of postdate pregnancy is given for a baseline on which to base management decisions. The current management techniques are then given for the following aspects: diagnosis, antepartum surveillance, timing of delivery, and intrapartum management. Finally a synopsis of research areas that may change management is given.

Accuracy of serum human chorionic gonadotropin concentrations and ultrasonic fetal measurements in determining gestational age.

Prior to 60 days' gestation, the maternal serum concentration of human chorionic gonadotropin (hCG) can predict the estimated date of confinement, but later in pregnancy, hCG concentrations vary widely. The current study was performed to compare the accuracy of hCG measurements with other determinants of gestational age. Fifteen patients in whom gestational age was documented were monitored prospectively throughout pregnancy. One to two determinations of hCG (beta subunit) were obtained during the first 60 days. Then, ultrasonographic measurements of crown-rump length were obtained between 8 and 16 weeks' gestation and two measurements of biparietal diameter were performed between 18 and 32 weeks. These results were compared to actual dates of gestation. The mean (+/- SD) difference between gestational age predicted by single measurements of hCG and actual gestational age was 3.2 +/- 2.5 days (r = 0.94, p less than 0.0001), which compared favorably with estimates by crown-rump measurements (6.7 +/- 6.5 days) and measurements of biparietal diameter (6.3 +/- 5.3 days). These results demonstrate that hCG measurements during the first 60 days accurately predict gestational age and complement ultrasonic determinations of gestational age used later in pregnancy.

Determination of gestational age by serum concentrations of human chorionic gonadotropin.

To examine the accuracy and predictability of human chorionic gonadotropin concentrations in determining gestational age, serum concentrations of human chorionic gonadotropin (beta-subunit) were measured during the first 157 days after last menses. Using the regression curve generated, human chorionic gonadotropin concentrations obtained during the first 60 days accurately predicted the day of gestation. The difference (mean +/- SD) between the human chorionic gonadotropin-predicted estimated date of confinement and the estimated date of confinement established by known dates of last menses was 3.1 +/- 2.3 days. In patients followed to parturition, the difference between human chorionic gonadotropin-estimated gestational age and gestational age by physical assessment of the neonate was 8.1 +/- 7.1 days. After 60 days' gestation, human chorionic gonadotropin concentrations vary widely and are of little value in predicting gestational age. In addition to documenting conception, early human chorionic gonadotropin determinations accurately date the gestation and complement other clinical and biophysical methods for determining gestational age that are frequently used later in pregnancy.