Mitral valve-tricuspid valve distance as a sonographic marker of trisomy 21.

OBJECTIVE: Pathologic studies suggest that a decreased mitral valve-tricuspid valve distance (MTD) is found in trisomy 21 fetuses without cardiac defects. We assessed the feasibility of using the MTD as a second-trimester sonographic marker for trisomy 21. METHODS: We performed a retrospective case-control study of all cases of trisomy 21 at our institution from 1998 to 2008. Cases without a prenatally identified cardiac defect and with adequate images from 15 to 26 weeks' gestation were assessed. The distance between the medial insertions of the mitral and tricuspid valves (i.e. the MTD) onto the ventricular septum was obtained. We also obtained the MTD from normal controls during the study period. Multiple linear regression analysis was used to assess the effects of gestational age and trisomy 21 on MTD. Gestational age-specific percentiles and multiples of the median were calculated, and curves were fitted using linear regression analysis. RESULTS: We identified 57 trisomy 21 fetuses with a measurable MTD and compared these with 634 control fetuses. Multiple linear regression analysis revealed a positive correlation between MTD and gestational age and a negative correlation between trisomy 21 and MTD. Using a cut-off of the 5(th) percentile, the MTD detected 70% of trisomy 21 cases with a 3.8% false-positive rate in the controls. CONCLUSIONS: The MTD increases with gestational age and is lower in fetuses with trisomy 21. Twenty (35%) of the 57 cases had no sonographic marker of trisomy 21 except an MTD below the 5(th) percentile for gestational age. The MTD was a useful independent marker for trisomy 21 in the second trimester.

Sonographic birth-weight prediction in obese patients using the gestation-adjusted prediction method.

OBJECTIVES: Ultrasound birth-weight prediction may be more accurate if assessed at 34 to 36 + 6 weeks' gestation and extrapolated using the gestation-adjusted projection (GAP) method than if done at term. Because ultrasound is less accurate in women with elevated body mass index (BMI), we assessed the accuracy of GAP birth-weight prediction in obese as compared to non-obese women. METHODS: We performed a retrospective review of 1382 women with singleton pregnancies who had undergone fetal ultrasound examination at between 34 + 0 and 36 + 6 weeks, subclassified by pre-pregnancy BMI. Analysis of variance was used to compare predicted and actual birth weight. RESULTS: 1025 controls and 357 obese women were included. The obese women were divided by BMI: 159 in Class I (BMI, 30-34.9 kg/m(2)); 105 in Class II (BMI, 35-40 kg/m(2)) and 93 in Class III (BMI > 40 kg/m(2)). Mean systematic (percent) birth-weight prediction error was within 4% for all groups, with a 95% error range between - 5% and + 5%. The GAP method was able to predict actual birth weight within 20% for all groups in over 90% of cases. For all groups, the GAP method correctly excluded the presence of macrosomia with >or= 90% specificity. Negative likelihood ratios for the prediction of macrosomia were between 0.4 and 0.6 for all groups, regardless of obesity. CONCLUSIONS: The GAP method of birth-weight prediction using ultrasound measurement at 34 to 36 + 6 weeks predicts birth weight within 20% error in over 90% of cases, and is able to exclude macrosomia with over 90% accuracy regardless of maternal BMI.

Pumps and warmers during amnioinfusion: is either necessary?

OBJECTIVE: To determine if there is evidence from published reports that the use of infusion pumps or solution warmers during amnioinfusion is beneficial. DATA SOURCES: We identified all English-language amnioinfusion reports published since 1983 through Medline and references. METHODS OF STUDY SELECTION: Fourteen prospective papers with at least 40 subjects were identified. DATA EXTRACTION AND SYNTHESIS: For the amnioinfusion and control groups in each study, odds ratios (OR) were calculated for cesarean delivery, fetal distress, meconium below the cords, low 5-minute Apgar score, and endometritis. Cumulative ORs were calculated using the Mantel-Haenszel inverse variance method. This process was repeated after separation into pump-gravity and warmed-unwarmed groups. Multiple regression analyses were performed. Amnioinfusion improved the ability of the fetus to tolerate labor (fetal distress OR 0.40), decreased the incidence of meconium below the cords (OR 0.16), and decreased the rate of cesarean delivery (OR 0.56). There were no demonstrable benefits associated with the use of warmers or pumps. In multiple regression analysis, infusion pumps were associated with a significantly increased risk of fetal distress (P = .01). CONCLUSION: The use of amnioinfusion is associated with a decreased risk of fetal distress, meconium below the cords, and cesarean delivery. To date, there is no demonstrable benefit using infusion pumps or solution warmers during amnioinfusion.

Cost-effectiveness of routine antenatal varicella screening.

OBJECTIVE: To evaluate the cost-effectiveness of routine antenatal varicella serologic screening of pregnant women with negative or indeterminate varicella histories. METHODS: Routine antenatal varicella screening was evaluated using a decision analytic model. Outcomes were varicella cases, deaths, and life-years. Probabilities were derived from the literature, and sensitivity analysis was performed when data were imprecise or subject to variation. The analysis was repeated to include the effect of a policy of routine screening and vaccination of all adults. RESULTS: Routine antenatal varicella screening of history-negative women was not cost-effective unless the cost of screening was decreased six-fold, varicella exposure rates were greater than 6%, or there was a greater than three-fold decrease in varicella exposure in women testing nonimmune compared with unscreened women. These results were not sensitive to alterations in varicella-zoster immunoglobulin (Ig) effectiveness, varicella communicability, rates and timing of contact reporting, costs (per case, pneumonia, and death), or serologic test performance. If performed as part of a policy of universal screening of all history-negative adults (with vaccination of the majority of those testing nonimmune), routine antenatal varicella testing became cost-effective. CONCLUSION: Routine antenatal varicella screening of all pregnant women with negative or indeterminate varicella histories is not cost-effective. It could be cost-effective in groups of women with increased exposure risk, or if part of a policy of screening and vaccination of all adults.

Pregnancy complicated by thrombocytopenia secondary to human immunodeficiency virus infection.

BACKGROUND: Human immunodeficiency virus (HIV)-positive pregnant women may manifest thrombocytopenia similar to that of immune thrombocytopenic purpura (ITP), putting the fetus at risk of thrombocytopenia and hemorrhage. Whereas the fetal platelet count can be assessed in cases of ITP, there is no safe way to evaluate it during HIV-positive pregnancy without risking fetal inoculation with HIV. CASE: A pregnant woman with HIV-associated autoimmune thrombocytopenia was treated on several occasions with immune globulin and prednisone. Because of the inability to assess the fetal platelet count owing to the risk of fetal inoculation with maternal HIV, a primary cesarean was performed at term. The neonate was thrombocytopenic at birth. CONCLUSION: Because of the risk of fetal thrombocytopenia and the inability to evaluate fetal platelet counts safely (without resorting to invasive procedures that may increase the risk of fetal HIV infection), women with HIV-associated autoimmune thrombocytopenia should be delivered by cesarean.

Prenatal sonographic diagnosis of non-rhizomelic chondrodysplasia punctata.

BACKGROUND: Chondrodysplasia punctata is a rare heterogeneous group of bone dysplasias occurring with an incidence of one in 100,000 live births. Prenatal sonographic diagnosis of non-rhizomelic chondrodysplasia punctata (Conradi-Hünermann syndrome) has previously been reported only following detection of overall limb shortening. CASE: Multiple sonographic skeletal findings of premature epiphyseal calcifications, other unusual calcifications, kyphoscoliosis, and asymmetrical limb shortening, typical of non-rhizomelic chondrodysplasia punctata, led to second-trimester prenatal sonographic diagnosis of this condition. CONCLUSION: Second-trimester prenatal sonographic diagnosis of premature epiphyseal calcifications associated with non-rhizomelic chondrodysplasia punctata is possible.

Reproductive toxicology of alkylating agents.

Alkylating agents have been used during childhood and in reproductive age groups for the treatment of malignancy or collagen-vascular disease. Because of their mechanism of action, alkylating agents have the ability to interfere with chromosomal structure, ovarian function, spermatogenesis, and embryogenesis. Teratogenic risks have been established in animal studies, although are less clear for humans. Total dose, timing of administration, and age of the patient at the time of therapy are all factors in determining adverse effects. If possible, alkylating agents should be avoided in the first trimester, but can be used during the remainder of pregnancy.

Active management of labor: a meta-analysis of cesarean delivery rates for dystocia in nulliparas.

The objective of this article is to determine through meta-analysis of published literature whether active management of labor lowers the cesarean delivery rate for dystocia in nulliparas. Using MEDLINE and reference citations to 1966, 18 published reports in English on active management of labor were identified. Selection criteria for five selected studies included: tenets of active management followed, detailed description of patient selection and analysis, numerical data on cesarean deliveries for dystocia in nulliparas, and use of a control group. Data on cesarean deliveries performed on nulliparas for dystocia were abstracted onto 2 x 2 tables by both authors independently (one blinded to study authors, journal, institution, and conclusions), and quality ratings independently assessed. Differences were resolved by consensus. Individual odds ratios were calculated, with summary odds ratios and 95 percent confidence intervals determined using the Mantel-Haenszel method. Including the three highest quality studies (two randomized, one nonrandomized), there was a 34 percent decrease in cesarean delivery rates associated with active management (OR 0.66, 95 percent CI 0.54-0.81), without an increase in adverse neonatal outcome (OR for cesarean for non-reassuring fetal heart rate monitoring 0.91, 95 percent CI 0.68-1.22). Active management of labor is associated with a 34 percent decrease in the rate of cesarean delivery for dystocia in nulliparas. Along with the expected subsequent decrease in numbers of candidates for trials of labor, the decline in total cesarean deliveries over the entire population directly or indirectly attributable to active management is 13 percent.

Percutaneous balloon valvuloplasty for severe mitral stenosis during pregnancy: a review of therapeutic options.

A woman presented at 29 weeks' gestation with previously undiagnosed severe mitral stenosis. She did not respond to medical therapy, and underwent successful percutaneous balloon mitral valvuloplasty with complete resolution of her symptoms. The remainder of her pregnancy was uncomplicated, and she delivered a healthy infant at 40 weeks' gestation. Percutaneous balloon valvuloplasty offers an innovative alternative to standard surgical therapy if medical management is unsuccessful.

Does progesterone potentiate the in vitro effect of cocaine on papillary myocardium in Long-Evans rats?

Cocaine's cardiotoxicity was reported in our laboratory to be augmented by progesterone. This study was designed to replicate these findings and determine the mechanism. Rats were pretreated with progesterone (study) or vehicle (control). Papillary muscles were attached to transducers in Krebs' baths. Paced contractility parameters were measured while increasing concentrations of cocaine, norepinephrine, or tetrodotoxin were added. In nine baths, yohimbine was added before the cocaine. Twelve rats were pretreated with reserpine, and cocaine added to the baths. In muscles from nonreserpinized control rats, there was a small positive inotropic effect (8.6% above baseline) at 10(-6) M cocaine, not seen in study muscles. There were no differences between study and control muscles in cocaine concentrations at which muscles became acontractile, nor in responses to norepinephrine, tetrodotoxin, or to cocaine after the addition of yohimbine or following reserpine pretreatment. We could not replicate cocaine's previously reported increased negative inotropic effect in progesterone-treated rats, nor was there evidence supporting possible mechanisms for this reported effect.

Norplant use among urban minority women in the United States.

The aim of this study was to develop a profile of urban American women who chose Norplant(R), determine factors associated with retention and early termination of implants, and to determine reasons for early removal. A total of 197 adult black and Hispanic women who had Norplant inserted were followed prospectively for up to 5 years. Interval and cumulative termination rates were calculated. Data were stratified by race and analyzed to include lost-to-follow-up (LTFU) subjects. Multivariate survival analysis was used to determine variables independently associated with termination. Cumulative continuation rates were 68% after year 1 and 13% after year 4. Significant predictors of retention included black race and lower parity. Probability of early termination increased with higher parity and Hispanic race. For black subjects, recent use of hormonal contraception was a predictor of retention. Menstrual changes and weight concerns were common reasons for removal. The Norplant 1-year continuation rate is lower than previously reported, but is higher than reported for oral contraceptives and Depo-Provera(R). Future studies should stratify by age, race, and parity, and use standardized terminology to report intervals of use.

Cocaine LD50 in Long-Evans rats is not altered by pregnancy or progesterone.

Progesterone increases cocaine's cardiovascular toxicity in sheep and rats. To determine whether progesterone enhances the lethality of cocaine, nonpregnant female rats were treated with either IM progesterone (P4) or vehicle, and pregnant rats (Preg) were untreated. The rats received one IP injection of cocaine at a dose between 25-75 mg/kg and were observed for seizures and/or death. All 62 rats that died did so within 17 min, preceded by seizures in 90.3%. Mean times-to-seizure and times-to-death, and mean lethal serum cocaine concentrations did not differ among groups. Serum progesterone levels (ng/ml +/- SEM) at the time of death were different among groups: 24 +/- 1.7 (C), 102 +/- 6.4 (P4), and 139 +/- 5.2 (Preg). Logistic regression dose/fatality curves, LD50s, and LD10s for the pregnant, progesterone, and control groups were not significantly different from one another. Though progesterone has enhanced cocaine's cardiac toxicity in some studies, it does not increase the risk of death from acute cocaine exposure in rats.

Contraceptive implant use among inner city teens.

PURPOSES: This study develops a clinical profile of urban teens who selected Norplant for contraception; determines which variables identify the subjects most likely to be compliant with the method; and determines the most common reasons for early termination of use. METHODS: Demographic and health history data and reasons for termination of use were collected prospectively for 122 inner city teens who received Norplant. Life table analysis and the Mantel-Haenszel procedure were used to investigate differences between Norplant retainers and terminators. RESULTS: The sample consisted of black and Hispanic teens between the ages of 13-19 years, the majority of whom had one or more children and were in school. One and two year retention rates were 71% and 62%. The highest removal rates occurred during the 3-6 month interval after insertion. A significant finding was that teens who have experienced induced abortion were more likely to retain Norplant. Common reasons for termination of use included general and social concerns, including pregnancy desire. CONCLUSIONS: Norplant retention rates for this teen sample were greater than the compliance rates reported for other conventional methods. Similar to noncompliance with oral contraceptives, discontinuance of the method was most likely to occur in the first 6 months of use. A history of induced abortion identifies those teens most likely to retain Norplant, suggesting that these teens might evaluate contraceptive risks and benefits differently than those with no abortion history. Pregnancy desire was a common reason for terminating Norplant use.

PIP: This prospective study of 122 Black and Hispanic inner-city adolescent Norplant users recruited from a teen clinic in Rochester, New York, was the first to include a two-year follow-up period. The study period extended from June 1, 1991, to June 30, 1993. The mean age of Norplant acceptors was 17.4 years; 76% had a parity of at least one. Recorded was a one-year retention rate of 71% and a two-year rate of 62%. The greatest number of removals occurred in the first three months after insertion. There was no association between Norplant retention and age, weight, race, parity, or school status. The only significant predictor of Norplant continuation was a history of at least one induced abortion. The reasons most frequently cited by the 30 adolescents who discontinued Norplant were headache, fatigue, hair loss, nausea, weight changes, breast symptoms, and appetite changes. Menstruation irregularities were reported only by terminators in the 3-6 month use interval. Considering the high continuation rates recorded in this survey and the method's proven effectiveness, Norplant has the potential to widen substantially the birth interval between adolescent pregnancies.

Comparison of paracervical block techniques during first trimester pregnancy termination.

OBJECTIVES: To determine whether variations in chloroprocaine placement in paracervical blocks influence effectiveness, whether chloroprocaine is superior to saline, and what factors influence pain perception. METHOD: Eighty-two women undergoing first trimester aspiration abortions were randomized to receive 1% chloroprocaine or saline at 3-5-7-9 or 4-8 o'clock positions. Using a 0--10 scale, women rated anxiety, dysmenorrhea, and pain associated with laminaria insertion, paracervical block, and aspiration. RESULTS: All four groups were similar in medical and demographic characteristics. Injection position did not influence pain ratings, but women who received chloroprocaine had less pain than those who received saline (6.3+/-2.3 vs. 7.8+/-2.0, P=0.002). Paracervical pain and dysmenorrhea were independently associated with aspiration pain scores (respective regression coefficients 0.49 and 0.26, P<0.008). CONCLUSIONS: There is no advantage to using a four-site paracervical block over a two-site technique, but chloroprocaine is superior to saline. Paracervical block may not provide adequate anesthesia during first trimester abortion, especially for women with significant dysmenorrhea.

Obstetrical issues in substance abuse.

Substance abuse complicates between 10% and 25% of pregnancies, and has been associated with increased perinatal morbidity and mortality. The mechanisms of action of certain drugs predispose to specific types of complications, but the explanations for obstetrical effects of other drugs are more obscure. It is often difficult to differentiate the effects of drugs from the socioeconomic issues surrounding the drug abuser. There is no doubt, however, that the infants of pregnant drug abusers suffer from increased risks of low birthweight, preterm delivery, possible teratogenic effects, fetal dependence and withdrawal, and possible neurobehavioral effects. Health-care providers must encourage these patients to seek prenatal care early and to continue care throughout pregnancy. With a coordinated system for antenatal monitoring and support, these risks hopefully can be decreased and the perinatal outcome improved.

Screening and treatment of bacterial vaginosis during pregnancy: a model for determining benefit.

Bacterial vaginosis is associated with an increased risk of preterm birth. The treatment of bacterial vaginosis has recently been shown to decrease the risk of preterm delivery, especially in high-risk populations. However, the benefit of routine screening and treatment in the general population is uncertain. Using the information from several recent studies, a graph and nomogram generated from a mathematical model allow the obstetrician to determine the benefit of routine screening and treatment of bacterial vaginosis in his or her obstetrical population, depending on the prevalence of bacterial vaginosis and the total preterm delivery rate in that obstetrician's practice. If the prevalence of bacterial vaginosis and the incidence of preterm delivery are low, then routine screening would be expected to prevent small numbers of preterm births, and therefore may not be cost-effective.

Cesarean delivery risk adjustment for regional interhospital comparisons.

OBJECTIVE: The aim of this study was to determine the effect of adjustment for patient population mix on observed, expected, and standardized cesarean delivery rates in regional hospitals. STUDY DESIGN: Multiple logistic regression was applied to a large regional perinatal database comprising 16 hospitals. Variables significantly associated with cesarean delivery were used to calculate cesarean delivery probabilities for individual patients. Probabilities were summed across hospitals to derive expected hospital cesarean delivery rates. A standardized rate for each hospital was then calculated by dividing the observed rate by the expected rate and multiplying by the regional rate. RESULTS: The regional cesarean delivery rate was 21.9% for 6798 women. Observed hospital rates varied from 17.1% to 39.2%. Twenty-two variables were associated with cesarean delivery. Expected cesarean delivery rates ranged from 18.1% to 26.0%. Among the 5 hospitals with the lowest observed cesarean delivery rates only 2 had rates significantly lower than those of the rest of the region, and only 1 of those 2 rates remained significantly lower after adjustment. One other hospital that had an adjusted rate significantly lower than the crude rate had not appeared statistically different from the rest of the region before standardization. Among the 5 hospitals with the highest cesarean delivery rates, 4 had rates significantly higher than the rest of the region, and 3 of them had significantly higher observed rates than expected rates. CONCLUSIONS: Compared with using observed (crude) cesarean delivery rates, adjustment for differences in patient risk factor mix facilitates more accurate comparison of cesarean delivery rates among hospitals within a region.

Concepts and controversies in the management of group B streptococcus during pregnancy.

BACKGROUND: Group B beta-hemolytic streptococcus colonizes 20 percent of pregnant women. Intrapartum fetal colonization leads to invasive disease in 1 to 2 infants of every 1000 births in the United States, and has a mortality of approximately 6 percent. Several protocols using intrapartum chemoprophylaxis have been devised to improve management of the disease, but confusion continues about details and implementation. This review examined the clinical issues, current management protocols, and advantages and disadvantages of these protocols for group B streptococcus. METHODS: We reviewed the literature and described the epidemiology, detection methods, risk factors, neonatal disease potential of group B streptococcus, and the historical development of management protocols. Two current alternatives, the American College of Obstetricians and Gynecologists' risk-based protocol and the Centers for Disease Control and Prevention's screening-based protocol, are described and compared. RESULTS: The risk-based protocol does not entail antepartum screening, but treats women with certain risk factors during labor. The screening-based protocol includes cultures at 35 to 37 weeks' gestation, and offers intrapartum prophylaxis to all women with positive cultures. Uncultured women with risk factors are treated. Both protocols involve high rates of intrapartum antibiotic use and both may significantly lower rates of neonatal group B streptococcus sepsis (screening-based more than risk-based for both). The risk-based approach is simpler than the screening-based approach. CONCLUSIONS: Practitioners should select one of the two protocols and use it consistently. The differences in efficacy are small; a practitioner may not see a difference in outcomes over the course of his or her career, although more antibiotics will be administered using the screening-based approach.

Significance of idiopathic midtrimester polyhydramnios.

It is uncertain whether idiopathic midtrimester polyhydramnios is associated with adverse perinatal outcome. Fifty patients with midtrimester polyhydramnios without apparent etiology were compared to 85 control patients. Demographic, obstetric, and neonatal data were recorded and compared using chi-square, Fisher's exact, and Student t tests. Comparisons were also made within the study group between those patients with resolution of the polyhydramnios and those with persistence. Demographic and obstetric data were similar in both groups. Of study patients, 94% had mild polyhydramnios, which resolved in 75.6% of those having follow-up scans. There were no differences in neonatal outcome between study and control groups. Fetal aneuploidy was increased in the persistent polyhydramnios group (2 of 10, 20%) compared to the group with spontaneous resolution (none of 33, 0%), P = 0.049. Mild idiopathic midtrimester polyhydramnios resolves frequently and, if so, is not associated with adverse perinatal outcome. However, persistence of polyhydramnios is associated with an increased risk of fetal aneuploidy, and fetal karyotyping should be considered.

Significance of echogenic foci in the left ventricle of the fetal heart in a low-risk population.

OBJECTIVE: To determine if there exists a significant association between prenatally detected left ventricular echogenic foci and chromosomal abnormalities. METHODS: Over a 10-month period the presence of intracardiac echogenic foci was recorded on all low-risk patients referred for anatomical assessment. The study group consisted of 113 singleton fetuses and was compared to a control group with no foci. RESULTS: Among the study group with echogenic foci, 5 chromosomal abnormalities (three trisomies) were detected. In the control group only one chromosomal abnormality was diagnosed. CONCLUSION: An association exists between the finding of intracardiac echogenic foci in the fetus and the presence of chromosomal abnormalities.