Maternal intrapartum antibiotic treatment continues to exert a bactericidal effect on the umbilical cord and peripheral venous blood of newborn infants

AIM

It is unclear whether maternal intrapartum antibiotic treatment (IAT) continues to exert a bactericidal effect on common pathogens in neonates. We studied the in vitro bactericidal effect of IAT on the cord and peripheral venous blood of newborn infants.

METHODS

Umbilical cord and peripheral venous blood from newborn infants born at Kaplan Medical Center, Israel, from April to October 2014 were studied for serum bactericidal titres against Group B Streptococcus (GBS) and Escherichia coli (E. coli) strains. We studied 60 samples of umbilical cord blood and 18 samples of peripheral venous blood from 60 newborn infants whose mothers received IAT. The controls were 10 samples of cord blood from mothers without IAT.

RESULTS

Cord blood exerted a bactericidal effect against 98% of GBS isolates but only 8% of E.coli isolates. Peripheral blood exerted a bactericidal effect against GBS in 94% of cases, but not against E. coli. No bactericidal effect was seen in the blood from the controls.

CONCLUSION

We found a continued bactericidal effect of umbilical cord blood and neonatal peripheral blood from newborn infants of IAT-treated mothers, mainly against GBS, but rarely against E. Coli. These findings may assist clinicians treating at-risk infants exposed to IAT.

Does assisted reproduction technology, per se, increase the risk of preterm birth?

There is little doubt that all methods of assisted reproduction increase the likelihood of multiple pregnancy and, as a result, increase the likelihood of preterm birth. Data from the East Flanders Prospective Twin Study clearly show that the proportion of spontaneous to iatrogenic twins has changed from 25:1 to 1:1 over the past two decades. Data from the very low birthweight (VLBW) Infant Database of the Israel Neonatal Network showed that 10% of VLBW singletons were a result of assisted reproduction compared with 60% of the VLBW twins and 90% of the VLBW triplets. Irrespective of plurality, an association between preterm birth and assisted reproduction has long been suspected and was related to causes such as iatrogenic preterm birth (in the so-called 'premium' pregnancies), fertility history, past obstetric performance and to underlying medical conditions of the female partner. With more data available, a clearer picture is defined. Two different, recent meta-analyses showed that singleton pregnancies resulting from in vitro fertilisation (IVF) have increased rates of preterm birth at <33 weeks of gestation (OR 2.99; 95% CI 1.54-5.80), at <37 weeks of gestation (OR 1.93; 95% CI 1.36-2.74) and a relative risk of 1.98 (95% CI 1.77-2.22) for preterm birth in singleton pregnancies resulting from in vitro fertilisation embryo transfer/gamete intra fallopian transfer (IVF-ET/GIFT) compared with naturally conceived pregnancies. Since there is no way to predict which pregnant woman is at increased risk of preterm birth, it may be advisable to consider all pregnancies after assisted reproduction as being at risk. In any case, the most appropriate endpoint after assisted reproduction should also include preterm or term birth as measure of success.

Lower embryonic loss rates among twin gestations following assisted reproduction

PURPOSE

To determine whether maternal age and number of transferred embryos influence early pregnancy losses in twin pregnancies compared to singletons following IVF/ICSI.

METHODS

We compared the pregnancy loss rates in singleton (n = 549) and twin (n = 252) gestations, stratified by maternal age (< or = 35 and > 35 years) and the number of transferred embryos (1-3 and 4-9).

RESULTS

Loss rates of singleton pregnancies were significantly higher than that in twins (OR 3.0, 95% CI 1.9, 4.9), especially among singletons conceived after transfer of 4-9 embryos (OR 5.0, 95% CI 2.2, 11.9). Younger mothers of twins had lower loss rates (OR 0.3, 95% CI 0.1, 0.9).

CONCLUSION

Twins have a significantly reduced spontaneous miscarriage rate compared with singletons following IVF/ICSI. Higher implantation rates per cycle (i.e., development of twins rather than one live embryo) may represent a better capacity of the uterus for early embryonic development.

Strangulation of the umbilical cord due to combined amniotic band and true knot

A case of fetal death due to an amniotic band and an umbilical cord true knot is presented. To the best of our knowledge the simultaneous occurrence of true knot of cord and amniotic band has never been previously reported and may shed light on the possible time of true knot formation in this case.

Effect of birth order on neonatal morbidity and mortality among very low birthweight twins: a population based study

OBJECTIVE

To study the effect of birth order on the risk for respiratory distress syndrome (RDS), chronic lung disease (CLD), adverse neurological findings, and death in very low birthweight (VLBW; < 1500 g) twins.

METHODS

A population based study of VLBW infants from the Israel National VLBW Infant Database. The sample included all complete sets of VLBW twin pairs admitted to all 28 neonatal intensive care units between 1995 and 1999. Outcome variables were compared by birth order and stratified by mode of delivery and gestational age, using General Estimating Equation models, with results expressed as odds ratio (OR) with 95% confidence interval (CI).

RESULTS

Second twins were at increased risk for RDS (OR 1.51, 95% CI 1.29 to 1.76), CLD (OR 1.36, 95% CI 1.11 to 1.66), and death (OR 1.24, 95% CI 1.02 to 1.51) but not for adverse neurological findings (OR 1.20, 95% CI 0.91 to 1.60). Mode of delivery did not significantly influence outcome. The odds ratio for RDS in the second twin was inversely related to gestational age, and the increased risk for RDS and CLD was found in both vaginal and caesarean deliveries.

CONCLUSIONS

VLBW second twins are at increased risk for acute and chronic lung disease and neonatal mortality, irrespective of mode of delivery.

The worldwide impact of iatrogenic pregnancy

OBJECTIVES

To outline maternal and perinatal consequences of iatrogenic pregnancies.

METHODS

Review of recently published literature.

RESULTS

The problems of iatrogenic pregnancies derive from major changes in the lifestyle of women during the second half of the 20th century, whereby the age at which childbirth is desired has advanced. At the same time, the naturally reduced fecundity of advanced age, as well as involuntary infertility, were met by new, effective, and costly, treatments. The side-effect of attempts to maximize success rates of such treatments was a remarkable increase in the numbers of multiple gestations, which are invariably associated with serious maternal and perinatal complications.

CONCLUSIONS

The best method to reduce the impact of iatrogenic pregnancies is to re-define our concept of success after infertility therapy-from live birth (of any number of fetuses) to singleton live birth per treatment-and to adopt a conscientious and rational approach to achieve it.

Is the sampling site along the umbilical artery significant?

The purpose of umbilical blood sampling is to obtain accurate reflection of fetal acid-base status at birth. The site along the umbilical artery from which blood should be sampled postpartum was not specified. We evaluated if blood gases and pH values from three sampling sites along the umbilical artery are different. After defining the range of intraobserver (method) variability, blood pO(2), pCO(2), and pH were directly determined. The data showed consistent and significant increases in arterial pH and pCO(2) values and decreases in pO(2) values from near the fetal cord insertion to the placenta. The largest difference was noted between the fetal site and the placental plate and the smallest between the site near the placental cord insertion and the placental plate. We conclude that the site of cord blood sampling should be standardized and the umbilical artery should be sampled at a site nearest to the neonate.

Excess risk of mortality in very low birthweight triplets: a national, population based study

BACKGROUND

Neonatal morbidity and mortality differ between singletons, twins, and triplets.

OBJECTIVE

To evaluate whether plurality is associated with excess risk of neonatal morbidity and poor outcome (death, chronic lung disease, or adverse neurological findings) in very low birthweight (VLBW) infants from a national, population based cohort.

METHODS

The Israel national VLBW infant database has prospectively collected extensive perinatal and neonatal data on all liveborn VLBW infants since 1995. The study sample (n = 5594) consisted of all singletons (n = 3717) and all complete sets of twins (n = 1394) and triplets (n = 483) born during 1995-1999. To account for differences in case-mix, both univariate and multivariate comparisons that included confounding variables such as antenatal steroid treatment and mode of delivery were performed for each of the outcome variables.

RESULTS

There was a small inverse correlation between gestational age (GA) and birth weight (BW) and the number of fetuses (singletons: GA 28.9 (2.6) weeks, BW 1096 (269) g; twins: GA 28.4 (2.3) weeks, BW 1062 (271) g; triplets: GA 28.5 (2.4) weeks, BW 1049 (259) g). Triplets were significantly more likely to have been conceived following fertility treatments, to have received antenatal steroids, and to be delivered by caesarean section. Respiratory distress syndrome was significantly more common in twins and triplets in spite of the increased exposure to antenatal steroids. Multivariate logistic regression analysis using all significant perinatal covariates showed that triplets were at increased risk of death (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.13 to 2.11), but not of adverse neurological outcome (OR 1.29, 95% CI 0.91 to 1.85) or chronic lung disease (OR 0.69, 95% CI 0.46 to 1.02).

CONCLUSION

Despite considerable differences in the incidence of confounding variables between the groups, VLBW triplets are at increased risk of death compared with twins and singletons. In addition, VLBW twins and triplets more often have respiratory distress syndrome but not chronic lung disease or adverse neurological findings.

The risk of fetal loss associated with Warfarin anticoagulation

OBJECTIVES

To examine if fetal risks associated with Warfarin anticoagulation during pregnancy may have been over-estimated at the time the drug was contraindicated during pregnancy.

METHODS

Seven case series with the same therapeutic objective for Warfarin anticoagulation published after 1980 were identified. The frequencies of fetal complications were calculated and compared with those of the 1980 compilation.

RESULTS

The frequencies of embryopathy, stillbirths, and neonatal deaths were similar to the 1980 database, but higher with respect to spontaneous abortions (24.1 vs. 8.6%) and premature deliveries (13.9 vs. 4.6%), and lower regarding live births (73.3 vs. 83.7%).

CONCLUSIONS

Fetal risks associated with Warfarin anticoagulation during pregnancy have not been overestimated. Warfarin should not be given in cases where other anticoagulants do not increase the risk for the expecting mother.

Implications of differences in coiling indices at different segments of the umbilical cord

The purpose of this study was to find out if the coiling density is similar in all segments of term singleton umbilical cords. We compared the coiling index (coils/cm) at three different segments of 159 cords. There was no statistical difference between the coiling indices of the placental and middle segment, but significantly increased coiling was found at the fetal end compared with the placental and middle segments. Coiling indices were not significantly correlated with gestational age, cord length or birth weight. We diagnosed concordant hypo- and hypercoiling when the placental and fetal segments had the same density classification, and discordant hypo- and hypercoiling when these segments had different density classifications. Concordant hypocoiling and hypercoiling were found in 4.4 and 6.3% of the cords examined, respectively (total of 10.7%), concordant normal coiling in 95 (59.7%) and discordant density classifications in 29.6%. We concluded that the coiling index should be established in two distinct segments and that the spatial configuration of the coils, which protects the blood flow in the umbilical cord, might not be measured by coil density only.

Incidence and birth weight characteristics of twins born to mothers aged 40 years or more compared with 35-39 years old mothers: a population study

OBJECTIVE

To compare the incidence of twin births and their birth weight characteristics in mothers aged > or = 40 years with those of mothers aged 35-39 years.

METHODS

We used a population-based cohort of Israeli twins delivered between 1993-98 to compare birth weight characteristics of 510 and 2102 twin pairs delivered to mothers aged > or = 40 years (cases) and 35-39 years (controls), respectively.

RESULTS

The incidence of twin mothers aged 40 years or more increased 50% during the study period, ten times more than mothers aged 35-39. There were significantly more nulliparas (P < .001, OR 1.54, 95% CI 1.2, 1.9) and more para > or = 4 (P < .004, OR 1.38, 95% CI 1.1, 1.7) among older mothers. Irrespective of parity, there were no significant differences between mean twin birth weight, total twin birth weight < 3000 g, 3000-4999 g, and > or = 5000 g, and frequencies of very low birth weight neonates.

CONCLUSIONS

Twin birth at the age of > or = 40 years is significantly more likely among either nulliparas or para > or = 4. Birth weight characteristics of twins delivered to mothers aged > or = 40 years are not different from those delivered to 35-39 years old mothers.

Controversial issues in the management of multiple pregnancies

The management of multiple pregnancies represents a true challenge for all sub-specialties concerned with perinatal medicine. Many issues were neglected over the years merely because they were rare and therefore considered not sufficiently important to merit clinical trials. This paper discusses a personal selection of controversial issues, such as multifetal pregnancy reduction of triplets and twins, special cases in multifetal pregnancy reduction, need for invasive genetic studies, management of twin-twin transfusion, discordant fetal conditions, the definition of "term" in multiples, and the controversy about the mode of delivery.

Cesarean section for all twins?

Twin gestations frequently involve maternal and fetal complications, and are quite often considered as "premium" pregnancies. Hence, many clinicians that follow the cliche "no high risk pregnancy should end with a high risk delivery" may deliver twins by CS for many subtle reasons, other than clear-cut, evidence-based, indications. Thus, the decision for a CS in twins, intentionally or not, is based on qualitative variables that were not quantified and on quantitative variables that suggest no advantage for CS in the majority of cases.

Maternal age and birth weight characteristics of twins born to nulliparous mothers: a population study

In order to examine birth weight characteristics of twins delivered to nulliparous mothers in relation to maternal age, we used a population-based cohort of Israeli twins delivered between 1993-98 to select all 4793 (37.6%) nulliparas who delivered twins. Maternal age was subdivided as less than 20 years, 20-24, 25-29, 30-34, 35-39, and 40 years or more. We counted the frequencies of each total twin birth weight (twin A + twin B) in each of three categories (less than 3000, 3000-4999, and more than 5000 g) and the frequency of very low birth weight (VLBW, less than 1500 g) neonates in each of the six maternal age categories. There were significantly more nulliparas in the twin population at age groups less 30 years and significantly less at ages 30 years or more. We found a highly significant inverse correlation between the proportion of nulliparas and maternal age group, decreasing from 71.8% at less than 20 years to 18.6% at age 35-39 years (% nulliparas = 85 - 13.7 x age group, Pearson R2 = 0.98). However, this trend changed abruptly to the observed figure of 25.9% nulliparas aged 40 years or more instead of the expected 2.8%. We failed to reveal any significant difference in birth weight characteristics between the maternal age groups (all p > 0.05, all confidence intervals included 1.0). The more than tenfold deviation of the observed from the predicted frequency of nulliparas aged 40 years or more suggests that a different relationship between parity and age occurs at this age group. Maternal age of nulliparas is not associated with different birth weight characteristics of their twins.

Adaptive growth restriction as a pattern of birth weight discordance in twin gestations

OBJECTIVE

To challenge the hypothesis that discordant growth is a normal variation by relating birth weight discordance to total twin birth weight. METHODS Among 12,565 Israeli live-born twin pairs (1993-98), we compared total twin birth weight decile, the frequencies of three levels of discordance in the general population, over 25% discordance between like- versus unlike-sex pairs, and over 25% discordance between pairs delivered by primiparas versus multiparas.

RESULTS

We found a marked change in the best-fit correlation function with increased discordance: level 15-24.9% was inversely linear whereas levels 25-34.9% and over 34.9% were inversely logarithmic (R(2) =.47,.88, and.9, respectively). The best-fit correlation of frequencies of more than 25% discordance was inversely logarithmic and similar in like- and unlike-sexed twins across deciles functions (P =.7, odds ratio [OR] 1.0, 95% confidence interval [CI] 0.9, 1.2). The overall frequencies of discordance were also similar (9.3% versus 10.2%, P =.11, OR 0.9, 95% CI 0.8, 1.0). The frequencies of primiparas decreased linearly (R(2) =.98) and the frequencies of more than 25% discordant pairs in multiparas and primiparas across the deciles had similar inversely logarithmic patterns (P =.55, OR 1.0, 95% CI 0.9, 1.2). Discordance over 25% was significantly more frequent among primiparas (P <.001, OR 1.45, 95% CI 1.3, 1.6).

CONCLUSION

The observed patterns of birth weight discordance did not substantiate normal variation but an adaptive growth restriction that might explain why the likelihood of discordant growth decreases as total twin birth weight increases.

The conjoined twins of Löwen

This paper discusses an unusual etching of unlike-sex conjoined twins of the syncephalus type dated 1547. The authenticity of the case is discussed in terms of the biological plausibility of such twins and in the light of mediaeval understanding of the twinning process. Unlike-sex syncephalic twins may occur as a result of dispermic fertilisation, or be an erroneous depiction of an asymmetrical anomaly of the external genitalia of a like-sex pair, mimicking the genitals of the other sex. On the other hand, the Löwen etching conforms with mediaeval beliefs that conjoined twins are divine punishment and therefore were used for ecclesiastical and perhaps commercial purposes. The historical context of the drawing, in which the relation between religion, media, and medicine satisfied the eagerness of the public for curios of Nature, is no longer valid. Thus the Löwen etching opens a window to the past from which modern medicine can be appreciated.

Conditions predisposing to maternal mortality in twins and singletons, US birth cohort 1989

Twin pregnancy is one of the most important conditions associated with increased perinatal mortality and morbidity. The consequences of twin pregnancy on the mother have not been explored in great detail. The aim of this study was to analyze the population-based data from the United States and delineate the various conditions of twin pregnancies which predispose to maternal mortality. Results of this study show that multiple pregnancy is strongly associated with maternal mortality and requires further analysis in order to prepare appropriate therapeutic and prophylactic protocols.

Antepartum risks of shoulder dystocia and brachial plexus injury for infants weighing 4,200 g or more

A cohort of 236 vaginally delivered neonates weighing > or = 4,200 g was evaluated. Shoulder dystocia was encountered in 27 deliveries (11.4%) and brachial plexus injury was diagnosed in 3 infants (1.3%). The 'traditional' antepartum risk factors could not be associated with shoulder dystocia. In this cohort, primiparity was significantly more frequent among the dystocia cases (OR = 8.58, 99% CI = 1.35-54.35, p = 0.021). Shoulder dystocia could not be attributed to a particular difference between the current and the previous heaviest birth weight. A policy of cesarean section for all infants weighing > or = 4,200 g would result in at least 5- to 6-fold increase in cesarean rate in this group of patients. Our data reconfirm that shoulder dystocia and brachial plexus injury are unpredictable, even in macrosomic infants. It is a matter of policy whether to accept the expected 1:9 and 1:79 respective risks associated with vaginal births.

Reseal of ruptured membranes after genetic amniocentesis. A case report

BACKGROUND

One of the most significant complications following genetic amniocentesis is rupture of membranes, reported to occur in 1.15-1.7% of cases. Management of such cases is controversial.

CASE

Genetic amniocentesis complicated by ruptured membranes was diagnosed in a 36-year-old woman. The membranes resealed after 48 hours, and the patient had a favorable outcome.

CONCLUSION

In the case of genetic amniocentesis complicated by ruptured membranes, if chorioamnionitis does not develop, reseal can be expected to occur within seven days in the majority of cases. Thus, conservative management should be the first option.

Risk for one or two very low birth weight twins: a population study

OBJECTIVE

To calculate the frequencies of very low birth weight (VLBW) neonates among twins in a large population database.

METHODS

The database comprised 12,567 live-born twin pairs delivered from 1993 to 1998 in Israel. Low birth weight (LBW) and VLBW were defined as less than 2500 and 1500 g, respectively. We counted the number of pairs with VLBW neonates in three combinations: VLBW-VLBW, VLBW-LBW, and VLBW-over 2500 g. We compared the subsets of nulliparas and multiparas and the frequency of like- versus unlike-sex twins.

RESULTS

The frequency of at least one VLBW twin was significantly higher among nulliparas than multiparas (odds ratio [OR] 2.3; 95% confidence interval [CI] 2.1, 2.6; P <.001). For pairs with VLBW-VLBW and VLBW-LBW combinations, a significantly higher frequency was found among nulliparas than multiparas (OR 2.0; 95% CI 1.7, 2.8; P <.001 and OR 2.6; 95% CI 2.2, 3.1; P <.001, respectively). The risk seemed to be accentuated in like-sex twins. Overall, the risk of having at least one VLBW infant was 1:5 among nulliparas and 1:12 among multiparas. The risk of having two VLBW twins among nulliparas (1:11) was double that of multiparas (1:22).

CONCLUSION

Nulliparas are at significantly increased risk of delivering one or two VLBW twins.

Delivery of breech first twins: a multicenter retrospective study

OBJECTIVE

To assess the risk of vaginal birth of breech first twins by Apgar scores and mortality.

METHODS

We did a retrospective case-control analysis of data from 13 centers that allow vaginal birth for breech first twins. We used depressed 5-minute Apgar scores and neonatal mortality as main outcome measures between vaginal (n = 239) and cesarean (n = 374) deliveries of pairs with breech first twins, stratified by parity, birth weights of first twins, and types of cesarean. The 95% power of our sample size (alpha = .05) was sensitive enough to detect differences of 5% of the overall sample and 25-30% of subgroups.

RESULTS

Vaginal birth was attempted in 61% of 613 pairs. There were significantly more depressed Apgar scores (P = .008, odds ratio [OR] 2.4, 95% confidence interval [CI] 1.2, 4.7) and neonatal deaths (P < .001, OR 9.5, 95% CI 4.0, 23.4) among vaginal births of pairs in whom first twins weighed less than 1500 g but not among the higher-birth-weight cohort (for depressed Apgar scores: P = .76, OR 1.1, 95% CI 0.6, 2.1). Multiparity and elective cesarean seemed to have little influence on outcome measures. Neonatal mortality was associated with extremely preterm twins.

CONCLUSION

There was no evidence that vaginal birth is unsafe, in terms of depressed Apgar scores and neonatal mortality, for breech first twins that weighed at least 1500 g.

Case series of labor induction in twin gestations with an Intrauterine Balloon catheter

The efficacy and safety of labor induction using an intrauterine balloon catheter in twin pregnancies has been evaluated. During the study period (1992-1997), labor was induced at 36-42 weeks in 17 twin gestations. Labor induction was indicated for preeclampsia (n = 10), birth weight discordance (n = 3), suspected fetal distress (n = 2) and postdates (n = 2). Twin A was in vertex presentation in all cases. An intrauterine balloon catheter was inserted transcervically followed by augmentation whenever required. Vaginal delivery was achieved in 15 (88.2%) patients. The mean interval from balloon insertion to delivery was 17.05 h, with 80% deliveries occurring within 24 h of catheter insertion and 80% occurring within 12 h of catheter expulsion. Birth weight was 2,514+/-244 and 2,421+/-367 g for twin A and B, respectively. Oxytocin was required in 4 patients. Postpartum hemorrhage was noted in 1 patient. One patient with no progress of labor and 1 with suspected intrapartum fetal distress required cesarean section. All neonates had a 5-min Apgar score of 10. The data suggest that an intrauterine balloon catheter appears to be safe and effective to induce labor in twin gestations.

The relation between inter-twin birth weight discordance and total twin birth weight

OBJECTIVE

We tested the hypothesis that the frequency of growth discordance among twins is not related to the uterine capacity for carrying twins.

METHOD

We counted and compared the frequencies of birth weight discordance of more than 25% in an unlike-sexed twin cohort (n = 1244) and in a population-based twin cohort (n = 7570) across the deciles of the total twin birth weight (twin A + twin B) distribution. The birth order of the heavier twin was noted.

RESULTS

Similar frequencies of discordant pairs were found in both cohorts (11% and 12%, respectively; Mantel-Haenszel chi2 test: P = .131, odds ratio (OR) 0.9, 99% confidence interval (CI) 0.67, 1.11; Woolf test for heterogeneity: two-tailed P = .472). In the discordant pairs, twin A was considerably more often the heavier twin in all birth weight deciles (unlike-sexed cohort: P < 10(-8), OR 5.9, 99% CI 3.0, 11.7; population-based cohort: P < 10(-8), OR 3.1, 99% CI 2.3, 4.0), and in both cohorts (inter-cohort difference: P = .109, OR 1.4, 99% CI 0.83, 2.32). Both cohorts showed a similar nonlinear trend: given that X = decile order, discordance decreased as a function of 22.0 - 6.54 ln[X] for the unlike-sexed twins cohort and 23.0 - 8.18 ln[X] for the population-based cohort, with r values of 0.967.

CONCLUSION

The more favorable the uterine milieu for carrying twins, the smaller the likelihood of discordant twin growth. Birth order of the heavier twin appears to be an integral part of the discordance phenomenon. The similarity of the cohorts suggests that these conclusions are valid for both like and unlike-sexed twins.

Computed sonography: requiem to echogenicity assessment?

We studied the influence of changes in gain settings, log compression, persistence, preprocessing, and postprocessing on image density in the fetal liver model. Each parameter was studied while the others were held constant. The image density was objectively measured by electrooptical transmission densitometry using a transparent film output. Neither the persistence nor the preprocessing levels significantly changed image density. Postprocessing of sonographic images produced significant differences (p < 0.02) in mean image density of most of the various postprocessing curves and is a serious confounder of tissue echogenicity assessment. The data reconfirmed that there is a linear relationship (r = -0.94 to -0.997) between image density and gain setting. However, each log compression setting significantly changed (p < 0.0000001) this relationship, obviating possible image density calibration. Our data suggest that manipulation of image parameters by computed sonographic technology obviates accurate echogenicity assessment.

Maternal mortality in twin gestations

OBJECTIVE

To review various aspects of maternal morbidity and delivery complications leading to maternal death in twin gestations.

STUDY DESIGN

Literature research.

RESULTS

The incidence of maternal mortality associated with twin gestation is not known but can be estimated from a few community-based series and from studies on maternal morbidity related to twins. The combination of physiologic changes and perinatal pathologies that are either unique or more common in twin gestations (e.g., preeclampsia/eclampsia, need for tocolysis, anemia, abruption placentae, special delivery circumstances and cesarean section) is certainly increasing the maternal risk for serious morbidity and even mortality.

CONCLUSION

Twin pregnancies should be included among the categories of pregnancy-related maternal death in order to learn how to eliminate avoidable mortality in twin gestations.

Quantitative assessment of gray-level perception: observers' accuracy is dependent on density differences

Sonographic image density represents tissue echogenicity, or the acoustic nature of scanned tissue. It has the potential to distinguish normal from abnormal tissue. Humans are poor assessors of tissue echogenicity, yet their abilities have not been quantitatively compared to more objective methods. We compared the accuracy of image density differentiation by the human eye and by densitometry in the fetal liver model. A group of 60 observers was asked to compare the echogenicity of three pairs of images of a fetal liver. Twenty-three repeated the comparison several weeks later. Image density was measured by electro-optical densitometry. The two-tailed signed rank test was used to compare the observer's perceptions with the density values and the repeated observations with the original responses. The density of each fetal liver image in pair A was the same. Image B1 had a 12.3% lower density than image B2, and image C1 had a 6.3% greater density than image C2. Observers were accurate more often when comparing images with large density differences (pair B) than they were when comparing images with the same density (pair A) or with small density differences (pair C). Accuracy was not related to being medically qualified or from an obstetric or gynecological department. Intraobserver variation was not significant. We conclude that the human eye is extremely inaccurate at discerning differences in echogenicity when images have small or no differences in optical density. Densitometry is, therefore, indispensable for accurate image density assessment.

Post-traumatic vulvar endometriosis

We report a case of vulvar endometriosis presenting as a vulvar mass following trauma in a 12 years old, 3 months post-menarcheal girl. The presumptive etiology is the direct implantation of endometrial cells. Painful swelling of the vulvar mass appeared gradually during menses. Excision of suspected vulvar endometriosis is suggested as the definite treatment.

Is intertwin birth weight discordance predictable?

OBJECTIVE

To compare the efficacies of intertwin difference in abdominal circumferences (ACs) and estimated fetal weight (EFWs) to predict birth weight discordance in twin gestations.

METHODS

Ninety pairs of twins with sonographic measurements of AC and femur length, performed within 2 weeks before delivery, were included in the study. The EFW was calculated (Hadlock's formula). We used Bayes' theorem and the Mantel-Haenszel chi 2 test to calculate and compare the rates of false-positive and false-negative prediction of the cutoff values of 15, 20, and 25% intertwin birth weight discordance by the intertwin EFW difference and an intertwin AC difference of > or = 18 mm.

RESULTS

There were no significant difference between the two methods to predict birth weight discordance at 15-25% discordance (p = 0.254, OR = 0.33, 95% CI = 1.45-0.24) and at > 25% discordance (p = 0.112, OR 0.18, 95% CI = 0.03-1.34).

CONCLUSIONS

Both the intertwin AC difference (> or = 18 mm) and intertwin EFW difference have similar negative predictive values and the same efficacy to exclude discordant growth. Because of the relatively low positive predictive values, birth weight discordance cannot be accurately predicted by either method.

Menopause is associated with a significant increase in blood monocyte number and a relative decrease in the expression of estrogen receptors in human peripheral monocytes

PROBLEM

The clinical significance of the differential expression of estrogen receptor (ER) in human monocytes was evaluated.

METHOD

Two color flow cytometry analysis was used on peripheral blood samples of young and postmenopausal females and postmenopausal females treated with estrogen replacement therapy. In addition, the monocyte and lymphocyte counts and the blood estrogen levels of each patient were determine.

RESULTS

During menopause there is a significant decrease in the percentage of ER positive monocytes, and an increase in blood monocyte number, which declines following estrogen replacement therapy to values of the young.

CONCLUSIONS

These findings suggest that estrogen modulates the monocyte numbers and its effects may be mediated through the ER in the monocytes.

The intrauterine ponderal index in relation to birth weight discordance in twin gestations

OBJECTIVE

To establish the relationship between the fetal ponderal index and birth weight discordance in twins.

METHOD

The fetal ponderal index (estimated fetal weight divided by femur length3) was calculated in 86 pairs of twins delivered within 2 weeks of the last sonography and analyzed in relation to birth weight discordance.

RESULTS

A weak but significant correlation between fetal ponderal index and birth weight (r = 0.26, P < 0.0007) but no correlation with gestational age (r = 0.035, P = 0.65) were found. Members of concordant pairs (< 15% birth weight difference) had a significantly higher fetal ponderal index compared with members of mildly (15-25%) discordant pairs (P < 0.02), but not as compared with members of severely discordant (> 25%) pairs.

CONCLUSION

The characteristics of the fetal ponderal index in twins are similar to those in singletons. Fetal size seems to be diminished in severe but not in mild discordants. However, in its present form, the fetal ponderal index is a poor predictor of discordant growth and therefore should be employed cautiously in twin gestations.

Echogenicity of fibroadenoma and carcinoma of the breast. Quantitative comparison using gain-assisted densitometric evaluation of sonograms

The purpose of this study was to evaluate the role of ultrasonography in differentiation between the echogenic characteristics of carcinoma and those of fibroadenoma of the breast. Two mathematical transformations of the measured density on a sonographic image of the breast lesion at three different system gain settings were used in cases of carcinoma (n = 16) and fibroadenoma (n = 31) to provide standardized density values. A significant correlation was found between the tumor and the surrounding tissue densities in both carcinomas (r = 0.77, P = 0.0004) and fibroadenomas (r = 0.79, P < 0.000001. The mean standardized density of the tumor was significantly higher (P < 0.0001) than the surrounding tissue in both carcinomas (2.03 +/- 0.64 D versus 1.23 +/- 0.38 D) and fibroadenomas (2.09 +/- 0.48 D versus 1.33 +/- 0.3 D). However, the differences between density values of carcinoma and fibroadenomas were not significantly different. The data suggest that it may not be possible to differentiate breast carcinoma and fibroadenomas on the basis of the echogenicity of solid breast masses.

Quantitative comparison of two distinct echogenic structures appearing on the same image using gain-assisted densitometric evaluation of sonograms (GADES)

Gain-assisted densitometric evaluation of sonograms with two distinct echogenic structures appearing on each image was performed to establish if their density-gain setting curves have similar inclinations. We used the breast model (n = 67) in which hyperechoic masses were compared to the surrounding hyperechoic tissue at the optimal gain (Gopt) and at Gopt + 5. Both structures had significantly different film-corrected densities and showed a linear decline of density as the system gain increased from Gopt - 5 to Gopt + 5. The least squares regression lines were almost parallel. The density-gain unit decrease from Gopt - 5 to Gopt was not different, but the decrease from Gopt to Gopt + 5 reached statistical significance. The data suggest that skewed values are theoretically possible in comparing two distinct echogenic structures. However, within the gain intervals used in GADES, these differences are negligible and comparisons are as accurate as with the assessment of a single echogenic structure.

Pregnancy order. A factor influencing birth weight in twin gestations

To test the hypothesis that increased twin birth weight is expected with increased parity, we conducted a retrospective, cross-sectional evaluation of 430 twins, focusing on birth weight and growth discordance parameters in five parity groups (para 1-4 and > or = 5). The mean birth weight of twin A, B and both twins was significantly lower in primiparous patients as compared to para 2-4 but not as compared to para > or = 5 patients. The frequency of twins weighing < 1,500 g was similar in all groups, but a significantly higher frequency of twins weighing 1,500-2,500 g and lower frequency at > 2,500-g twins were found in the para 1 group as compared to the groups with higher parities. Presentation combinations were not different in the five parity groups, nor were the frequencies of growth discordance categories. However, discordants among pairs, with each infant weighing < 2,500 g, occurred almost twice as often in para > or = 5 as compared to the other parity groups. Our data indicate that primiparae seem to have significantly smaller twins as compared to multiparae. This trend was independent of the presentation combinations and growth discordance pattern and seems to result from a higher frequency of twins weighing 1,500-2,500 g in primiparae.