Biomedical subjects
I Blickstein
Publications and source records attributed to I Blickstein.
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.
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.
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.
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.
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.
Estimating the risk of cerebral palsy after assisted conceptions.
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[Cerebral palsy and multiple pregnancy].
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Zygotic splitting after assisted reproduction.
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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.
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.
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.
Postpartum determination of umbilical artery blood gases: effect of time and temperature.
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'Reflections on the hypothesis for the etiology of spastic cerebral palsy caused by the "vanishing twin" syndrome'.
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[Monozygotic twins: reproductive anomaly or successful natural cloning?].
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[History of monozygotic twin research].
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