Biomedical subjects

Isaac Blickstein

Publications and source records attributed to Isaac Blickstein.

At least 19 recordsLinked to original sources

PubMed2006

The effect of ICSI, maternal age, and embryonic stage on early clinical loss rate of twin versus singleton pregnancies.

OBJECTIVES: To compare early loss rates between twin and singleton pregnancies following ART. STUDY DESIGN: First-trimester sonography counted the number of embryos with positive heartbeat in women undergoing IVF/ICSI and transfer of one to three embryos. The number of lost pregnancies was calculated from a second-trimester sonogram. Loss rates of the entire pregnancy were related to maternal age <38 or > or = 38 years, IVF or ICSI, and cleavage or blastocyst stage embryo transfers (in ICSI cases). RESULTS: Patients underwent IVF with (n = 672) and without (n = 189) ICSI. The overall odds of miscarrying the entire singleton pregnancy were 2.6 times that of a twin gestation (95% CI 1.5, 4.5). The disadvantage for singletons compared to twins seems more apparent in pregnancy after ICSI in the subgroup of patients <38 years (OR 2.9, 95% CI 1.5, 5.8). In this subgroup, the disadvantage conferred to singletons appeared only among days 2-3 embryo transfers (OR 3.0, 95% CI 1.3, 7.2). CONCLUSION: A significantly lower early spontaneous loss rate of twin pregnancies seems related to ICSI followed by cleavage stage embryo transfer in patients <38 years.

Adult↗

PubMed2006

Effect of the mode of assisted reproductive technology conception on obstetric outcomes for survivors of the vanishing twin syndrome.

Survivors of the "vanishing" twin syndrome, which occurred in dichorionic twins only, and singletons that began as singletons, had similar mean gestational duration and birth weights, as well as similar frequencies of maternal and neonatal complications. This similarity persisted when conventional IVF and IVF plus ICSI cases were separately evaluated.

Abortion, Spontaneous↗

PubMed2006

Prospective risk of intrauterine death of monochorionic-diamniotic twins.

OBJECTIVE: The purpose of this study was to calculate the prospective risk of fetal death in monochorionic-diamniotic twins. STUDY DESIGN: We evaluated 193 monochorionic diamniotic twin pregnancies that were followed and delivered after 24 weeks. Surveillance included cardiotocography and sonography performed at least once weekly. The prospective risk of fetal death was calculated as the total number of deaths at the beginning of the gestational period divided by the number of continuing pregnancies at or beyond that period. RESULTS: The fetal death rate was 5 of 193 pregnancies (2.6%; 95% CI, 1.1, 5.9); the prospective risk of stillbirth per pregnancy after 32 weeks of gestation was 1.2% (95% CI, 0.3% - 4.2%). CONCLUSION: Under intensive surveillance, the prospective risk of fetal death in monochorionic-diamniotic pregnancies after 32 weeks of gestation is much lower than reported and does not support a policy of elective preterm delivery.

Adult↗

PubMed2006

Plurality-dependent risk of severe intraventricular hemorrhage among very low birth weight infants and antepartum corticosteroid treatment.

OBJECTIVE: This study was undertaken to compare the effect of antenatal corticosteroid therapy on the risk for severe intraventricular hemorrhage (IVH grade III-IV) in preterm singleton and multiple very low birth weight (VLBW) infants. STUDY DESIGN: The occurrence of severe IVH was recorded in 5022 singleton, 2032 twin, and 582 triplet infants, delivered at 24 to 32 weeks' gestation, registered in the Israeli National VLBW infant database. Antenatal corticosteroid therapy was defined as complete, partial, or none. RESULTS: The incidence of IVH grade III-IV ranged from 6.8% among singletons receiving complete course to 29.3% in triplets without antenatal corticosteroid treatment. Complete treatment significantly reduced the incidence of IVH in all plurality groups. The adjusted risk for IVH among multiple infants who received a complete course compared with singletons was not significantly different, odds ratio (OR) 1.3, 95% CI 1.0-1.7 for twins and OR 1.5, 95% CI 0.9-2.3 for triplets. CONCLUSION: Complete course of antenatal corticosteroid therapy was independently associated with decreased risk for severe IVH in singleton and in multiple preterm VLBW infants.

Betamethasone↗

PubMed2006

Diagnosis and management of heterokaryotypic monochorionic twins.

The diagnosis, management, and outcome of six consecutive heterokaryotypic monochorionic twins were evaluated. All suspected cases, based on discordant ultrasound findings, underwent amniocentesis of both sacs. Two cases also had chorionic villous sampling (CVS). Dual amniocentesis was superior to CVS in diagnosing heterokaryotypic monochorionic twins. In four cases, the X-chromosome was involved and autosomal aneuploidy was noted in the others. In five cases, the anomalous twin was selectively reduced by cord coagulation. All pregnancies ended with a phenotypically normal liveborn and all children are developing normally at 1-7 years of age.

Adult↗

PubMed2006

Outcome of 518 salvage oocyte-cryopreservation cycles performed as a routine procedure in an in vitro fertilization program.

OBJECTIVE: To document outcomes of oocyte cryopreservation performed as a routine procedure in an IVF program. DESIGN: Describing the rate of oocyte survival, embryo transfer (ET), implantation, and live births of IVF-intracytoplasmic sperm injection performed on thawed oocytes. SETTING: Reproductive medicine center in Italy. PATIENT(S): Women (n = 696) who failed to conceive after IVF-intracytoplasmic sperm injection with fresh oocytes. INTERVENTION(S): Surplus oocytes obtained during a failed cycle with fresh oocytes were frozen and then were thawed, micromanipulated, and transferred in a later cycle. MAIN OUTCOME MEASURE(S): Rates of oocyte survival, ETs, implantation, and live births were calculated in the entire cohort and in patients aged 38 years. RESULT(S): There were 29 pregnancies, for a total implantation rate of 6.3% (95% CI: 4.3, 9.0) per 456 ET cycles. The clinical-pregnancy rate was 19 (4.2%; 95% CI: 2.6, 6.4) of 456 ET cycles, with a take-home-baby rate of 7 (1.5%; 95% CI: 0.7, 3.0) of 456 ET cycles. CONCLUSION(S): Cryopreservation performed as a routine procedure for so-called salvaging of surplus oocytes is associated with poor implantation rates and with a probability of 1 live birth in 65 ET cycles.

Adult↗

PubMed2006

Thrombophilia and women's health: An overview.

Thrombophilia, whether inherited or acquired, is one of the hot topics in women's health. Several factors, some of which are specific to the female patient, enhance thrombus formation in the presence of thrombophilia and include oral contraception, hormone replacement therapy, pregnancy, and puerperium. Thrombotic events are not only restricted to venous thromboembolism but also are believed to cause repeated embryonic loss, fetal loss, placental abruption, intrauterine growth restriction, and severe pre-eclampsia. It seems that some thrombophilias, and a combination of thrombophilic factors, carry a greater risk than others for a given adverse outcome. The addition of LMWH to the armamentarium was associated with conceptual change in the practice of anticoagulation. Care should be exercised in the interpretation of various risks and the potential of anticoagulation as a remedy to reduce that risk.

Arteries↗

PubMed2006

The association between small-for-gestational age triplet pregnancies and neonatal mortality: a novel approach to growth assessment in multiple gestations.

It is customary to estimate the uteroplacental function in singletons by defining appropriateness of birth weight by gestational age. Such a measure, however, is not available for the entire multiple pregnancy set. We evaluate a new index, total triplet birth weight, expressed as multiples of the median (MOM) birth weight of singleton gestations. We categorized triplet sets as small-, appropriate-, and large-for-gestational age pregnancies (SGA, AGA, and LGA, respectively), defined as <1 SD, +/-1 SD, and >1 SD from the mean MOM birth weight of singleton gestations. We used the 1995-1998 US matched multiple dataset to evaluate this index and to explore the association between the three categories in terms of risk of neonatal mortality. The mean +/- SD MOM value was 2.3 +/- 0.4. There was an inverse correlation between mean MOM and gestational age. LGA pregnancy status was associated with multiparity, race (being white), and high social status (education). Maternal age did not influence MOM scores. Compared with the LGA pregnancy category, the risk for neonatal mortality was more than doubled in the AGA pregnancy group and more than 9-fold in the SGA pregnancy category. We propose that this new measure could be a useful proxy for the uteroplacental efficiency in a similar way that the SGA designation works for singleton infants.

Adult↗

PubMed2006

Induction of labor with oral misoprostol in nulliparous mothers of twins.

The efficacy and safety of oral misoprostol for labor induction of twins is unknown. We conducted a retrospective case-control study to evaluate the use of oral misoprostol in near term (> or =35 weeks) twin pregnancies in nulliparas. Eligible cases were given 100 mcg oral misoprostol, which was repeated after 6 h if labor did not start. Either a third dose or diluted oxytocin infusion were given in intractable cases. Diluted oxytocin infusion was used for augmentation. Controls were nulliparas delivered at > or =35 weeks by elective cesarean section. The two groups were comparable in most aspects, except for fetal malpresentation, which was the major reason for avoiding induction. Of the 69 patients in whom labor was induced, 53 (76.8%) had a vaginal birth, 3 (4.3%) had a combined twin delivery, and 13 (18.8%) had a cesarean during labor. The mean length of stay of the neonates was significantly shorter among study cases, without significant difference in the frequency of delayed discharges as an overall proxy for neonatal complications. Labor induction with oral misoprostol could be offered to patients in whom near term vaginal twin delivery is unequivocally permitted and wish to deliver by the vaginal route.

Administration, Oral↗

PubMed2006

The Northwestern twin chorionicity study: testing the 'placental crowding' hypothesis.

OBJECTIVE: To evaluate the relation between placental proximity and frequency of birth weight discordance and small-for-gestational age (SGA) infants. STUDY DESIGN: Retrospective three-tier chorionicity analysis of 1155 twin placentas comparing birth weight characteristics of the twins in different placental types. RESULTS: Dichorionic-separate, but not dichorionic-fused twins, are heavier than monochorionic-diamniotic and monoamniotic twins (2376+/-721 vs. 2274+/-770, P < 0.006, and 2376+/-721 vs. 2166+/-782, P < 0.04). SGA twins are less frequent among dichorionic twins (OR 0.4; 95% CI 0.3, 0.6). Fewer sets with two SGA infants are present among dichorionic-separate compared to monochorionic-diamniotic pairs (OR 0.3; 95% CI 0.1, 0.8). The same trends are found when comparing all dichorionic to all monochorionic twins. Twins of all placental types have similar gestational ages and discordance values. CONCLUSIONS: Dichorionic-separate placentas are least likely to experience 'placental crowding' and thus are associated with heavier twins and fewer sets with one or two SGA infants.

Adult↗

PubMed2006

Timing of cord clamping revisited.

Although cord cutting has been performed since the beginning of mankind, the timing and advantages of early versus delayed cord clamping are still controversial. Early cord clamping (within the first 30 s after birth) is usually justified for potential prevention of postpartum hemorrhage and for immediate treatment of the newborn, but at the same time, may increase Rh-sensitization. Delayed cord clamping is performed after a period of 30 s during which 'placental transfusion' of approximately 80 mL of blood occurs. This amount seems to protect the baby from childhood anemia without increasing hypervolemia-related risks. In preterm infants, delayed clamping appears to reduce the risk of intraventricular hemorrhage and the need for neonatal transfusion. Obtaining cord blood for future autologous transplantation of stem cells needs early clamping and seems to conflict with the infant's best interest. Although a tailored approach is required in the case of cord clamping, the balance of available data suggests that delayed cord clamping should be the method of choice.

Anemia, Iron-Deficiency↗

PubMed2006

Early weight gain does not decrease the incidence of low birth weight and small for gestational age triplets in mothers with normal pre-gestational body mass index.

OBJECTIVE: To examine if the recommended weight gain of >680 g/week during the first 24 weeks of pregnancy decreases the frequency of adverse birth weight outcomes in triplet mothers with a normal pregravid BMI. STUDY DESIGN: Retrospective observational study of a large sample of triplet mothers with a normal (19.8-26) pregravid BMI. Adequate, average, and inadequate weight gains were defined as >680, 500-680, and <500 g/week. Outcome measures were the incidence of >or=1 SGA infant and total triplet birth weight <4500 g. RESULTS: Of the 1166 triplet mothers, 208 (17.8%) gained >680 g/week during their pregnancy. This presumed adequate weight gain did not reduce the incidence of SGA triplets or that of total birth weight <4500 g, irrespective of parity. These adverse birth weight outcomes were 2 to 3.5 times lower among multiparous compared to nulliparous mothers. CONCLUSION: Early weight gain of >680 g/week in triplet mothers with a normal pre-pregnancy BMI is not associated with a decrease in the incidence of adverse outcomes. Weight gain recommendations in triplet pregnancies should be realistic and associated with a low risk-benefit ratio.

Body Mass Index↗

PubMed2005

Plurality-dependent risk of respiratory distress syndrome among very-low-birth-weight infants and antepartum corticosteroid treatment.

OBJECTIVE: The purpose of this study was to determine the effect of antenatal corticosteroids on the incidence of respiratory distress syndrome in singleton infants and multiple infants who weigh <1500 g and are delivered at 24 to 32 weeks of gestation. STUDY DESIGN: The incidence of respiratory distress syndrome was established in 4754 singleton infants, 2460 twin infants, and 906 triplet infants. RESULTS: The incidence of respiratory distress syndrome ranged from 58.2% among singleton infants who received a complete course of antenatal corticosteroid to 81.5% in triplets without any treatment. Complete treatment significantly reduced the incidence of respiratory distress syndrome, compared with partial or no treatment (odds ratio, 0.2-0.6). The adjusted risk for respiratory distress syndrome among infants who received a complete course of antenatal corticosteroids compared with singleton infants increased with plurality (odds ratio, 1.4 and 1.8 for twins and triplets, respectively). CONCLUSION: The effect of corticosteroids decreased with increasing plurality. Irrespective of plurality, a complete course of antenatal corticosteroids significantly reduced the incidence of respiratory distress syndrome, whereas partial treatment had the same effect as no treatment.

Adrenal Cortex Hormones↗

PubMed2005

Estimation of iatrogenic monozygotic twinning rate following assisted reproduction: Pitfalls and caveats.

The true incidence of monozygosity after assisted reproduction is unknown. Proxy estimations, such as counting the number of monochorionic twins, using Weinberg's differential rule, and counting cases where the number of fetuses exceeds the number of transferred embryos, are less accurate than zygosity assessment in all twins. These methods commonly underestimate the true frequency of zygotic splitting because they disregard like-sexed monozygotic-dichorionic twins, consider twin births rather than twin pregnancies, and do not count the number of higher-order multiples with a monozygotic pair. Because zygotic splitting following assisted reproduction is of biological interest as well as of clinical significance, efforts should be directed to increase the accuracy of zygosity determination. This will improve understanding of the zygotic splitting phenomenon and its relation to pathologic processes.

Embryo Transfer↗

PubMed2005

The decreased rates of triplet births: temporal trends and biologic speculations.

Recent data from the US and from England and Wales demonstrate decreasing rates of higher-order multiple births and represent, for the first time, a striking change in trend when compared with the previous steep 4-fold increase since the early 1980s. However, the incidence of other multiples--twins--continued to escalate. The most probable reasons for this change are new embryo transfer guidelines and availability of multi-fetal pregnancy reduction procedures. Because actual numbers of higher-order multiples are by far lower than the number of twins, and because twins are predictably associated with significant perinatal morbidity and mortality, the implications of the ever-increasing multiple birth rates are no less alarming. As long as the incidence of twins is not reduced, the decreasing incidence of higher-order multiples, per se, does not herald the end of the epidemic of multiple births.

Embryo Transfer↗

PubMed2005

Spontaneous embryonic loss rates in twin and singleton pregnancies after transfer of top- versus intermediate-quality embryos.

OBJECTIVE: To determine whether embryo quality is associated with early spontaneous loss rates in twin and singleton pregnancies after IVF/intracytoplasmic sperm injection (ICSI). DESIGN: Retrospective, single center analysis. SETTING: The Center of Reproductive Medicine, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. PATIENT(S): Women undergoing IVF/ICSI and two- or three-embryo transfer of intermediate- and top-quality embryos. INTERVENTION(S): First-trimester sonography at 6 to 7 weeks to determine number of embryos with positive heartbeat. Number of embryos lost was calculated from a second-trimester sonogram. MAIN OUTCOME MEASURE(S): Rates of total pregnancy loss, as related to embryo quality, initial number of embryos, maternal age <35 or > or =35 years, and IVF procedure. RESULTS: A total of 94 losses (23.1% of 407 pregnancies) were counted, with similar proportions in pregnancies after transfer of intermediate- or top-quality embryos. Neither the mode of IVF procedure nor the number of transferred embryos affected the loss rate. In contrast, the loss rate was significantly higher in older mothers after transfer of intermediate-quality embryos (odds ratio [OR 2.4], 95% confidence interval [CI] 1.1-5.5). Losses among singletons were significantly higher compared with losses among twins (OR 2.5, 95% CI 1.1-6.0), but this was observed in top-quality embryos only. CONCLUSION(S): Top-quality but not intermediate-quality ETs are associated with lower early spontaneous loss rates among twin pregnancies after IVF/ICSI.

Abortion, Spontaneous↗

PubMed2005

Down syndrome screening in multiple pregnancies.

First or second trimester screening in twin pregnancies is feasible and still efficacious by using either a combination of ultrasound and maternal serum biochemistry in the first trimester or maternal serum biochemistry in the second trimester. Special care, however, should be emphasized in what concerns biochemical screening, since it is much less sensitive in multiples. These "pseudo-risks" have been challenged for their scientific and clinical validity, however. Until more data are available from larger studies on the distribution of markers in concordant or discordant twins, nuchal translucency estimated for each fetus should be the predominant factor by which women who present with increased risk should be counseled regarding invasive testing. In dizygotic pregnancies, pregnancy-specific risk should be calculated by summing the individual risk estimates for each fetus. In monozygotic twins, the risk should be calculated based on the geometric mean of both nuchal translucency measurements, not forgetting that the false-positive rate of nuchal translucency screening is expectantly higher than in singletons.

Biomarkers↗

PubMed2005

Growth aberration in multiple pregnancy.

Growth of twins and higher-order multiples is an exceptional metabolic challenge for the expecting mother. She is doing much more than a mother of a singleton in terms of nurturing, however. Metabolic requirements need adequate dietary intervention in the form of increased weight gain during early pregnancy. It is normal for multiples to be smaller than singletons. Being smaller than singletons does not necessarily mean that multiples are pathologically growth restricted. It is important to remember that twins and triplets have different growth patterns, and their growth should not be considered by using singleton standards. When a small-for-gestational-age fetus is suspected in a multiple pregnancy, it is advisable to follow or to treat the pregnancy as if it was an SGA singleton.

Birth Weight↗