Monochorionicity in perspective.
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Female↗
Biomedical subjects
I Blickstein
Publications and source records attributed to I Blickstein.
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.
Female↗
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.
Abortion, Spontaneous↗
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.
Birth Order↗
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.
Cerebral Palsy↗
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.
Analysis of Variance↗
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.
Abortion, Spontaneous↗
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.
Blood Gas Analysis↗
The interplay between ethnicity and free access to perinatal care.
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Female↗
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.
Birth Weight↗
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.
Age Factors↗
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.
Delivery, Obstetric↗
Spastic diplegia is not associated with intrapartum hypoxia.
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Cerebral Palsy↗
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.
Adult↗
[Cesarean section upon maternal request].
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Cesarean Section↗
[Dr. Virginia Apgar--1909-1974].
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Anesthesiology↗
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.
Cross-Sectional Studies↗