Perinatal outcome of ICSI pregnancies compared with a matched group of natural conception pregnancies in Flanders (Belgium): a cohort study

A retrospective cohort study was conducted with an intracytoplasmic sperm injection (ICSI) group and a naturally conceived comparison group. A total of 1655 singleton and 1102 twin ICSI births were studied with regard to perinatal outcome. Control subjects (naturally conceived pregnancies) were selected from a regional registry and were matched for maternal age, parity, place of delivery, year of birth and fetal sex. The main outcome measures were duration of pregnancy, birth weight, Apgar score <5 after 5 min, neonatal complications, perinatal death and congenital malformations. Twin births, when compared with singletons, carry a much higher risk of poor perinatal outcome. For both ICSI singletons and ICSI twins, no significant difference was found between ICSI and naturally conceived pregnancies for all investigated parameters. After excluding like-sex twin pairs, ICSI twin pregnancies were at increased risk for perinatal mortality (OR = 2.74, CI = 1.26-5.98), prematurity (OR = 1.38, CI = 1.10-1.75) and low birth weight (OR = 1.34, CI = 1.06-1.69) compared with spontaneously conceived different-sex twin pairs. In conclusion, the perinatal outcome of ICSI singleton and twin pregnancies was very similar to that of spontaneously conceived pregnancies in this large cohort study. After excluding like-sex twin pairs, ICSI twins were at increased risk for prematurity, low birth weight and higher perinatal mortality compared with the natural conception comparison group.     

Prospective risk of fetal death in singleton, twin, and triplet gestations: implications for practice

OBJECTIVE: To evaluate the prospective risk of fetal death in singleton, twin, and triplet pregnancies and to compare this risk with fetal and neonatal death rates. METHODS: We analyzed 11,061,599 singleton, 297,622 twin, and 15,375 triplet gestations drawn from the 1995-1998 National Center for Health Statistics linked birth and death files. Prospective risk of fetal death was expressed as a proportion of all fetuses still at risk at a given gestational age and compared with fetal death rate. Fetal death risk and neonatal death rates were represented graphically for singletons, twins, and triplets. RESULTS: The prospective risk of fetal death at 24 weeks was 0.28 per 1000, 0.92 per 1000, and 1.30 per 1000 for singletons, twins, and triplets, respectively. At 40 weeks, the corresponding risk was 0.57 per 1000 and 3.09 per 1000 for singletons and twins, respectively and, at 38 or more weeks, 13.18 per 1000 for triplets. Plots of gestation-specific prospective risk of fetal death and neonatal mortality converged for singletons and twins at term but crossed for triplets at approximately 36 weeks' gestation. CONCLUSION: Prospective risk of fetal death is greater for triplets and twins than for singletons and greater for triplets than for twins during the third trimester. The pattern corroborates with uteroplacental insufficiency as a suspected underlying mechanism. When prospective risk of fetal death exceeds neonatal mortality risk, delivery might be indicated. When this model is used, this data set suggests that it might be reasonable to consider delivery of twins by 39 weeks and triplets by 36 weeks to improve perinatal outcome.     

Contribution of Gestational Age and Birth Weight to Perinatal Viability in Singletons Versus Twins

The objective of this study was to determine the effects of birth weight and gestational age on twin vs. singleton mortality. Population-based analysis of live births, fetal deaths, and infant deaths by plurality in the United States from 1983 to 1986 was conducted. Seven mortality rates and relative risks (RRs) of twin vs. singleton mortality were calculated by birth weight, gestational age, and combined birth weight and gestational age. The mortality rates included fetal, perinatal, early neonatal, late neonatal, neonatal, postneonatal, and infant. Twins had 3–4 times the RRs of mortality compared to singletons, ranging from a RR of 2.71 for postneonatal mortality to a RR of 3.73 for late neonatal mortality. Generally, for birth weights of 2,800 g or less and gestational ages of 38 weeks or less, twins had lower combined birth weight and gestational age mortality rates and lower RRs. Between 1,900 and 2,799 g, mortality rates decreased then increased with advancing gestation between 31 and 42 weeks both more severely and consistently for twins than for singletons. In conclusion, twins have lower birth weight and gestational age-specific mortality rates and RRs than singletons below 2,800 g and 39 weeks. The “U”-shaped pattern of mortality beyond 38 weeks gestation, particularly for twins with birth weights below 2,500 g, reflects the combined influence of growth retardation and advancing gestation on mortality. The lowest mortalityfor twins is achieved at birth weights of 2,500-2,799gat35-38 weeks gestation. Only 1 in 7 twins is born within this “ideal window.” Efforts at reducing twin mortality should be directed toward reducing intrauterine growth retardation and achieving optimal timing for delivery.     

The Outcome of Twin Pregnancies in Dunedin 1968–1978

Summary: Of 14,473 pregnancies in Dunedin City between 1968 and 1978, 1.07% were twin (1 in 93.4 pregnancies). Perinatal mortality has decreased over this period for both twins and singletons. To examine the hypothesis that the tendency for twins to be preterm and small for gestational age explained their increased mortality and morbidity, groups of twins and singletons of like birth-weight and gestational age were compared. No significant differences were found, suggesting that birth-weight and gestational age are the major determinants of outcome, and that a twin should fare no worse than a singleton of similar birth-weight and gestational age.     

Effect of prolongation of pregnancy on perinatal mortality

Objectives: (1) To determine the distribution of singleton and twin births according to gestational age in a Nigerian obstetric population; and (2) to compare their perinatal outcomes according to gestational age. Methods: A 10-year retrospective comparative study of twin and singleton births at a tertiary care center in Enugu, Nigeria. The variables analyzed were: the proportion of deliveries occurring at each gestational age, the gestational age-specific rates for stillbirths, cesarean section, babies with 1-min Apgar scores less than 4 and those whose birthweights were below the 10th percentile for gestational age. The trends in these rates were determined by finding the best fitting polynomial regression curve for each variable. Tests of statistical significance for trends in proportions were carried out by means of the χ²-test at the 95% confidence level. Results: Of the 496 twin births, 3.6% compared with 17.3% of the 496 singleton births went beyond 40 weeks’ gestation while 1.2% of the twin and 4.4% of the singleton deliveries occurred at 42 weeks’ gestation or beyond. For twins as well as singletons, there was a consistent and significant decline in the stillbirth rate and the proportion of babies with 1-min Apgar scores less than 4 up to 42 weeks (P=0.0000). Among the twins, the proportion of babies with birthweights below the 10th percentile (i.e. those with impaired growth) significantly rose from 28 weeks and above (P=0.0000) while among the singletons, a declining trend with gestational age was observed (P=0.0003). However, among the twins with impaired growth, the stillbirth rate neither differed between the first and second twins at each gestational age nor did it increase with gestational age in both the first and second twins. While the cesarean section rate for singletons remained almost stable at approximately 13%, there was a significant rise in the cesarean section rate with gestational age among the twin births. Conclusions: There were 1.2% of twin deliveries compared with 4.4% of singleton deliveries which occurred at 42 weeks’ gestation or beyond. In the Nigerian population studied, the perinatal outcomes in twins did not differ from those of singletons up to 42 weeks’ gestation suggesting that the 42-week cut-off for prolonged pregnancy applies equally well to twins as to singletons.     

Risk of fetal loss in twin pregnancies undergoing second trimester amniocentesis(1)

OBJECTIVE: To assess the rate of fetal loss among bichorionic twin gestations undergoing genetic amniocentesis compared with singletons undergoing the procedure and untested twins. METHODS: In a retrospective cohort study, three groups were compared: 476 women with twins undergoing amniocentesis, 489 women with singleton gestations undergoing amniocentesis, and 477 women with twins presenting at a similar gestational age for ultrasound studies only. All subjects were scanned at 17-18 weeks' gestation and again approximately 4 weeks after the procedure or first ultrasound scan. Excluded were twin pregnancies after fetal reduction or chorionic villus sampling, fetuses with structural anomalies, and cases in which one fetus had died at the time of examination or after fetal reduction. RESULTS: Thirteen twin gestations in the tested group (2.73%) aborted spontaneously up to 4 weeks after the procedure compared with three twin controls (0.63%, P =.01) and three post-procedure singleton controls (0.6%, P =.01). An abnormal karyotype was discovered in 15 tested twin pregnancies (3%) and in six tested singletons (1.23%). All affected twin pairs were discordant for the chromosomal anomaly. CONCLUSION: The risk of early fetal loss in twins undergoing amniocentesis appears to be higher than that of exposed singletons or unexposed twins.     

Cesarean delivery for twins: a systematic review and meta-analysis

OBJECTIVE: We undertook a systematic review and meta-analysis to determine whether a policy of planned cesarean section or vaginal delivery is better for twins. STUDY DESIGN: We searched MEDLINE and EMBASE from 1980 through May 2001 using combinations of the following terms: twin, delivery, cesarean section, vaginal birth, birth weight, and gestational age. Studies that compared planned cesarean section to planned vaginal birth for babies weighing at least 1500 g or reaching at least 32 weeks' gestation were included. We computed pooled odds ratios for perinatal or neonatal mortality, low 5-minute Apgar score, neonatal morbidity, and maternal morbidity. The infant was the unit of statistical analysis. Results were considered statistically significant if the 95% CI did not encompass 1.0. RESULTS: We retrieved 67 articles, 63 of which were excluded. Four studies with a total of 1932 infants were included in the analysis. A low 5-minute Apgar score occurred less frequently in twins delivered by planned cesarean section (odds ratio, 0.47; 95% CI, 0.26-0.88) principally because of a reduction among twins if twin A was in breech position (odds ratio, 0.33; 95% CI, 0.17-0.65). Twins delivered by planned cesarean section spent significantly longer in the hospital (mean difference, 4.01 days; 95% CI, 0.73-7.28 days). There were no significant differences in perinatal or neonatal mortality, neonatal morbidity, or maternal morbidity. CONCLUSION: Planned cesarean section may decrease the risk of a low 5-minute Apgar score, particularly if twin A is breech. Otherwise, there is no evidence to support planned cesarean section for twins.     

Second-trimester maternal serum free-beta-human chorionic gonadotropin and alpha-fetoprotein levels in normal twin and singleton pregnancies: a report of local Chinese population

OBJECTIVES: The study evaluated the differences between Chinese normal twin and singleton pregnancies in the levels of maternal serum free-beta-human chorionic gonadotropin (free beta-hCG) and alpha-fetoprotein (AFP) used in second-trimester Down syndrome (DS) screening. METHODS: The concentrations of maternal serum markers of 456 twin pregnancies and 12 067 singleton controls in gestational 15 to 20 weeks were measured by time-resolved fluoroimmunoassay, and the levels of markers were compared between the twins and singletons. RESULTS: Significant differences were found between the levels of free beta-hCG in twins and twice of those in singletons in 16, 17 and 19 gestational weeks (p < 0.05 for all); while considering AFP, significant differences were found in 16 and 19 gestational weeks (p < 0.05 for both). No correlations were found in twins between the levels of markers and maternal weights in most gestational weeks (Free beta-hCG: p > 0.05 for 15 to 18 and 20 gestational weeks; AFP: p > 0.05 for 16 to 20 gestational weeks). CONCLUSIONS: The Chinese gestational age-specific levels of maternal serum markers in normal twins are not twice as those in singletons. The current weight-correction model for DS screening may be not feasible for twins.     

Perinatal outcome of singleton versus twin late preterm infants: do twins mature faster than singletons?

Objective: To determine whether as a result of an assumed advanced maturation late preterm twin infants have a more favorable perinatal outcome than singleton late preterm infants.

Methods: Over a 36-month period (from September 2011 to September 2014), 277 late preterm infants (153 from singleton and 124 from twin pregnancies) were hospitalised in NICU, University Hospital Center “Sisters of Mercy” Zagreb, Croatia, and were retrospectively studied by review of maternal and neonatal charts for gestational age, sex, birth weight, mode of delivery, 5-min Apgar score and for several outcome variables expected for preterm infants, until the day of discharge.

Results: There was statistically no significant difference in the incidence of any of the observed and compared outcomes, except in the incidence of phototherapy which was higher in singletons group (49.01 versus 13.7%, p?<?0.0001). The mean birth weight, as expected, was smaller in the twin group. Conclusions: We found no evidence to support the traditional belief that twin late preterm infants have accelerated maturation and better neonatal outcome compared with singleton late preterm infants. Our findings suggest that late preterm twins have a prognosis similar to that of singleton late preterm infants born at the same gestational age.     

The Principal Pregnancy Complications Resulting in Preterm Birth in Singleton and Twin Gestations

Preterm birth is the major cause of perinatal mortality for both singleton and twin gestations in the United States; most preterm birth prevention programs are primarily structured to detect and treat preterm labor. Most of these programs have had limited success, and the preterm birth rate for twins has remained well above that for singletons. Little attention has been paid to the question of whether the frequency of conditions that result in preterm twin delivery differs from those that result in the delivery of preterm singletons. Delivery records were reviewed for all 1,976 preterm (24–36 completed gestational weeks) singleton pregnancies and 221 preterm twin pregnancies delivered at the University of Connecticut Health Center, 1980–1989, to determine the primary complication that resulted in preterm delivery. Premature rupture of membranes was responsible for 46% of these singleton preterm deliveries, while the other causes were preterm labor with intact membranes (20%), pregnancy-induced hypertension (15%), antepartum hemorrhage (9%), and other maternal-fetal indications (10%). The five groups differed significantly in maternal and neonatal characteristics. The principal pregnancy complications resulting in preterm delivery of twins were preterm rupture of membranes (42%), preterm labor (31%), antepartum hemorrhage (4%), pregnancy-induced hypertension (11%), and other maternal-fetal indications (12%). Compared to preterm singletons, the preterm twins were significantly more likely to deliver because of preterm labor and less likely to deliver because of hemorrhage. Substantial reduction in the preterm birth rate requires programs tailored to the specific population and etiologies involved and should not solely address preterm labor.     

Perinatal outcome and peripartum complications in preterm singleton and twins deliveries: a comparative study

OBJECTIVE: Multiple pregnancy is one of the major risk factors for preterm births. The aim of the present study was to compare perinatal outcome and peripartum complications between twins and singletons, born preterm. STUDY DESIGN: The study population consisted of preterm deliveries of 435 pairs of twins (870 neonates) and the comparison group included 4754 preterm deliveries of singletons, born in the same period (January 1, 1989-December 31, 1996). Exclusion criteria were lack of prenatal care and births following infertility treatments. The three steps in statistical analysis consisted of (1) degree of concordance between the twins; (2) comparison between each twin (I and II) to their singleton comparison groups using SPSS computer program; (3) stratified analysis to examine perinatal mortality rates at different gestational age groups. RESULTS: The prevalence of preterm deliveries was 7.9% (6192/77610). Perinatal mortality was lower in twins of both birth orders, however, it was statistically significant only when APD is considered. Mortality rates in all gestational age groups and for both twin groups were lower than that of singleton [OR=0.45 (0.26-0.75; 95% CI) for twin-I; OR=0.36 (0.21-0.59; 95% CI) for twin-II]. Compared to singletons, twin gestations had less congenital malformations. Twin gestation had statistically lower rates of preterm premature rupture of membranes, severe pregnancy induced hypertension, oligohydramnios, placenta previa, placental abruption and clinical chorioamnionitis [12.2 vs.17.3%, 2.5 vs. 6.3%, 2.3 vs. 4.7%, 0.9 vs. 2.9%, 1.8 vs. 5%, 1.8 vs. 5.2%, respectively (P<0.01)]. Mothers of twins had less diabetes mellitus class B-R, hydramnios and chronic hypertension than that of singleton (1.8 vs. 2.6%, 5.5 vs. 7.4%, 3.7 vs. 4.8%, respectively). Cesarean section rates were significantly higher in twin's gestation. Mothers of twins tended to be older and of higher birth and gravidity order. CONCLUSIONS: Perinatal mortality rates and peripartum complications were lower in twin compared to singleton gestations.     

A case-control comparison of the effectiveness of betamethasone to prevent neonatal morbidity and mortality in preterm twin and singleton pregnancies

We compared the effectiveness of antenatal betamethasone for the prevention of neonatal morbidity and mortality in preterm twin and singleton gestations. We conducted a case-control study of women with twin versus singleton gestations who received betamethasone for risk of prematurity in a university-affiliated, community-based, tertiary care center between 1997 and 2005. Cases were identified from clinical care and pharmacy databases, then matched for neonatal gender and gestational age (GA) at delivery. Sixty cases and 60 controls of deliveries occurring between 24 and 34 weeks' gestation were identified. The mean GA was 30.4 +/- 2.7 weeks. There were no differences between the groups in maternal demographics (with the exception of maternal age), birth weight, head circumference, Apgar scores, need for mechanical ventilation, days on ventilator, intraventricular hemorrhage grade 3 or 4, necrotizing enterocolitis suspected sepsis, total days in neonatal intensive care unit, or neonatal deaths. No differences in major morbidities or mortality were found in singletons versus twins. Concerns that the added maternal plasma volume in multiple gestations could lessen the neonatal benefits of antenatal betamethasone were not substantiated. This study may be affected by beta-error due to small sample size and sampling bias as a result of a retrospective study.     

Comparison of active phase labor between triplet, twin, and singleton gestations

OBJECTIVE: To characterize the active phase of labor in triplet pregnancies and compare it with gestational age-matched twins and singletons. METHODS: Active phase rates were calculated beginning at 5 cm of dilation for women with triplet gestations longer than 24 weeks who labored and reached the second stage. Twin and singleton cohorts that also completed the first stage of labor were matched for gestational age at delivery (+/-1 week), parity, and epidural use. Intrapartum variables included oxytocin use (induction or augmentation, duration of infusion, and maximum dosage), cervical dilation at membrane rupture, and active phase dilation rate. RESULTS: Thirty-two triplet pregnancies met inclusion criteria between January 1994 and September 1998 and were each compared with twin and singleton cases in a 1:2 ratio. Triplet and twin active phase rates, while similar (1.8 versus 1.7 cm/hour, respectively), were significantly lower than the mean singleton dilation rate (2.3 cm/hour, P =.02). No other intrapartum variables differed between the three groups. Despite controlling for gestational age at delivery, mean birth weights were significantly higher in singletons and correspondingly lower in twins and triplets (2,493 versus 2,112 and 1,968 g, respectively; P =.001). An analysis of active phase dilation rates as a function of the cumulative birth weight per pregnancy demonstrated an inverse correlation, with slower progress in active labor associated with increasing total fetal weight (R = -.24; P =.002). CONCLUSIONS: Triplet and twin active phase dilation proceeds at a slower rate than that observed in singleton pregnancies. The rate of active phase dilation is inversely correlated to total fetal weight.     

Assessment of fetal growth in twins: Which method to use?

Fetal growth restriction contributes to the excess perinatal mortality and morbidity associated with twin pregnancies. Regular ultrasound monitoring for fetal growth restriction is an essential component of antenatal care of twin gestations. It is accepted that twins have divergent growth trajectories around 28–30 weeks’ gestation and are born smaller compared to singletons. Despite this well-established difference in fetal growth, twin pregnancies have been traditionally managed using growth standards developed for singleton pregnancies. Numerous recent studies have demonstrated a strong case supporting the use of twin-specific growth standards, but clinical implementation has been lacking. In this paper, we will review the evidence on factors affecting fetal growth, the rationale for twin-specific reference charts, clinical evidence for their use, and future direction of research. Applying singleton growth standards to twin pregnancies inflates the abnormal growth rate, and recent clinical evidence from several studies suggests that they are too stringent for classification of twins. The association of adverse perinatal and maternal outcomes such as perinatal death, preterm birth, neonatal care unit admission, hypertensive disorders of pregnancy, and composite neonatal morbidity is stronger when classification is made using twin-specific standards compared to singletons.     

A case-control study of 1253 twin pregnancies from a 1982-1987 perinatal data base

In one regional perinatal network between 1982-1987, 101,506 women delivered infants greater than 500 g, of which 1253 were twin pregnancies (1.2%). This latter group was compared statistically with a 5% random sample of the singletons (N = 5119). The results showed that the women with twin pregnancies were slightly older, had a higher parity, gained more weight during the gestation, and had a heavier body weight at delivery. Twin pregnancies were complicated by increases in hypertension (odds ratio 2.5; 95% confidence interval 2.1-3.1), abruption (odds ratio 3.0; 95% confidence interval 1.9-4.7), and anemia (odds ratio 2.4; 95% confidence interval 1.9-3.0). There was no increased risk of pyelonephritis, placenta previa, or diabetes mellitus in mothers with twins. The twin pregnancies delivered earlier and the infants were smaller, had lower Apgar scores, and were at increased risk for congenital anomalies. Fetal and neonatal mortality rates were significantly increased in the twin infants; the perinatal mortality rates for twin A and twin B were 48.8 and 64.1, respectively, compared with 10.4 per 1000 births for the singleton controls. When the twin infants A and B were of similar weight, they had a similar perinatal mortality (odds ratio 1.0; 95% confidence interval 0.6-1.8). For infants less than 2500 g, twins A and B had lower fetal and neonatal mortality rates than did singletons, but twins heavier than 2500 g were at increased risk of perinatal death.     

Neonatal nucleated red blood cell counts in twins

We counted nucleated red blood cells (NRBC) per 100 white blood cells (WBC) in the umbilical cord blood from 98 twins born to 49 women with uncomplicated twin pregnancies at > or = 34 weeks of gestation to better characterize NRBC in twins. Twelve women with monochorionic (MC) placentas and 37 with dichorionic (DC) placentas gave birth at 36.7 +/- .9 and 36.5 +/- 2 weeks of gestation, respectively. All twins were born with an Apgar score of > or = 7 at 1 min. Log10 (NRBC/100 BC) in 98 twins exhibited a nearly normal distribution, and was significantly associated with gestational age for both MC (r = -0.457, p = 0.025) and DC twins (r = - 0.275, p = 0.018), and with birth weight for both MC (r = -0.682, p < 0.001) and DC twins (r = -0.336, p = 0.003). Log10 (NRBC/100 WBC) tended to be larger in smaller twins than in larger twins in the MC group, and significantly larger in smaller twins than in larger twins in the DC group (p < 0.05). Intertwin difference in Log10 (NRBC/100 WBC) was defined as the value of Log10 (NRBC/100 WBC) of the smaller twin minus Log10 (NRBC/100 WBC) of the larger twin, and became greater with increasing intertwin difference in birth weight (r = 0.411, p = 0.003). These findings suggest that neonatal NRBC reflected gestational age and birth weight in twins. This preliminary observation using a small number of twins suggests that the smaller twin may have experienced a relative lack of oxygen compared with the larger twin in utero.     

Neonatal morbidity and mortality associated with triplet pregnancy

Objective: To compare neonatal morbidity and mortality in a large cohort of triplet pregnancies with singleton and twin neonates managed at a single tertiary center over a short time.Methods: Records from all triplet pregnancies managed and delivered from 1992 to 1996 were reviewed for neonatal outcome data. Pregnancies delivered before 20 weeks' gestation and neonates with lethal congenital anomalies were excluded. The comparison group comprised all singleton and twin neonates managed in the same neonatal intensive care unit (NICU) during the same period.Results: During the 5-year period, 55 triplet pregnancies and their resulting 165 neonates were managed and delivered at this center. Their outcomes were compared with those of 959 singleton and 357 twin neonates born at similar gestational ages. The median gestational age at delivery for triplets was 32.1 weeks, and 149 of the 165 infants were admitted. Sixteen triplet neonates were not admitted to our neonatal intensive care unit, 12 because of previable gestational age, three because of stillbirth, and one because of a lethal congenital anomaly. The crude perinatal mortality rate in triplets was 121 per 1000 births, and there was no significant difference in outcome based on triplet birth order. There were no significant differences in survival rates between singleton, twin, and triplet neonates, with an overall neonatal survival of 95%, 95%, and 97%, respectively. The only significant differences in morbidity were an increased incidence of mild intraventricular hemorrhage (relative risk [RR] 6.20; 95% confidence interval [Cl] 2.64, 14.61), mild retinopathy of prematurity (RR 20.05; 95% CI 3.59, 111.79), and severe retinopathy of prematurity (RR 46.69; 95% CI 6.25, 348.85) in triplets compared with singletons, and severe retinopathy of prematurity (RR 6.83; 95% CI 1.24, 37.56) in triplets compared with twins.Conlusion: When stratified by gestational age, triplet neonates delivered at 24–34 weeks' gestation have similar outcomes as singleton and twin neonates, with the only clinically significant difference being an increased incidence of retinopathy of prematurity in triplets.     

Neurodevelopmental outcomes of twins

In population-based studies, the prevalence of neurodevelopmental disability is consistently higher in twins than singletons. This is largely because birth weight and gestational age (GA) distributions of twin births are shifted to the left when compared with singleton births, and lower birth weight and lower GA are associated with increased risk of neurodevelopmental disability. From a pathophysiologic perspective, a question of interest is whether neurodevelopmental outcomes of twins differ from singletons after controlling for covariates. If significant differences in outcomes persist, this would suggest that the twining process itself or something intrinsic to shared life in the womb may be responsible for observed differences. From a clinical perspective, when counseling parents at risk for preterm delivery of twins, it is useful to understand how twin outcomes compare relative to singleton outcomes at the same birth weight or GA. The purpose of this review is to examine the long-term neurodevelopmental outcomes of twins compared with singletons with control for important covariates.     

Gestational diabetes mellitus: metabolic and blood glucose parameters in singleton versus twin pregnancies.

OBJECTIVES: This study compared the frequency, glucose tolerance test results, and parameters of blood glucose control in twin and singleton pregnancies associated with gestational diabetes mellitus and carbohydrate intolerance. STUDY DESIGN: Twin and singleton pregnancies associated with gestational diabetes mellitus and carbohydrate intolerance were compared as follows: frequency, maternal age, weight, 1-hour screen, glucose tolerance test results, posttreatment blood glucose values, insulin requirement, and insulin dose. Statistical analysis included the chi(2) and Student t tests. RESULTS: Gestational diabetes mellitus was increased in twins (7.7% vs 4.1%; P <.05). The maternal weight at first visit was significantly less, and the 3-hour glucose tolerance test value was significantly greater than that for singletons. The other parameters were not different. CONCLUSIONS: There is a significant increase in the incidence of gestational diabetes mellitus and disturbance of the 3-hour glucose tolerance test in twin pregnancies. However, insulin requirements were not different, suggesting a mild disturbance of carbohydrate tolerance that was effectively managed by the strategies used to achieve blood glucose control in singletons.