Is the obstetric outcome of in vitro fertilized singleton gestations different from natural ones? A controlled study

Objective: To determine whether singleton IVF pregnancies carry adverse maternal or fetal outcome when compared with naturally conceived gestations.

Design: An analysis of the obstetric outcome of singleton IVF pregnancies in comparison with matched, naturally conceived singleton controls. Setting: In vitro fertilization unit and obstetric service at a tertiary medical center.

Patient(s): Two hundred sixty consecutive singleton IVF pregnancies and 260 naturally conceived singleton controls matched 1:1 for maternal age, parity, ethnic origin, and location and date of delivery.

Intervention(s): In vitro fertilization-ET.

Main Outcome Measure(s): The rate of antenatal obstetric complications, nonvertex presentation, cesarean section, preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality.

Result(s): The rates of most antenatal complications were similar in both groups. Urinary tract infection was the only complication diagnosed significantly more frequently after IVF (7.3% versus 1.2%); however, the rates of severe urinary tract infection necessitating hospitalization were similar. The incidence of nonvertex presentation was also similar. The cesarean section rate was significantly higher among IVF patients (41.9% versus 15.5%). The rates of preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality were comparable.

Conclusion(s): When controlling for maternal age, parity, ethnic origin, and location and date of delivery, singleton IVF pregnancies do not carry an increased risk for prematurity, low birth weight, or maternal or fetal complications. Still, these pregnancies are associated with a high rate of cesarean sections.     

Medical and economic effects of twin gestations

OBJECTIVE: To determine the incidence and trends of twinning in the United States and to review the medical and economic effects of twin versus singleton gestations. METHODS: Pertinent and recent studies on twin gestations were obtained through a MEDLINE database search of the English language between December 1987 and December 1999. Data from the 1995-1996 National Center for Health Statistics were also used to compare gestational age at delivery, fetal growth restriction, and perinatal mortality for twin and singleton gestations. Studies that have evaluated perinatal risks in relation to advanced reproductive technology also were reviewed and summarized. The economic implications of twinning from a societal perspective and infant quality of life issues of twins compared with singleton gestations are reviewed. RESULTS: Due to delayed childbearing and increased use of reproductive technologies, the incidence of twin gestations in the United States has been increasing. Twin pregnancies have a higher risk of complications, including pregnancy-induced hypertension, anemia, antepartum and postpartum hemorrhage, and maternal mortality. In addition, twin infants are more likely to deliver preterm, have low birth weight and greater perinatal mortality rates. These outcomes influence health care costs and quality of life for both parents and children. CONCLUSIONS: Women carrying twin fetuses are at increased risk for perinatal and obstetric complications. The increased perinatal risks that accompany twin fetuses may be partly due to the increasing use of advanced reproductive technologies. The economic burdens, as well as the potential for decreased quality of life among twins, needs careful evaluation.     

Morbidity and mortality of preterm twins and higher-order multiple births.

OBJECTIVE: To determine if preterm infants of higher-order multiple (HOM) gestations have a significantly worse outcome during hospital stay when compared with preterm twins. STUDY DESIGN: Retrospective cohort analysis. METHODS: Perinatal outcome variables including gestational age (GA), birthweight, prenatal steroid use, cesarean section delivery rate, Apgar scores, and growth retardation were analyzed for 106 preterm HOM births (triplets and quadruplets) versus 328 preterm twins admitted to a single tertiary level neonatal intensive care unit. A comparison of the mortality and major neonatal morbidities such as respiratory distress syndrome, patent ductus arteriosus, intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, and retinopathy of prematurity was made for these two groups. In addition, the duration of respiratory support including surfactant therapy, nasal continuous positive airway pressure, and mechanical ventilation, as well as the length of hospitalization, was analyzed. RESULTS: There were no significant differences in major morbidities between the infants of HOM and twin births of similar GA. There was no statistically significant difference in mortality, but the data showed a trend for lesser mortality in HOM. There was a highly significant increase in antenatal steroid use as well as the use of cesarean section for delivery in the HOM when compared with twin gestations. The infants of HOM gestations were of significantly lower birthweight than the twins and had a longer hospitalization. CONCLUSION: Although premature infants of HOM had lower birthweight and needed a longer hospital stay, their mortality and morbidity at hospital discharge were not worse than that for preterm twins.     

Very-low-birthweight neonates: do outcomes differ in multiple compared with singleton gestations?

The purpose of this study is to determine if outcomes for very-low-birthweight (VLBW) neonates differ in multiple versus singleton gestations. This is a retrospective cohort study of neonates weighing less than 1500 g admitted to a neonatal intensive care unit from 1993 to 2004. Outcome variables were necrotizing enterocolitis, death, and/or severe intraventricular hemorrhage (IVH). Statistical analysis included univariate and multivariate analysis. During the study period, 1769 VLBW infants including 465 multiples and 1304 singletons were identified. Gestational age and birthweight were similar; conversely white race (68% multiples versus 43% singletons), maternal age (28.7 +/- 5.7 versus 26.1 +/- 6.5 years), born at facility (95% versus 86%), antenatal steroids (74% versus 58%), preeclampsia (14% versus 24%), and preterm labor (74% versus 62%) were significantly different. Correcting for these, VLBW multiples had a higher odds ratio (OR) of death and/or severe IVH, OR 1.4 (1.03-1.95). In our population, VLBW multiple gestations were at elevated odds for death and/or severe IVH compared with VLBW singletons.     

Fetale Mangelentwicklung bei Geminigravidität

Twin gestations are high risk pregnancies and require intensified antenatal care. There is an increased fetal and maternal morbidity and mortality compared to singleton gestations. As perinatal complications among twin gestation depend on varying membrane and placental arrangements, early differentiation between dichorionic-diamniotic, monochorionic-diamniotic and monochorionic-monoamniotic twin gestation is a crucial task. Therefore routine sonographic determination of chorionicity and amnionicity is highly recommended. Intrauterine growth restriction is observed in 9% to 26% of twin pregnancies, with a higher proportion of SGA fetuses in monochorionic compared to dichorionic twins. SGA twins have a 2.4-fold higher perinatal mortality than AGA twins. Discordant fetal growth (≥ 20% weight discordance) has been reported to occur in 23% to 35 % of twin pregnancies and is associated with adverse perinatal outcome.     

The association of antenatal corticosteroids with neonatal hypoglycemia and hyperbilirubinemia

Abstract

Objective: While antenatal corticosteroids reduce the risk of neonatal morbidity and mortality, perhaps the maternal hyperglycemia they produce has other neonatal effects. Thus, we sought to examine the association between antenatal betamethasone exposure and neonatal hypoglycemia and hyperbilirubinemia.

Methods: We designed a retrospective cohort study of all preterm deliveries from 32 to 37 weeks of gestation at a single university hospital from 1990 to 2007. Data were collected on antenatal betamethasone administration and the neonatal outcomes. Univariable, multivariable and stratified analyses were conducted.

Results: Of 6675 preterm deliveries, significantly higher rates of neonatal hypoglycemia (5.7% versus 4.2%, p?<?0.05) and hyperbilirubinemia (45.9% versus 24.1%, p?<?0.05) were observed in neonates exposed to antenatal betamethasone. Controlling for potential confounders including gestational age, these findings persisted with betamethasone-exposed neonates 1.6 times more likely to have hypoglycemia (aOR 1.60, 95% CI 1.24–2.07) and 3.2 times more likely to have hyperbilirubinemia (aOR 3.23, 95% CI 2.92–3.58).

Conclusions: Antenatal betamethasone was associated with neonatal hypoglycemia and hyperbilirubinemia. Further work to determine whether this association is related to maternal hyperglycemia should be conducted, given this could be addressed with strict maternal glycemic control during betamethasone administration.     

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.     

Is discordant growth in twins an independent risk factor for adverse neonatal outcome?

OBJECTIVE: To estimate whether discordant growth is associated with adverse perinatal outcomes in twins after adjusting for growth restriction. METHODS: This was a retrospective, hospital-based cohort study of twin gestations with 2 live births delivered at 24 weeks or later from 1992 to 2001. Twin gestations were classified as small for gestational age (SGA) if one or both infants was less than the 10th percentile at birth by singleton Brenner norms and discordant if there was a 20% or more weight discordance. RESULTS: Of 1318 twin pairs, 856 were appropriate for gestational age (AGA) and concordant, 70 pairs were AGA and discordant, 254 pairs were SGA and concordant, and 138 pairs were SGA and discordant. The 4 groups had similar maternal demographics and medical comorbidity. When adjusting for chorionicity, antenatal steroid use, oligohydramnios, preeclampsia, and gestational age at delivery, discordant twins were more likely to have a cesarean delivery (odds ratio 1.87; 95% confidence interval 1.22, 2.87) and to be associated with some adverse neonatal outcomes (low and very low birthweight, neonatal intensive care unit admission, neonatal oxygen requirement and hyperbilirubinemia) independent of SGA status. A statistically nonsignificant trend (odds ratio 2.4; 95% confidence interval 0.99, 6.01) toward higher rates of intraventricular hemorrhage was noted in discordant twins, and no difference was seen for ventilator requirement, respiratory distress syndrome, or necrotizing enterocolitis. CONCLUSION: Discordance places twins at increased risk for some adverse perinatal outcomes, whether they are AGA or SGA. Discordance was not an independent risk factor for serious neonatal morbidity or mortality; however, this study was underpowered to detect those differences.     

Perinatal outcome in triplet versus twin gestations

The present study was conducted to determine whether triplet pregnancies are associated with a significantly worse perinatal outcome than twin pregnancies. Maternal and neonatal outcome was evaluated in 15 triplet and twin pregnancies that were matched for maternal age, race, type of medical insurance, delivery mode, parity, and history of previous preterm delivery. Preterm labor occurred significantly more often in triplet than in twin gestations (80 versus 40%), as did preterm delivery (87 versus 26.7%). Triplets had a significantly lower mean birth weight (1720 versus 2475 g) and gestational age at delivery (33 versus 36.6 weeks). In addition, 53.3% of triplet pregnancies but only 6.7% of twin pregnancies had one or more neonates with intrauterine growth retardation. Discordancy also occurred more frequently in triplets than in twins (66.7 versus 13.3%). The mean averaged neonatal hospital stay was significantly higher in triplets (29 versus 8.5 days), and triplets had a fivefold increased risk of requiring neonatal intensive care as compared with twins. However, there were no significant differences between the groups in maternal morbidity or major neonatal complications such as respiratory distress syndrome or intraventricular hemorrhage. We believe that these data will be useful in counseling patients with respect to the anticipated perinatal outcome of triplet pregnancies.     

Neonatal and maternal outcomes in twin gestations > or =32 weeks according to the planned mode of delivery

OBJECTIVE: To determine a possible relationship between neonatal and maternal outcomes in twin gestations and the planned mode of delivery. STUDY DESIGN: A single-centre retrospective cohort study in twins > or =32 weeks of gestational age was performed. Baseline characteristics, and neonatal and maternal outcomes were documented according to the planned mode of delivery: a planned caesarean section or a planned vaginal birth. Statistical analysis was performed using chi-square test. Fisher exact test was used in case correction was needed. RESULTS: During the study period (1999-2002), 164 twins > or =32 weeks were enrolled in the study. In 29 women (17.7%) an elective caesarean section was performed. The remaining 135 twins (82.3%) were allowed to start a vaginal delivery. An emergency or an urgent secondary caesarean section for both twins was performed in 26 women, and in 2 women for twin B only. One twin B baby died during planned vaginal delivery. No significant differences in perinatal mortality and serious neonatal morbidity were found between both groups (10.3% versus 9.6%). Neonatal outcomes in twins A were significantly better than in twins B (2.4% versus 7.3%), independent of the planned mode of delivery. Serious maternal morbidity was not significantly different between both groups (13.8% versus 19.3%), although 2 women in the elective caesarean section group needed a relaparotomy for haemorrhage. CONCLUSION: Our results do not support an elective caesarean section for twin gestations > or =32 weeks. The success rate of vaginal delivery in the planned vaginal birth group was nearly 80%.     

Routine cervical length in twins and perinatal outcomes

A retrospective review of twin gestations was undertaken to evaluate whether routine cervical lengths (CLs) in such instances change pregnancy outcome. Data were collected from the ultrasound database and chart review. Exclusion criteria included twins reduced to singletons, twins not delivering at our institution, and incomplete information. Twin gestations with a CL were compared with those without a CL. Outcomes of interest included gestational age (GA) at delivery, preterm delivery (PTD), antepartum admissions, antepartum length of stay (LOS), cerclage placement, birthweight, neonatal intensive care unit admissions, and neonatal LOS. Two hundred sixty-two patients met inclusion criteria. Of those, 184 had CLs and 78 did not. Comparing the CL to the no-CL group, there were no differences with respect to GA at delivery (34.8 versus 35.3 weeks; p=0.35), antepartum admissions (32.1 versus 23.1%; p=0.16), cerclage placement (7.1 versus 1.3%; p=0.06), or tocolysis use (28.6 versus 21.8%; p=0.26). There was no difference between the two groups with respect to preterm labor (26 versus 19%; p=0.25), PTD < 28 weeks (8.2 versus 3.9%; p=0.21), PTD < 34 weeks (26.1 versus 25.6%; p=0.94), or PTD < 37 weeks (76.1 versus 70.5%; p=0.34). The only significant difference was antepartum LOS (34.5 versus 31.3 days; p< 0.001). There were no differences in neonatal outcomes. Routine CL did not improve perinatal outcome but increased maternal antepartum LOS.     

Neonatal sepsis and death after multiple courses of antenatal betamethasone therapy

OBJECTIVE: This study was undertaken to compare the effects of single versus multiple courses of betamethasone therapy on the frequencies of neonatal outcomes and perinatal infectious morbidity among singleton pregnancies complicated by preterm delivery. STUDY DESIGN: We performed a nonconcurrent prospective analysis of singleton pregnancies delivered between 24 and 34 weeks' gestation after antenatal betamethasone exposure. Patients were categorized into two groups according to betamethasone exposure: (1) two 12-mg doses in a 24-hour interval on admission (single-course group) and (2) repeated dosing after the initial single course (multiple-course group). All patients received prophylactic antibiotics for group B streptococci. Any patients with ruptured membranes for >24 hours before delivery were excluded. Data were analyzed with the Student t test, the chi(2) test, and the Fisher exact test. Multiple logistic regression analyses were performed to examine the effect of each steroid dosing regimen on early-onset neonatal sepsis and neonatal death. P <.05 was considered significant for all 2-tailed tests. RESULTS: A total of 453 patients were included, with 267 in the single-course group and 186 in the multiple-course group. The two groups were similar with respect to maternal demographic characteristics, gestational age at delivery, mode of delivery, birth weight, and maternal group B streptococcal colonization. Multiple courses were significantly associated with early-onset neonatal sepsis (odds ratio, 5.00; 95% confidence interval, 1.3-23. 2), chorioamnionitis (odds ratio, 9.96; 95% confidence interval, 2. 1-64.6), endometritis (odds ratio, 3.61; 95% confidence interval, 1. 7-8.1), and neonatal death (odds ratio, 2.92; 95% confidence interval, 1.3-6.9). The frequencies of the other neonatal outcomes analyzed, including respiratory distress syndrome and grade III or IV intraventricular hemorrhage, were similar between the 2 groups. Multiple logistic regression analyses confirmed that multiple courses of antenatal betamethasone were independently associated with early-onset neonatal sepsis (odds ratio, 1.25; 95% confidence interval, 1.1-1.9) and neonatal death (odds ratio, 1.70; 95% confidence interval, 1.1-1.9). CONCLUSIONS: Multiple courses of antenatal betamethasone are associated with increased risks of perinatal infectious morbidity and neonatal death.     

Single versus repeated-course antenatal corticosteroids: outcomes in singleton and multiple-gestation pregnancies

The objectives of this study are to compare the neonatal risks and benefits of antenatal single-course versus repeated-course corticosteroids in singleton and multiple-gestation pregnancies. A comprehensive analysis was performed of the inpatient records of all neonates admitted to our center from 1 January 1994 through 31 May 1999. The primary outcome measure was survival without chronic lung disease (CLD). Secondary outcome measures included birth weight; head circumference; interval weight ratios; respiratory disease severity; intraventricular hemorrhage rate and severity; severe retinopathy of prematurity; early infection; and hospital days. All singletons 27-32 completed weeks' gestation, and multiples 26-32 weeks' gestation, whose mothers had received betamethasone before delivery, were included. One hundred and fifteen singleton and 53 multiple-gestation infants (total 168) were stratified by multiplicity, gestational-age (< or =29 or > or =30 weeks), and number of steroid courses. Repeated courses of antenatal betamethasone were not associated with greater survival without CLD, in either singleton- or multiple-gestation infants. In singletons there was no difference in any outcome measure between groups. In multiples, the only difference was greater postnatal weight gain in the lower gestation group. Mean birth head circumference was smaller in repetitively-treated singletons < or =29 weeks. There are no clinically significant neonatal benefits of repeated-course antenatal steroids in singletons > or =27 weeks estimated gestational age (EGA) or multiple-gestation infants > or =26 weeks EGA. Prospective randomized trials of single-course versus repetitive antenatal corticosteroid therapy are warranted.     

Stillbirth and neonatal outcomes in South Australia, 1991-2000

OBJECTIVES: The purpose of this study was to determine the effect of maternal factors associated with impaired placental function on stillbirth and neonatal death rates in South Australia. STUDY DESIGN: From 1991 to 2000, the South Australian Pregnancy Outcome Unit's population database was searched to identify stillbirths and neonatal deaths in women with maternal medical conditions during pregnancy and in twin and singleton pregnancies. RESULTS: Women with hypertension and carbohydrate intolerance and who smoked during pregnancy had an increased risk of stillbirth. Women with twin pregnancies had a significantly higher stillbirth rate than for singletons at each week of gestational age. An increase in stillbirth rate at later gestations was seen with singletons, with a similar trend in twins but rising from 36 weeks' gestation. CONCLUSION: There is a clinical correlation between maternal factors associated with impaired placental function and increased risk of stillbirth, suggesting that intrauterine fetal death represents the mortality end point in a spectrum of intrauterine hypoxia.     

Aggressive perinatal care for high-order multiple gestations: Does good perinatal outcome justify aggressive assisted reproductive techniques?

OBJECTIVE: The purpose of this study was to determine the factors that must be considered for appropriate counseling of patients with high-order multiple gestations.Study Design: A retrospective chart review was carried out from all high-order multiple gestations that were managed by a single perinatology group from February 1993-June 1998. Twin pregnancies that did not result from fetal reduction procedures were used as a control group. RESULTS: Clinical outcome data were analyzed from 9 quadruplet, 25 triplet, 19 reduced twin, and 24 nonreduced twin pregnancies. Women with quadruplet pregnancies were admitted more frequently at an early gestational age, the infants were delivered earlier, and the maternal and neonatal hospital days were longer than for triplet and reduced and nonreduced twin gestations. Triplet pregnancies had an earlier gestational age at delivery (32.3 vs 34.2 weeks), a higher incidence of preterm labor (87% vs 68%), and a higher percentage of neonatal intensive care unit admissions (94% vs 59%) than reduced twin gestations. Reduced twins were hospitalized longer (16.4 vs 9.8 days), were delivered earlier (34.2 vs 36.2 weeks), had a higher incidence of preterm labor (68% vs 29%), and had a greater percentage of neonatal intensive care unit admissions (59% vs 21%), a greater percentage of birth weight <1500 g, and a greater frequency of respiratory distress syndrome (16% vs 2%) than nonreduced twins. There was no difference in neonatal survival and neurologic morbidity when all groups were compared. CONCLUSION: Although early delivery and prolonged (maternal and neonatal) hospitalization were common with quadruplets and triplets, maternal and neonatal outcomes were excellent. The decision for reduction from triplets to twins may not necessarily change pregnancy outcome but should still be discussed as an option for the parents. Continued efforts need to be made to reduce the overall number of iatrogenic high-order multiple gestations.     

Perinatal mortality and morbidity rates among singleton,twin, and triplet gestations

Objective: To determine rates of perinatal mortality and morbidity from 24 to 43 weeks gestation among singletons, twins, and triplets.Methods: Successfully linked data from 1992 Californian maternal and infant discharge records as well as birth and death certificates from acute care civilian hospitals were examined for perinatal mortality and morbidity. Perinatal mortality was defined as the sum of all stillbirths and neonatal deaths. Deliveries from 24 to 43 weeks gestation among singleton, twin, and triplet pregnancies were collected as separate data sets. Perinatal mortality was identified using birth certificate death indicators excluding deaths caused by congenital anomalies. Neonatal deaths were identified from death indicators found in the death certificates. For the purpose of this study, perinatal morbidities were identified by ICD-9 codes and limited to respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), and necrotizing enterocolitis (NEC). Perinatal mortality and morbidity rates were expressed as a percent of live births stratified by gestational age. Perinatal mortality data were expressed in log scale and perinatal morbidity rates were statistically compared.Results: There were 571,390 total births in California of which 527,677 (92%) were singleton, 12,535 (2%) were twin, and 367 (0.06%) were triplet gestations. Across gestation, the rate of RDS between triplets and twins was comparable (6.6% vs 6.8%). However, the rates of IVH and NEC were significantly greater in triplets than in twins (20% vs 8%, P < .0001, and 25% vs 9%, P < .0001, respectively). The perinatal mortality rates are shown below.

1. Download : Download full-size image

Conclusions: Perinatal mortality rates were comparable among singleton, twin, and triplet gestations delivered between 24 and 30 weeks gestation. Unlike singletons and twins, the triplet perinatal mortality rate did not fall between 31 and 36 weeks gestation and remained at 2.6%. Twin perinatal mortality rate was equivalent to singletons until 36 weeks gestation. IVH and NEC were significantly greater among triplets regardless of gestational age. These data suggest that antepartum fetal surveillance of triplet pregnancies should start as early as 30 weeks gestation while testing for twin pregnancies can begin at 36 weeks gestation.     

Differences in TDx fetal lung maturity assay values between twin and singleton gestations

OBJECTIVE: The purpose of this study was to quantify differences in indexes of pulmonary maturity between singleton and twin gestations by means of the TDx fetal lung maturity assay.Study Design: We identified records of a total of 830 singleton and twin pregnancies not complicated by diabetes and delivered between 28 and 37 weeks' gestation from December 1994 through August 1995. Among these, 170 (20%) had TDx fetal lung maturity measurements performed within 72 hours of delivery. Linear regression was used to assess differences in TDx fetal lung maturity assay values between singleton gestations (n = 143 gestations) and twin gestations (n = 27 gestations) while controlling for potential confounding factors. RESULTS: Twin gestations were no more likely than singleton gestations to undergo TDx fetal lung maturity screening (odds ratio, 1.3; 95% confidence interval, 0.8-2.2). Pregnancy complications and corticosteroid treatment were similar in the two groups. After 31 weeks' gestation the twin gestations had significantly higher TDx fetal lung maturity values. Linear regression with controls for gestational age indicated that twin gestations on average had a TDx fetal lung maturity value that was 22.0 mg/g (95% confidence interval, 9.8-34.6 mg/g) higher than that of gestational age-matched singleton gestations. CONCLUSION: Beyond 31 weeks' gestation twin pregnancies appeared to have a TDx fetal lung maturity value that was 22 mg/g higher than that of singleton pregnancies. If the underlying incidences of respiratory distress syndrome are similar between twin and singleton gestations, then the potential exists for false-positive prediction of adequate lung maturity values among twin gestations.     

Nonstress test assessment of twins.

Twin pregnancies have higher perinatal morbidity and mortality rates than singleton pregnancies. Researchers have demonstrated that one major benefit of prenatal care in the twin gestation is reduced fetal death rate. This study to determine the relationship of nonstress tests (NSTs) to pregnancy outcome in twin gestations comprised 665 women who delivered at Los Angeles County-University of Southern California Women's Hospital from January 1985 to January 1989. These patients, all of whom had prenatal care (PNC), were subdivided into two groups: (1) PNC and NSTs and (2) PNC and no NSTs. The groups did not differ statistically with regard to gravidity, parity and abortions. NSTs were selectively done on twin gestations complicated by discordancy or other fetal/maternal complications. Ten pregnancies were complicated by fetal demise of one or both twins in patients who received prenatal care without NSTs. Among the NST group there was one fetal demise. Although the NST group had fewer fetal deaths, the reduction was not statistically significant (P = .062). Infant birth weight was identified as a confounder because the NST group had a statistically higher mean birth weight. Definitive proof of the ability of NSTs to reduce the fetal death rate in twin gestations complicated by discordancy or other pregnancy complications awaits a large, prospective, randomized trial.     

Preterm birth unrelated to maternal height in Asian women with singleton gestations.

OBJECTIVE: To determine whether maternal height has a significant effect on the length of gestation or the incidence of preterm birth in Asian women with singleton gestations. METHODS: We retrospectively studied a cohort of consecutive adult Asian women with singleton gestations who delivered in a 2-year period, to determine the relationship between maternal height, expressed in quartiles, and the mean gestational age and incidence of preterm birth. RESULTS: Of the 9819 deliveries during that period, 449 were excluded from analysis because of multiple gestation, maternal age less than 20 years, or incomplete data because of no antenatal care in our hospital. The 25th, 50th, and 75th percentile values of maternal height were 152, 156, and 160 cm, respectively. Significant differences were found in the maternal age, weight and body mass index (BMI), birth weight, and birth weight as a percentage of maternal weight, among the four quartiles, but the trend for age, BMI, and birth weight percentage was opposite to that of maternal weight and birth weight. However, there was no significant difference in the mean gestational age or incidence of preterm birth at less than 28, 28-31, or 32-36 weeks' gestation. There was no difference in the incidence of pregnancies beyond 41 weeks' gestation. CONCLUSION: Maternal stature does not have a significant influence on the mean gestational age or incidence of preterm birth in adult Asian women with singleton gestations.     

Maternal plasma adenosine and endothelin-1 levels in twin gestation complicated by preeclampsia

The aim of this study was to evaluate the relationship between the vascular resistance in uterine arteries and the maternal release of adenosine and endothelin-1 in twin gestations with and without preeclampsia. Uterine artery Doppler velocimetry and maternal arterial blood sampling were performed in 14 women with normal singleton gestation, nine women with singleton gestation with preeclampsia, eight women with dichorionic twin gestation without preeclampsia and six women with dichorionic twin gestation with preeclampsia at 28–34 weeks’ gestation. In normal singleton gestations, the average maternal uterine arteries pulsatility index (PI), plasma adenosine and endothelin-1 levels were 0.64±0.07, 0.34±0.11 μmol/l and 1.29±0.31 pg/ml, respectively. In preeclamptic singleton gestations, increased vascular resistance in the uterine arteries (PI: 0.85±0.14, P<0.05) and the elevation of maternal arterial plasma adenosine (0.48±0.14 μmol/l, P<0.05) and endothelin-1 levels (1.91±0.55 pg/ml, P<0.05) were observed. In the normal twin gestation group, the average maternal vascular resistance of the uterine arteries (PI: 0.55±0.09) was lower than that in the normal singleton gestation group, while the average plasma adenosine levels (0.47±0.12 μmol/l) were higher than that in normal singleton gestation. On the other hand, significant increased plasma endothelin-1 concentrations (1.87±0.42 pg/ml) were observed in the preeclamptic twin gestation groups without changes in plasma adenosine levels or vascular resistance of uterine arteries. Our results indicate the presence of different mechanisms for the pathogenesis of preeclampsia between twin and singleton gestations. Received: 5 October 2001 / Accepted: 3 December 2001 Correspondence to S. Suzuki