Obstetric and neonatal risk of pregnancies after assisted reproductive technology: a matched control study

BACKGROUND: The aim of the study was to evaluate the obstetric and neonatal outcome of pregnancies after assisted reproduction technology (ART) in comparison with matched controls from spontaneous pregnancies. METHODS: A total of 12 920 deliveries at the Department of Obstetrics and Gynecology, University of Szeged, from 1 January 1995 to 31 December 2001 were subjected to retrospective analysis. Two hundred and eighty-four singleton, 75 twin and 17 triplet pregnancies after ovulation induction (n = 114; 30.3%), intrauterine insemination (n = 33; 8.8%) and in vitro fertilization (n = 229; 60.9%) were evaluated. The pregnancy outcome of the singleton and twin pregnancies was compared with that for controls matched with regard to age, gravidity and parity and previous obstetric outcome after spontaneous pregnancies. RESULTS: Twenty-four percent of the assisted reproductive pregnancies were multiple pregnancies. The incidences of singleton intrauterine growth retardation (IUGR) and preterm birth were reasonably similar to those among the controls (IUGR: 6.3% vs. 4.2%; preterm births: 13.0% vs. 9.9%, for the cases and the controls, respectively). As compared with the controls, there was an increased incidence of cesarean section among the singleton (41.2% vs. 34.5%, p = 0.12; OR 1.33; 95% CI 0.95-1.87) and twin assisted reproduction pregnancies (66.7% vs. 60.0%), but without significant differences. CONCLUSIONS: Increased obstetric risk could be observed concerning threatened preterm delivery and cesarean section rate in the study group. The perinatal outcome of singleton and twin pregnancies following assisted reproductive techniques is comparable with that of spontaneously conceived, matched pregnancies.     

Recurrence of preterm birth in singleton and twin pregnancies

OBJECTIVE: To assess recurrence of preterm birth and its impact on an obstetric population. METHODS: Women with consecutive births at our hospital beginning with their first pregnancy were identified (n = 15,945). The first pregnancy was categorized as delivered between 24 and 34 weeks' gestation or 35 weeks or beyond, singleton or twin, and spontaneous or induced. The risk of preterm delivery in these same women during subsequent pregnancies was then analyzed. RESULTS: Compared with women who delivered a singleton at or beyond 35 weeks' gestation in their first pregnancy, those who delivered a singleton before 35 weeks were at a significant increased risk for recurrence (odds ratio [OR] 5.6, 95% confidence interval [CI] 4.5, 7.0), whereas those who delivered twins were not (OR 1.9, 95% CI 0.46, 8.14). The OR for recurrent spontaneous preterm birth presenting with intact membranes was 7.9 (95% CI 5.6, 11.3) compared with 5.5 (95% CI 3.2, 9.4) with ruptured membranes. Of those women with a recurrent preterm birth, 49% delivered within 1 week of the gestational age of their first delivery and 70% delivered within 2 weeks. Among 15,863 nulliparous women with singleton births at their first delivery, a history of preterm birth in that pregnancy could predict only 10% of the preterm births that ultimately occurred in the entire obstetric population. CONCLUSION: In a population-based study at our hospital, women who initially delivered preterm and thus were identified to be at risk for recurrence ultimately accounted for only 10% of the prematurity problem in the cohort.     

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.     

Recurrence of preterm birth in twin pregnancies in the presence of a prior singleton preterm birth

OBJECTIVE: We examined recurrence of preterm birth in twin pregnancy in the presence of a previous singleton preterm pregnancy, and assessed if these recurrence risks differed for medically indicated and spontaneous preterm birth. METHODS: A retrospective cohort study was designed using the maternally-linked data of women who delivered a first singleton live birth followed by a twin birth in the second pregnancy (n = 2329) in Missouri (1989--97). We examined preterm birth recurrence at <37 in the second twin pregnancy among women with a prior singleton preterm birth. Recurrence risks were based on hazard ratios (HR) and 95% confidence intervals (CI) estimated from Cox proportional hazards models after adjusting for potential confounders. RESULTS: Preterm birth rates in the second twin pregnancy were 69.0% and 49.9% among women who had a previous preterm and term singleton birth, respectively (HR 1.8, 95% CI 1.6-2.1). The preterm birth rate in the second pregnancy was about 95% when the first singleton pregnancy ended at <30 weeks. Women delivering preterm following a medical intervention in the first pregnancy had increased recurrence for both spontaneous (HR 1.4, 95% CI 1.1-2.0) and indicated (HR 2.4, 95% CI 1.8-3.2) preterm birth; similarly among women with a prior spontaneous preterm birth, hazard ratios were 1.8 (95% CI 1.5-2.1) and 1.6 (95% CI 1.3-1.9), for spontaneous and indicated preterm birth in the second twin pregnancy, respectively. CONCLUSIONS: Women with a singleton preterm birth carry increased risk of preterm birth in the subsequent twin pregnancy. A history of a singleton preterm birth has an independent and additive contribution to risk of preterm birth in the subsequent twin gestation.     

Maternal risks and perinatal outcome in a Danish national cohort of 1005 twin pregnancies: the role of in vitro fertilization

BACKGROUND: Twin pregnancies constitute 25% of all in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) pregnancies. There is a lack of knowledge on maternal risks and perinatal outcome of IVF/ICSI twin pregnancies. METHODS: National survey by questionnaire (n = 1769). The study population consisted of all IVF/ICSI twin mothers (n = 266) and the two control groups of all IVF/ICSI singleton mothers (n = 764) and non-IVF/ICSI twin mothers (n = 739) who delivered in Denmark in 1997. The response rate was 89% among IVF twin mothers and overall 81%. RESULTS: In terms of maternal risks and perinatal outcome no significant differences were observed between IVF/ICSI twin and non-IVF/ICSI twin pregnancies after stratification for maternal age and parity. Nevertheless, IVF/ICSI twin mothers were more frequently on sick leave (OR 2.5, 95% CI 1.5-4.0) and hospitalized (OR 1.9, 95% CI 1.3-2.8) during pregnancy. Compared with IVF/ICSI singleton pregnancies, IVF/ICSI twin pregnancies were characterized by a higher incidence of preeclampsia (OR 2.4, 95% CI 1.5-4.2) and a higher frequency of sick leave (OR 6.8, 95% CI 4.4-10.5) and hospitalizations during pregnancy (OR 3.5, (95% CI 2.5-4.9); moreover, mean birthweight (p < 0.001) and gestational age (p < 0.001) were lower. No differences were observed in the incidence of pregnancy-induced hypertension and gestational diabetes between IVF/ICSI twin and singleton pregnancies. CONCLUSION: Although this population study indicates that maternal risks in IVF/ICSI twin pregnancies are comparable with non-IVF/ICSI twin pregnancies, the IVF/ICSI twin mothers were more likely to be on sick leave or hospitalized during pregnancy. Furthermore, maternal risks were higher and obstetric outcome poorer in IVF/ICSI twin vs. IVF/ICSI singleton pregnancies.     

Obstetric outcome of twin pregnancies conceived by in vitro fertilization and ovulation induction compared with those conceived spontaneously

OBJECTIVE: To compare the obstetric characteristics of twin pregnancies conceived by in vitro fertilization (IVF) and ovulation induction with those conceived spontaneously. DESIGN: Case control study. SETTING: Tertiary Medical Center. PATIENTS: All twin deliveries that were achieved by IVF (n=558) and ovulation induction (n=478) from January 1988 through December 2002 were evaluated. Each group was compared with a control group that conceived spontaneously (n=3694) and was delivered during the same period. INTERVENTIONS: Ovulation induction, IVF-ET. MAIN OUTCOME MEASURES: Obstetrical complications. RESULTS: Multivariate analysis showed that patients who conceived with the assistance of IVF and ovulation induction had a significantly higher risk for gestational diabetes mellitus (odds ratio [OR]=2.41, 95% confidence interval [CI]=1.77-3.29 and OR=1.71, CI=1.2-2.42, respectively), cesarean section (OR=2.17, 95% CI=1.74-2.70 and OR=1.76, CI=1.43-2.16, respectively), and a lower gestational age at birth in the IVF group (OR=0.91, 95% CI=0.88-0.94), compared with their controls. CONCLUSIONS: After controlling for maternal age, and nulliparity we demonstrated that twin pregnancies conceived with the assistance of IVF and ovulation induction are at increased risk for gestational diabetes mellitus, and delivery by cesarean section. In addition, IVF conceived pregnancies have a lower gestational age at birth.     

足月择期剖宫产的时机与新生儿结局分析

目的 比较不同孕周行足月择期剖宫产的新生儿结局.方法 自2002年9月至2009年11月根据北京协和医院产科电子数据库系统登记的所有中国人群的孕产妇资料中,选择妊娠满37周后在临产前没有明确妇产科和内科合并症的宫内单胎活产儿的孕妇施行择期剖宫产的病历资料,采用单因素方差分析母亲的一般情况,采用趋势检验方法比较不同孕周组的新生儿不良事件的发生情况,包括新生儿死亡、呼吸系统疾病(呼吸窘迫综合征或短暂的窒息)、感染(包括败血症)、转入新生儿重症监护病房、在新生儿重症监护病房住院＞5 d等.结果 共4565例初次和409例再次足月择期剖宫产病例纳入分析.妊娠39周前行手术者和妊娠39～39+6周中初次剖宫产者占所有足月初次择期剖宫产总数的比例分别为48.1%(2194/4565)和40.0%(1828/4565).再次择期剖宫产者中妊娠39周前和妊娠39～39+6周手术者的比例分别为67.2%(275/409)和29.3%(120/409).未发生围产期胎儿或新生儿死亡.与妊娠39～39+6周相比,妊娠37～37+6周和38～38+6周行择期剖宫产均可能增加新生儿不良事件的发生风险:初次剖宫产,妊娠37～37+6周OR=1.4(95% CI:0.9～2.0),38～38+6周OR=1.1(95%CI:0.9～1.4);再次剖宫产,37～37+6周OR=2.5(95% CI:1.1～5.8),38～38+6周OR=1.3(95%CI:0.6～2.7).结论 我院妊娠39周前的择期剖宫产比例较高,但可能增加新生儿呼吸系统疾病等不良事件的发生风险.建议将妊娠39～39+6周作为择期剖宫产的时机以减少新生儿呼吸系统等不良时间的发生风险.

Abstract：

Objective To compare the neonatal outcomes of different gestational age at which elective cesarean sections at term were performed. Methods All the cases of cesarean section registered in Peking Union Medical College Hospital from September 2002 to November 2009 were collected. Women with viable singleton pregnancies delivered before the onset of labor and without recognized indications for cesarean section after 37 weeks at term were included and their general information and outcomes were compared with one-way ANOVA. All the maternal data and neonatal adverse events were compared with Cochran-Armitage test among different gestational weeks, including respiratory complications (respiratory distress syndrome or transient tachypnea of the newborn), infections, admission to the neonatal intensive care unit (NICU), and hospitalization in NICU＞5 d. Results Of 8122 primary cesarean sections and 594 repeat cesarean sections at term, 4565 and 409 cases were performed electively as the primary or repeat cesarean section. Among the 4565 women underwent primary elective cesarean sections, 2194 (48.1%) were before 39 gestational weeks,and 1828 (40.0%) at 39-39+6 weeks. While, among the 409 repeat elective cesareans sections, these figures were 275 (67.2%) and 120 (29.3%), respectively. No fetal or neonatal death occurred during perinatal period. Compared with births at 39-39+6 weeks, births at 37-37+6 weeks or 38-38+6 weeks were associated with increased risk of the neonatal adverse events. For the primary cesarean section cases, the odds ratio (OR) for births at 37-37+6 weeks and 38-38+6 weeks was 1.4 (95% CI: 0.9-2.0) and 1.1 (95% CI: 0.9-1.4), respectively. For the repeat cesarean section cases, OR for births at 37-37+6 weeks and 38-38+6 weeks was 2.5 (95% CI: 1.1-5.8) and 1.3 (95% CI: 0.6-2.7) respectively. Conclusions Elective cesarean section before 39 weeks of gestation is popular and associated with adverse neonatal outcomes. Elective cesarean section performed after 39-39+6 gestational weeks might decrease the risk of adverse neonatal outcomes.     

Non-medical factors affecting antenatal preferences for delivery route and actual delivery mode of women in southwestern Iran

Objective: Assessment of the contribution of non-medical factors to mode of delivery and birth preference in Iranian pregnant women in southwestern Iran.

Study design: This cohort study used data from a structured questionnaire completed in early pregnancy and information about the subsequent delivery obtained through personal contact. Women were recruited by random sampling from antenatal clinics when scheduling visits over the course of 5 weeks from December 2012 to February 2013 and were followed-up 1 month after birth. Of the 2199 women recruited, 99.63% were eligible for the study.

Results: Of the 748 women who expressed a desire to deliver their babies by cesarean section (CS) in early pregnancy, 87% had an elective cesarean section. The logistic regression analyses showed that normative beliefs (odds ratio [OR] 1.792, 95% confidence interval (1) 1.073–2.993), control beliefs (OR: 0.272, 95% CI: 0.162–0.459), and evaluation of outcomes (OR: 0.431, 95% CI: 0.268–0.692) favored the preference for cesarean section. The desire for delivery by elective cesarean section was associated with normative beliefs (OR: 1.138; 95% CI: 1.001–1.294), control beliefs (OR: 0.804; 95% CI: 0.698–0.927), and expectations about maternity care (OR: 0.772; 95% CI: 0.683–0.873), medical influences (OR: 1.150; 95% CI: 1.023–1.291), evaluation of outcome (OR: 0.789; 95% CI: 0.696–0.894), age, preference for cesarean section (OR: 5.445; 95% CI: 3.928–7.546), spouse educational level, and number of live births.

Conclusions: A woman’s preference for delivery by cesarean section influenced their subsequent mode of delivery. Asking women in early pregnancy about their preferred mode of delivery provides the opportunity to extend their supports which might reduce the rate of elective cesarean section. This decision is affected by age, spouse educational level, number of live births, and preconceived maternal attitudes about delivery.     

Risk of cesarean delivery with elective induction of labor at term in nulliparous women.

OBJECTIVE: To quantify the risk of cesarean delivery associated with elective induction of labor in nulliparous women at term. METHODS: We performed a cohort study on a major urban obstetric service that serves predominantly private obstetric practices. All term, nulliparous women with vertex, singleton gestations who labored during an 8-month period (n = 1561) were divided into three groups: spontaneous labor, elective induction, and medical induction. The risk of cesarean delivery in the induction groups was determined using stepwise logistic regression to control for potential confounding factors. RESULTS: Women experiencing spontaneous labor had a 7.8% cesarean delivery rate, whereas women undergoing elective labor induction had a 17.5% cesarean delivery rate (adjusted odds ratio [OR] 1.89; 95% confidence interval [CI] 1.12, 3.18) and women undergoing medically indicated labor induction had a 17.7% cesarean delivery rate (OR 1.69; 95% CI 1.13, 2.54). Other variables that remained significant risk factors for cesarean delivery in the model included: epidural placement at less than 4 cm dilatation (OR 4.66; 95% CI 2.25, 9.66), epidural placement after 4 cm dilatation (OR 2.18; 95% CI 1.06, 4.48), chorioamnionitis (OR 4.61; 95% CI 2.89, 7.35), birth weight greater than 4000 g (OR 2.59; 95% CI 1.69, 3.97), maternal body mass index greater than 26 kg/m2 (OR 2.36; 95% CI 1.61, 3.47), Asian race (OR 2.35; 95% CI 1.04, 5.34), and magnesium sulfate use (OR 2.18; 95% CI 1.04, 4.55). CONCLUSION: Elective induction of labor is associated with a significantly increased risk of cesarean delivery in nulliparous women. Avoiding labor induction in settings of unproved benefit may aid efforts to reduce the primary cesarean delivery rate.     

Primiparity, assisted reproduction, and preterm birth in twin pregnancies: a population based study

Objective To determine the prevalence of pregnancy complications among primiparous patients with twin gestation in our population and to investigate the association between the increased rates of assisted reproduction (ART) in twin gestation and preterm birth (PTD). Material and methods A retrospective population based cohort study was designed, including all twin deliveries after 24 weeks gestation (n = 2,601). The study group included 666 primiparous women and the comparison group 1,935 multiparous women. Maternal characteristics and perinatal outcome were evaluated. Women with fetal malformations were excluded. A multiple logistic regressions analysis for independent risk factors was performed including factors that were significantly different between the study groups in the univariate analysis. Patient’s data were obtained from computerized database and analyzed using SPSS statistical package. Results Primiparous women had a significantly higher rate of preeclampsia, chronic hypertension, ART, prelabor rupture of membranes (PROM) preterm deliveries (PTD), labor dystocia, cesarean section (CS) and vacuum extraction of the first twin than the multiparous group. Primiparous patients had a significantly lower gestational age at delivery and neonatal birth weight of the first and second twin. In multiple logistic regressions analysis primiparity and ART were independent risk factors for PTD, (OR 1.45, 95% CI 1.18–1.78; OR 1.36, 95% CI 1.09–1.71, respectively). Conclusions (1) Primiparous patients with twin gestation represent a unique population with high rate of infertility and underlying diseases such as chronic hypertension in comparison to the multiparous women with twin gestation; (2) primiparity is an independent risk factor for prematurity in twin gestations; and (3) although primiparous women had an increased maternal complications, neonatal mortality rates were not significantly different from multiparous women.     

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.     

Term induction of labor and risk of cesarean delivery by parity

Abstract

Objective: To evaluate the risk of cesarean delivery among both nulliparous and multiparous women undergoing a term induction of labor compared to women that present in spontaneous labor at term.

Methods: We performed a retrospective cohort study of term (≥37 weeks) singleton pregnancies between 2005 and 2010 comparing women that had an induction to those that presented in spontaneous labor. Multiparity was defined as a prior delivery after 20 weeks’ gestation. Chi-square was used to compare categorical variables. Multivariable logistic regression was used to control for confounders. Analyses were stratified by parity.

Results: 863 women were included in the analysis. There were 605 inductions (cesarean rate 23%) and 257 spontaneous labor (cesarean rate 7%), OR 3.4, 95% CI [2.1–5.4]. Stratified by parity, nulliparas undergoing induction had an increased cesarean rate compared to spontaneous labor (27% versus 11%, OR 3.13, 95% CI [1.76–5.57]) as did multiparas (13% versus 3%, OR 4.04, 95% CI [1.36–11.94]). This increased risk for cesarean after induction remained in both nulliparous and multiparous women even after controlling for confounders (aOR 2.90, 95% CI [1.60–5.25] and aOR 3.47, 95% CI [1.12–10.67], respectively). Neither starting cervical exam nor indication for induction altered this increased risk.

Conclusions: The increased risk of cesarean in women undergoing an induction is present regardless of parity and indication for induction. This should be taken into account when counseling women regarding risks of induction, regardless of parity. Future studies should focus on other clinical characteristics of induction that may mitigate this risk.     

Obstetric and perinatal outcome of 1655 ICSI and 3974 IVF singleton and 1102 ICSI and 2901 IVF twin births: a comparative analysis

A total of 3974 IVF and 1655 ICSI singleton births and 2901 IVF and 1102 ICSI twin births were evaluated. Pregnancies after both fresh and frozen transfers were included. IVF and ICSI singleton pregnancies were very similar for most obstetric and perinatal variables. The only significant difference was a higher risk for prematurity (< 37 weeks of amenorrhoea) in IVF pregnancies compared with ICSI pregnancies (12.4 versus 9.2%, OR = 1.39, 95% CI = 1.15-1.70). For twin pregnancies, differences were not statistically different except for a higher incidence of stillbirths in the ICSI group (2.08 versus 1.03%, OR = 2.04, 95% CI = 1.14-3.64). Intrauterine growth retardation with or without pregnancy-induced hypertension was observed more often in the ICSI group. Regression analysis of the data with correction for parity and female age showed similar results for twins. For singletons, this analysis showed similar results with the exception of low birth weight babies (< 2500 g), which were also observed more often in IVF pregnancies (9.6 versus 7.9%, OR = 0.79, CI = 0.65-0.98, P = 0.03). This large case-comparative retrospective analysis showed that the obstetric outcome and perinatal health of IVF and ICSI pregnancies is comparable.     

Cesarean delivery and postpartum mortality among primiparas in Washington State, 1987-1996(1)

OBJECTIVE: To examine the association between delivery method and mortality within 6 months of delivery among primiparas. METHODS: We conducted a population-based, retrospective cohort analysis using statewide, maternally linked birth certificate, hospital discharge, and death certificate data. The present cohort was all primiparas who gave birth to live-born infants in civilian hospitals in Washington State from January 1, 1987 through December 31, 1996 (n = 265,471). Odd ratios (OR) and 95% confidence intervals (CI) were calculated for overall mortality, pregnancy-related mortality, and pregnancy-unrelated mortality associated with delivery method. RESULTS: Thirty-two women (12.1 per 100,000 singleton live births) died within 6 months of delivery of their first child. Eleven of 32 deaths were pregnancy related (4.1 per 100,000 singleton live births, 95% CI 1.6, 6.5), and 21 of the 32 deaths were not pregnancy related (7.9 per 100,000 singleton live births, 95% CI 4.5, 11.3). The pregnancy-related mortality rate was higher among women delivered by cesarean (10.3/100,000) than among women delivered vaginally (2.4/100,000). In logistic regression analyses, women who had cesarean delivery were not at significantly higher risk of death overall after adjustment for maternal age (OR 1.7, 95% CI 0.3, 3.6), pregnancy-related death after adjustment for maternal age and severe preeclampsia (OR 2.2, 95% CI 0.6, 7.9), or pregnancy-unrelated death after adjustment for maternal age and marital status (OR 0.9, 95% CI 0.3, 2.7), relative to women who had vaginal delivery. CONCLUSION: Cesarean delivery might be a marker for serious preexisting morbidities associated with increased mortality risk rather than a risk factor for death in and of itself. Data from additional sources such as medical records and autopsy reports are necessary to disentangle preexisting mortality risk from risk associated solely with delivery method.     

Admission of Term Infants to Neonatal Intensive Care: A Population‐Based Study

ABSTRACT: Background: Neonatal intensive care and special care nurseries provide a level of care that is both high in cost and low in volume. The aim of our study was to determine the rate of admission of term babies to neonatal intensive care in association with each method of giving birth among low‐risk women. Methods: We examined the records of 1,001,249 women who gave birth in Australia during 1999 to 2002 using data from the National Perinatal Data Collection. Among low‐risk women, we calculated the adjusted odds of admission to neonatal intensive care at term separated for each week of gestational age between 37 and 41 completed weeks. We also calculated the odds of admission to neonatal intensive care in association with cesarean section before or after the onset of labor, and vacuum or instrumental birth compared with unassisted vaginal birth at 40 weeks’ gestation. Results: The overall rate of admission to neonatal intensive care of term babies was 8.9 percent for primiparas and 6.3 percent for multiparas. After a cesarean section before the onset of labor, the adjusted odds of admission among low‐risk primiparas at 37 weeks’ gestation were 12.08 (99% CI 8.64–16.89); at 38 weeks, 7.49 (99% CI 5.54–10.11); and at 39 weeks, 2.80 (99% CI 2.02–3.88). At 41 weeks, the adjusted odds were not significantly higher than those at 40 weeks’ gestation. Among low‐risk multiparas who had a cesarean section before the onset of labor, the adjusted odds of admission to neonatal intensive care at 37 weeks’ gestation were 15.40 (99% CI 12.87–18.43); at 38 weeks, 12.13 (99% CI 10.37–14.19); and at 39 weeks, 5.09 (99% CI 4.31–6.00). At 41 weeks’ gestation, the adjusted odds of admission were significantly lower than those at 40 weeks (AOR 0.64, 99% CI 0.47–0.88). Babies born after any operative method of birth were at increased odds of being admitted to neonatal intensive care compared with those born after unassisted vaginal birth at 40 weeks’ gestation. Conclusions: The adjusted odds of admission to neonatal intensive care for babies of low‐risk women were increased after birth at 37 weeks’ gestation. In a climate of rising cesarean sections, this information is important to women who may be considering elective procedures. (BIRTH 34:4 December 2007)     

Mode of Delivery after Epidural Analgesia in a Cohort of Low‐Risk Nulliparas

Abstract: Background: Although epidural analgesia is widespread and very effective for alleviating labor pain, its use is still controversial, as the literature is inconsistent about the risk of adverse birth outcome after administration of epidural analgesia. The aim of this study was to explore associations between epidural analgesia and mode of delivery. Methods: Data were obtained from a prospective cohort from nine Danish labor wards and comprised 2,721 term nulliparous women with spontaneous onset of labor and a singleton fetus in cephalic presentation. Information about epidural analgesia, mode of delivery, and birth complications was obtained by the staff attending labor. Additional information was provided from self‐administered questionnaires in gestational week 37. Multiple logistic regression analyses were used to estimate the association between epidural analgesia and birth outcomes. Results are presented as crude and adjusted odds ratios (OR [95% CI]). Results: Of the total cohort, 21.6 percent required epidural analgesia, 8.7 percent had emergency cesarean section, and 14.9 percent had vacuum extraction. Women with epidural analgesia had a higher risk of emergency cesarean section (adjusted OR: 5.8; 95% CI: 4.1–8.1), and vacuum extraction (adjusted OR: 1.7; 95% CI: 1.3–2.2). In a subgroup of the cohort with a very low overall risk of cesarean section, 3.4 percent had emergency cesarean section and an increased risk of emergency cesarean section was also found in this group (adjusted OR: 3.5; 95% CI: 1.5–8.2). Conclusions: In nulliparous women of a very low‐risk population, use of epidural analgesia for labor pain was associated with higher risks of emergency cesarean section and vacuum extraction. (BIRTH 38:4 December 2011)     

Does size matter? A population-based study of birth in lower volume maternity hospitals for low risk women

OBJECTIVE: To study the association between volume of hospital births per annum and birth outcome for low risk women. DESIGN: Population-based study using the National Perinatal Data Collection (NPDC). SETTING: Australia. PARTICIPANTS: Of 750,491 women who gave birth during 1999-2001, there were 331,147 (47.14%) medically 'low risk' including 132,696 (40.07%) primiparae and 198,451 (59.93%) multiparae. METHODS: The frequency of each birth and infant outcome was described according to the size of the hospital where birth took place. We investigated whether unit size (defined by volume) was an independent risk factor for each outcome factor using public hospitals with greater than 2000 births per annum as a reference point. MAIN OUTCOME MEASURES: Rates of intervention at birth and neonatal mortality for low risk women in relation to hospitals with <100, 100-500, 501-1000, 1001-2000 and >2001 births per annum. RESULTS: Neonatal death was less likely in hospitals with less than 2000 births per annum regardless of parity. For multiparous low risk women in hospitals of 100 and 500 births per annum compared with hospitals of >2000 births per annum the adjusted odds of neonatal mortality [adjusted odds ratio (AOR) 0.36; 99% confidence interval (CI) 0.14-0.93]. For low risk primiparous women in hospitals with less than 100 births per annum, there were lower rates of induction of labour (AOR 0.62; 99% CI 0.54-0.73); intrathecal analgesia/anaesthesia (AOR 0.34; 99% CI 0.28-0.42); instrumental birth (AOR 0.80; 99% CI 0.69-0.93); caesarean section after labour (AOR 0.59; 99% CI 0.49-0.72) and admission to a neonatal unit (AOR 0.15; 99% CI 0.10-0.22) and for low risk multiparous women in hospitals with less than 100 births per annum: induction (AOR 0.69; 99% CI 0.62-0.76); intrathecal analgesia/anaesthesia (AOR 0.32; 99% CI 0.29-0.36); instrumental birth (AOR 0.52; 99% CI 0.41-0.67); caesarean section after labour (AOR 0.41; 99% CI 0.33-0.52); and admission to a neonatal unit (AOR 0.09; 99% CI 0.07-0.12). CONCLUSIONS: In Australia, lower hospital volume is not associated with adverse outcomes for low risk women.     

Ethnic disparity in the success of vaginal birth after cesarean delivery.

OBJECTIVE: To estimate whether maternal race/ethnicity is independently associated with successful vaginal birth after cesarean delivery (VBAC). STUDY DESIGN: A retrospective cohort study from January 1, 1997 to July 30, 2002 of women with singleton pregnancies and a previous cesarean delivery. The odds ratio (OR) for successful VBAC as a function of ethnicity was corrected for age >35 years, parity, weight gain, diabetes mellitus, hospital site, prenatal care provider, gestational age, induction, labor augmentation, epidural analgesia, and birth weight >4000 g. RESULTS: Among 54 146 births, 8030 (14.8%) occurred in women with previous cesarean deliveries. The trials of labor rates were similar among Caucasian (46.6%), Hispanic (45.4%), and African American (46.0%) women. However, there was a significant difference among ethnic groups for VBAC success rates (79.3% vs. 79.3% vs. 70.0%, respectively). When compared to Caucasian women, the adjusted OR for VBAC success was 0.37 (95% confidence interval (CI) 0.27-0.50) for African American women and 0.63 (95% CI 0.51-0.79) for Hispanic women. CONCLUSION: African American and Hispanic women are significantly less likely than Caucasian women to achieve successful VBAC.     

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.     

Obstetric outcomes in adolescent pregnancies: a racial/ethnic comparison

Abstract

Objective: To examine obstetric outcomes for adolescents among the major US racial/ethnic groups.

Methods: This is a retrospective cohort study of singleton births to nulliparous women aged 12 to 19 years from 1988 to 2008. The prevalence of preterm delivery, cesarean delivery, preeclampsia, gestational diabetes, low birth weight and low Apgar score were compared across African-American, Asian, Latina and White adolescents.

Results: 1865 adolescents were included in the analysis. Differences between racial/ethnic groups for rates of preterm delivery, cesarean delivery and gestational diabetes were statistically significant at p?<?0.05. African Americans had lower odds of preterm delivery (OR?=?0.58, 95% CI [0.38–0.90]) and gestational diabetes (OR?=?0.17, 95% CI [0.05–0.55]) than White adolescents. White adolescents had increased odds of cesarean delivery compared to African-American (OR?=?0.69, 95% CI [0.48–0.98]), Latina (OR?=?0.62, 95% CI [0.41–0.94]) and Asian adolescents (OR?=?0.41, 95% CI [0.25–0.68]). Although not statistically significant, White adolescents also had higher odds of low Apgar score. In the multivariate analysis, non-White adolescents continued to have improved outcomes, except in the case of low birth weight.

Conclusions: African-American, Asian and Latina adolescents may have similar or decreased risk of obstetric complications compared to White adolescents.