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 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.     

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.     

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)     

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.     

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.     

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.     

Increased incidence of obstetric and perinatal complications in pregnancies achieved using donor oocytes and single embryo transfer in young and healthy women. A prospective hospital-based matched cohort study

In this single-center matched-cohort study, women who underwent IVF/ICSI with donor oocytes between 2007 and 2014 (n?=?259) were compared to women undergoing autologous cycles during the same time period (n?=?515). The matching (1:2) took into consideration the women’s age, type of treatment (IVF/ICSI), and year of embryo transfer. All women were healthy and below 40?years of age at the time of IVF/ICSI, and the treatments were performed using a strict policy of single embryo transfer. Multiple logistic regression analysis, adjusted for body mass index (BMI), smoking, and parity, showed a four times increased risk of gestational hypertensive disorders (adjusted odds ratio, AOR 4.25; 95% confidence interval (CI), 2.61–6.92) and pre-eclampsia (AOR 3.99; 95% CI 2.27–7.00) in pregnancies achieved with donor oocytes. There was also a higher rate of cesarean section in women who gave birth after oocyte donation (AOR 1.69; 95% CI 1.22–2.35) and a higher risk of postpartum hemorrhage >1000?mL (AOR 1.59; 95% CI, 1.11–2.27). After further adjustment for preeclampsia in the logistic regression analysis, no additional increased perinatal risks were found. The incidence of preterm delivery, low weight at birth, need of neonatal intensive care, Apgar scores, and incidence of perinatal death were also similar between the groups.     

The effect of prepregnancy body mass index on birth weight,preterm birth,cesarean section,and preeclampsia in pregnant women

Objective: The objective of this study is to determine the impact of maternal prepregnancy BMI on birth weight, preterm birth, cesarean section, and preeclampsia among pregnant women delivering singleton life birth.

Methods: A cross-sectional study of 4397 women who gave singleton birth in Tehran, Iran from 6 to 21 July 2015, was conducted. Women were categorized into four groups: underweight (BMI?2), normal (BMI 18.5–25?kg/m²), overweight (BMI 25–30?kg/m²) and obese (BMI >30?kg/m²), and their obstetric and infant outcomes were analyzed using both univariate and multivariate logistic regression.

Results: Prepregnancy BMI of women classified 198 women as underweight (4.5%), 2293 normal (52.1%), 1434 overweight (32.6%), and 472 as obese (10.7%). In comparison with women of normal weight, women who were overweight or obese were at increased risk of preeclampsia (odds ratio (OR)?=?1.47, 95% CI?=?1.06–2.02; OR?=?3.67, 95% CI?=?2.57–5.24, respectively) and cesarean section (OR?=?1.21, 95% CI?=?1.04–1.41; OR?=?1.35, 95% CI?=?1.06–1.72, respectively). Infants of obese women were more likely to be macrosomic (OR?=?2.43, 95% CI?=?1.55–3.82).

Conclusion: Prepregnancy obesity is a risk factor for macrosomia, preeclampsia, and cesarean section and need for resuscitation.     

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.     

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.     

试管婴儿的出生缺陷及围产期情况研究

目的 探讨试管婴儿发生先天畸形、围产期合并症及死亡的危险性。方法 对1994年7月至2003年10月在我院接受IVF-ET术的156例母亲所生活产婴儿211例（试管婴儿组），及同期分娩的与母亲年龄及分娩时间相当的213例正常受孕母亲所生婴儿218例（对照组）进行分析，比较两组的母亲妊娠合并症及是否多胎、胎儿窘迫和出生窒息、出生缺陷、生后合并症、转儿科住院及存活情况。结果 试管婴儿组的多胎妊娠、早产及剖宫产率均显著高于对照组，分别为37．2％和2．3％，37．2％和8．5％、97．0％和71．8％（P均〈0．01）；妊高征、早期先兆流产率显著高于对照组，分别为22．4％和10．8％（P〈0．01），4．5％和0％（P〈0．01）；对照组胎儿窘迫的发生率显著高于试管婴儿组，14．6％和4．5％。试管婴儿组心脏畸形率和畸形总数皆高于对照组，但未显示出统计学差异。结论 试管婴儿的多胎率明显增高，由此造成的相关的围产期合并症发牛率也随之增高。