Gender does matter in perinatal medicine

OBJECTIVE: To investigate complications and outcome of pregnancies with male and female fetuses. METHODS: A population-based study comparing all singleton deliveries between the years 1988 and 1999 was performed. We compared pregnancies with male vs. female fetuses. Patients with a previous cesarean section (CS) were excluded from the study. Statistical analyses with the Mantel-Haenszel technique and multiple logistic regression models were performed to control for confounders. RESULTS: During the study period there were 55,891 deliveries of male and 53,104 deliveries of female neonates. Patients carrying male fetuses had higher rates of gestational diabetes mellitus (OR = 1.1; 95% CI 1.01-1.12; p = 0.012), fetal macrosomia (OR = 2.0; 95% CI 1.8-2.1; p < 0.001), failure to progress during the first and second stages of labor (OR = 1.2; 95% CI 1.1-1.3; p < 0.001 and OR = 1.4; 95% CI 1.3-1.5; p < 0.001, respectively), cord prolapse (OR = 1.3; 95% CI 1.1-1.6; p = 0.014), nuchal cord (OR = 1.2; 95% CI 1.1-1.2; p < 0.001) and true umbilical cord knots (OR = 1.5; 95% CI 1.3-1.7; p < 0.001). Higher rates of CS were found among male compared with female neonates (8.7 vs. 7.9%; OR = 1.1; 95% CI 1.06-1.16; p < 0.001). Using three multivariate logistic regression models and controlling for birth weight and gestational age, male gender was significantly associated with non-reassuring fetal heart rate patterns (OR = 1.5; 95% CI 1.4-1.6; p < 0.001), low Apgar scores at 5 min (OR = 1.5; 95% CI 1.3-1.8; p < 0.001) and CS (OR = 1.2; 95%CI 1.2-1.3; p < 0.001). Controlling for possible confounders like gestational diabetes, cord prolapse, failed induction, nonprogressive labor, fetal macrosomia, nuchal cord and true umbilical cord knots using the Mantel-Haenszel technique did not change the significant association between male gender and CS. CONCLUSION: Male gender is an independent risk factor for adverse pregnancy outcome.     

The clinical significance of bleeding during the second trimester of pregnancy

OBJECTIVE: This study aimed at investigating the clinical importance and pregnancy outcome in women suffering from bleeding during the second half of their pregnancies. METHODS: A population-based study including all deliveries between the years 1988 and 2005 was conducted. Comparison was performed between patients with and without vaginal bleeding during the second half of pregnancy. Pregnancies, which terminated before 22 weeks, multiple gestations and women lacking prenatal care were excluded from the analysis. Stratified analyses, using the Mantel-Haenszel technique, and a multiple logistic regression model were performed to control for confounders. RESULTS: During the study period, 175,093 singleton deliveries occurred in our institute. Of these, 2,010 (1.1%) were complicated with bleeding upon admission during the second half of pregnancy. The cases were mostly attributed to placental abruption (63.5%; n = 1,276) and placenta previa (36.5%; n = 734). Independent risk factors associated with bleeding, using a backward, stepwise multivariate analysis were oligohydramnios, polyhydramnions, [odds ratio (OR) = 1.6; 95% confidence interval (CI) 1.2-2.0; P = 001 and 1.5; 1.2-1.8; P < 0.01, respectively], suspected intra uterine growth restriction (IUGR, 3.2; 2.6-4.0; P < .001), gestational age, previous abortions and maternal age. These patients subsequently were more likely to deliver by cesarean section (CS, 72.9 vs. 12.1%, OR = 19.5; 95% CI 17.6-19.9; 14.9 vs. 1.1%; P < 0.001). Perinatal mortality among patients admitted due to second half bleeding was significantly higher as compared to patients without bleeding (P < .001). CONCLUSION: Bleeding upon admission during the second half of pregnancy is an independent risk factor for perinatal mortality. Careful surveillance, including fetal monitoring, is suggested in these cases in order to reduce the adverse perinatal outcome.     

Factors affecting the likelihood of successful induction after intravaginal misoprostol application for cervical ripening and labor induction

OBJECTIVE: Our purpose was to determine whether maternal age, height and weight, parity, duration of pregnancy, cervical dilatation or Bishop score, and birth weight could be used to predict the likelihood of successful induction in women given intravaginal misoprostol. STUDY DESIGN: A computerized database was compiled of 1373 pregnancies in which intravaginal misoprostol was given for cervical ripening and labor induction. Most of these women were placed on investigational protocols in which the dose of misoprostol administered was 25 to 50 microg and the dosing intervals ranged from 3 to 6 hours. No more than 24 hours of administration was permitted. Induction was undertaken in women with unfavorable cervical examinations (Bishop scores of 4 or less) and without spontaneous labor or ruptured membranes. Univariate and stepwise multiple regression analyses were performed to identify those factors associated with successful induction, defined as vaginal delivery within 24 hours of induction. RESULTS: Six hundred fifty-seven (48%) had successful induction. Parity (odds ratio [OR] 2.5, 95% CI 2.0-2.9, P <.0001), initial cervical dilatation (OR 1.9, 95% CI 1.6-2.3, P <.0001), Bishop score (OR 1.6, 95% CI 1.3, 1.8, P <.0001), and gestational age at entry (OR 1.3, 95% CI 1.1-1.5, P =.002) were significant at the.05 level for predicting successful induction. A multivariate stepwise logistic regression was then performed to evaluate each of these as independent predictors. Parity (OR 2.4, 95% CI 2.0-3.0, P <.0001), initial cervical dilatation (OR 1.7, 95% CI 1.4-2.1, P <.0001), and estimated gestational age (OR 1.3, 95% CI 1.1-1.6, P =.003) are significant independent predictors for successful induction, but initial Bishop score is not significant (P =.19) after adjustment for other significant predicting factors. CONCLUSIONS: The clinical characteristics of parity, initial cervical dilatation, and gestational age at entry are predictors of the likelihood of success of cervical ripening and labor induction with intravaginal misoprostol administration.     

Risk factors for arrest of descent during the second stage of labor.

OBJECTIVE: To define obstetrical risk factors for arrest of descent during the second stage of labor and to determine perinatal outcome. STUDY DESIGN: All singleton, vertex, term deliveries with an unscarred uterus, between the years 1988 and 1999 were included. Univariable and multivariable analysis were performed to investigate independent risk factors associated with arrest of descent during the second stage of labor and the perinatal outcome. RESULTS: The study included 93266 deliveries, of these 1545 (1.7%) were complicated with arrest of descent during the second stage of labor. Using a multivariable analysis, the following obstetric risk factors were found to be significantly associated with arrest of descent: nulliparity (OR=7.8, 95% CI=6.9-8.7; P<0.001), birth weight >4 kg (OR=2.3, 95% CI=1.9-2.8; P<0.001), epidural analgesia (OR=1.8, 95% CI=1.6-2.0; P<0.001), hydramnios (OR=1.6, 95% CI=1.3-2.0; P<0.001), hypertensive disorders (OR=1.5, 95% CI=1.3-1.8; P<0.001), gestational diabetes A1 and A2 (OR=1.5, 95% CI=1.2-1.8; P<0.001), male gender (OR=1.4, 95% CI=1.2-1.5; P<0.001), premature rupture of membranes (PROM, OR=1.3, 95% CI=1.04-1.6; P=0.021), and induction of labor (OR=1.2, 95% CI=1.02-1.4; P=0.030). Deliveries complicated by arrest of descent resulted in cesarean section in 20.6%, vacuum extraction in 74.0%, and forceps delivery in 5.4%. Newborns delivered after arrest of descent during the second stage of labor had significantly higher rates of low Apgar scores (<7) at 1 and 5 min, as compared to the controls (12.7 vs. 2.1%, P<0.001; and 0.9 vs. 0.2%, P<0.001, respectively). Nevertheless, no significant differences were noted between the groups regarding perinatal mortality (0.38 vs. 0.44%; P=0.759). CONCLUSIONS: Major risk factors for arrest of descent during the second stage of labor were nulliparity, fetal macrosomia, epidural analgesia, hydramnios, hypertensive disorders and gestational diabetes mellitus. These risk factors should be carefully evaluated during pregnancy in order to actively manage high-risk pregnancies.     

Placenta previa: obstetric risk factors and pregnancy outcome

Objective: To determine the incidence, obstetric risk factors and perinatal outcome of placenta previa. Study design: All singleton deliveries at our institution between 1990 and 1998 complicated with placenta previa were compared with those without placenta previa. Results: Placenta previa complicated 0.38% ( n = 298) of all singleton deliveries ( n = 78 524). A back-step multiple logistic regression model found the following factors to be independently correlated with the occurrence of placenta previa: maternal age above 40 years (OR 3.1, 95% CI 2.0-4.9), infertility treatments (OR 3.1, 95% CI 1.8-5.6), a previous Cesarean section (OR 1.8, 95% CI 1.4-2.4), a history of habitual abortions (OR 1.3, 95% CI 1.3-2.7) and Jewish ethnicity (OR 1.3, 95% CI 1.1-1.8). Pregnancies complicated with placenta previa had significantly higher rates of second-trimester bleeding (OR 156.0, 95% CI 87.2-277.5), pathological presentations (OR 7.6, 95% CI 5.7-10.1), abruptio placentae (OR 13.1, 95% CI 8.2-20.7), congenital malformations (OR 2.6, 95% CI 1.5-4.2), perinatal mortality (OR 2.6, 95% CI 1.1-5.6), Cesarean delivery (OR 57.4, 95% CI 40.7-81.4), Apgar scores at 5 min lower than 7 (OR 4.4, 95% CI 2.3-8.3), placenta accreta (OR 3.6, 95% CI 1.1-9.9) postpartum hemorrhage (OR 3.8, 95% CI 1.2-10.5), postpartum anemia (OR 5.5, 95% CI 4.4-6.9) and delayed maternal and infant discharge from the hospital (OR 10.9, 95% CI 7.3-16.1) as compared to pregnancies without placenta previa. In a multivariable analysis investigating risk factors for perinatal mortality, the following were found to be independent significant factors: congenital malformations, placental abruption, pathological presentations and preterm delivery. In contrast, placenta previa and Cesarean section were found to be protective factors against the occurrence of perinatal mortality while controlling for confounders. Conclusion: Although an abnormal implantation per se was not an independent risk factor for perinatal mortality, placenta previa should be considered as a marker for possible obstetric complications. Hence, the detection of placenta previa should encourage a careful evaluation with timely delivery in order to reduce the associated maternal and perinatal complications.     

Placenta previa: obstetric risk factors and pregnancy outcome.

OBJECTIVE: To determine the incidence, obstetric risk factors and perinatal outcome of placenta previa. STUDY DESIGN: All singleton deliveries at our institution between 1990 and 1998 complicated with placenta previa were compared with those without placenta previa. RESULTS: Placenta previa complicated 0.38% (n = 298) of all singleton deliveries (n = 78 524). A back-step multiple logistic regression model found the following factors to be independently correlated with the occurrence of placenta previa: maternal age above 40 years (OR 3.1, 95% CI 2.0-4.9), infertility treatments (OR 3.1, 95% CI 1.8-5.6), a previous Cesarean section (OR 1.8, 95% CI 1.4-2.4), a history of habitual abortions (OR 1.3, 95% CI 1.3-2.7) and Jewish ethnicity (OR 1.3, 95% CI 1.1-1.8). Pregnancies complicated with placenta previa had significantly higher rates of second-trimester bleeding (OR 156.0, 95% CI 87.2-277.5), pathological presentations (OR 7.6, 95% CI 5.7-10.1), abruptio placentae (OR 13.1, 95% CI 8.2-20.7), congenital malformations (OR 2.6, 95% CI 1.5-4.2), perinatal mortality (OR 2.6, 95% CI 1.1-5.6), Cesarean delivery (OR 57.4, 95% CI 40.7-81.4), Apgar scores at 5 min lower than 7 (OR 4.4, 95% CI 2.3-8.3), placenta accreta (OR 3.6, 95% CI 1.1-9.9) postpartum hemorrhage (OR 3.8, 95% CI 1.2-10.5), postpartum anemia (OR 5.5, 95% CI 4.4-6.9) and delayed maternal and infant discharge from the hospital (OR 10.9, 95% CI 7.3-16.1) as compared to pregnancies without placenta previa. In a multivariable analysis investigating risk factors for perinatal mortality, the following were found to be independent significant factors: congenital malformations, placental abruption, pathological presentations and preterm delivery. In contrast, placenta previa and Cesarean section were found to be protective factors against the occurrence of perinatal mortality while controlling for confounders. CONCLUSION: Although an abnormal implantation per se was not an independent risk factor for perinatal mortality, placenta previa should be considered as a marker for possible obstetric complications. Hence, the detection of placenta previa should encourage a careful evaluation with timely delivery in order to reduce the associated maternal and perinatal complications.     

Beta-thalassemia minor during pregnancy

OBJECTIVE: To investigate pregnancy outcome of patients with beta-thalassemia minor. METHODS: A population-based study comparing all pregnancies of women with and without beta-thalassemia minor was conducted. Deliveries occurred during the years 1988-2002 at Soroka University Medical Center. A multivariate logistic regression model, with backward elimination, was constructed to find independent risk factors associated with maternal beta-thalassemia minor. RESULTS: During the study period there were 159,195 deliveries, of which 261 (0.2%) occurred in patients with beta-thalassemia minor. The following conditions were significantly associated with beta-thalassemia minor: oligohydramnios (odds ratio [OR] 2.1; 95% confidence interval [CI] 1.2%, 3.7%), intrauterine growth restriction (IUGR; OR 2.4; 95% CI 1.4%, 4.2%), Jewish ethnicity (OR 1.5; 95% CI 1.2%, 1.9%), and previous cesarean delivery (OR 1.4; 95% CI 1.1%, 2.0%). No significant differences were noted between the groups regarding perinatal outcomes such as birth weight, low Apgar scores, congenital malformations, or perinatal mortality. Patients with beta-thalassemia minor were more likely to have cesarean deliveries than were the nonthalassemic parturients (16.9% and 12.2%, respectively; P =.021). However, while controlling for possible confounders such as IUGR, oligohydramnios, and previous cesarean delivery, with another multivariate analysis with cesarean delivery as the outcome variable, beta-thalassemia minor was not found as an independent risk factor for cesarean delivery (OR 1.3; 95% CI 0.9%, 1.9%). CONCLUSION: The course of pregnancy of patients with thalassemia minor, including perinatal outcomes, is favorable. Because higher rates of IUGR were found, we recommend ultrasound surveillance of fetal weight for early detection of IUGR. LEVEL OF EVIDENCE: II-2     

Models for the prediction of successful induction of labor based on pre-induction sonographic measurement of cervical length.

OBJECTIVE: To examine the effect of pre-induction cervical length, parity, gestational age at induction, maternal age and body mass index (BMI) on the possibility of successful delivery in women undergoing induction of labor. METHODS: In 822 singleton pregnancies, induction of labor was carried out at 35 to 42(+6) weeks of gestation. The cervical length was measured by transvaginal sonography before induction. The effect of cervical length, parity, gestational age, maternal age and BMI on the interval between induction and vaginal delivery within 24 hours was investigated using Cox's proportional hazard model. The likelihood of vaginal delivery within 24 hours and risk for cesarean section overall and for failure to progress was investigated using logistic regression analysis. RESULTS: Successful vaginal delivery within 24 hours of induction occurred in 530 (64.5%) of the 822 women. Cesarean sections were performed in 161 (19.6%) cases, 70 for fetal distress and 91 for failure to progress. Cox's proportional hazard model indicated that significant prediction of the induction-to-delivery interval was provided by the pre-induction cervical length (HR=0.89, 95% CI 0.88-0.90, p<0.0001), parity (HR=2.39, 95% CI 1.98-2.88, p<0.0001), gestational age (HR=1.13, 95% CI 1.07-1.2, p=or<0.0001) and birth weight percentile (HR=0.995, 95% CI 0.99-0.995, p=0.001), but not by maternal age or BMI. Logistic regression analysis indicated that significant prediction of the likelihood of vaginal delivery within 24 hours was provided by pre-induction cervical length (OR=0.86, 95% CI 0.84-0.88, p<0.0001), parity (OR=3.59, 95% CI 2.47-5.22, p<0.0001) and gestational age (OR=1.19, 95% CI 1.07-1.32, p=or<0.0001) but not by BMI or maternal age. The risk of cesarean section overall was significantly associated with all the variables under consideration, i.e., pre-induction cervical length (OR=1.09, 95% CI 1.06-1.11, p<0.0001), parity (OR=0.25, 95% CI 0.17-0.38, p<0.0001), BMI (OR=1.85, 95% CI 1.24-2.74, p=0.0024), gestational age (OR=0.88, 95% CI 0.78-0.98, p=0.0215) and maternal age (OR=1.04, 95% CI 1.01-1.07, p=0.0192). The risk of cesarean section for failure to progress was also significantly associated with pre-induction cervical length (OR=1.11, 95% CI 1.07-1.14, p<0.0001), parity (OR=0.26, 95% CI 0.15-0.43, p<0.0001), gestational age (OR=0.83, 95% CI 0.73-0.96, p=0.0097) and BMI (OR=2.07, 95% CI 1.27-3.37, p=0.0036). CONCLUSION: In women undergoing induction of labor, pre-induction cervical length, parity, gestational age at induction, maternal age and BMI have a significant effect on the interval between induction and delivery within 24 hours, likelihood of vaginal delivery within 24 hours and the risk of cesarean section.     

Uterine rupture: risk factors and pregnancy outcome

OBJECTIVES: This study aimed at determining risk factors and pregnancy outcome in women with uterine rupture. STUDY DESIGN: We conducted a population-based study, comparing all singleton deliveries with and without uterine rupture between 1988 and 1999. RESULTS: Uterus rupture occurred in 0.035% (n=42) of all deliveries included in the study (n=117,685). Independent risk factors for uterine rupture in a multivariable analysis were as follows: previous cesarean section (odds ratio [OR]=6.0, 95% CI 3.2-11.4), malpresentation (OR=5.4, 95% CI 2.7-10.5), and dystocia during the second stage of labor (OR=13.7, 95% CI 6.4-29.3). Women with uterine rupture had more episodes of postpartum hemorrhage (50.0% vs 0.4%, P<.01), received more packed cell transfusions (54.8% vs 1.5%, P<.01), and required more hysterectomies (26.2% vs 0.04%, P<.01). Newborn infants delivered after uterine rupture were more frequently graded Apgar scores lower than 5 at 5 minutes and had higher rates of perinatal mortality when compared with those without rupture (10.3% vs 0.3%, P<.01; 19.0% vs 1.4%, P<.01, respectively). CONCLUSION: Uterine rupture, associated with previous cesarean section, malpresentation, and second-stage dystocia, is a major risk factor for maternal morbidity and neonatal mortality. Thus, a repeated cesarean delivery should be considered among parturients with a previous uterine scar, whose labor failed to progress.     

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.     

Risk factors and outcome of failure to progress during the first stage of labor: a population-based study

BACKGROUND: One of the major indications for Cesarean section (CS) is failure of labor to progress. This study was aimed at defining obstetric risk factors for failure of labor to progress during the first stage, and to determine pregnancy outcome. METHODS: A population-based study comparing all singleton, vertex, term deliveries between the years 1988 and 1999 with an unscarred uterus, complicated with failure of labor to progress during the first stage with deliveries without non-progressive labor (NPL). Multiple logistic regression analysis was performed to investigate independent obstetric risk factors associated with failure of labor to progress during the first stage. RESULTS: Failure to progress during the first stage of labor complicated 1.3% (n = 1197) of all deliveries included in the study (n = 92 918), and resulted in CS. Independent risk factors for failure of labor to progress during the first stage, using a multivariable analysis, were premature rupture of membranes (PROM; OR = 3.8, 95% CI 3.2-4.5), nulliparity (OR = 3.8, 95% CI 3.3-4.3), labor induction (OR = 3.3, 95% CI 2.9-3.7), maternal age > 35 years (OR = 3.0, 95% CI 2.6-3.6), birth weight > 4 kg (OR = 2.2, 95% CI 1.8-2.7), hypertensive disorders (OR = 2.1, 95% CI 1.8-2.6), hydramnios (OR = 1.9, 95% CI 1.5-2.3), fertility treatment (OR = 1.8, 95% CI 1.4-2.4), epidural analgesia (OR = 1.6, 95% CI 1.4-1.8) and gestational diabetes (OR = 1.4, 95% CI 1.1-1.7). Although newborns delivered after failure of labor to progress during the first stage had significantly higher rates of Apgar scores lower than 7 at 1 and 5 min as compared with the controls (18.2% vs. 2.1%; P < 0.001 and 1.3% vs. 0.2%; P < 0.001, respectively), no significant differences were noted between the groups regarding perinatal mortality (0.3% vs. 0.4%; P = O.329). Maternal anemia and accordingly packed cells transfusion (47.4% vs. 22.8%; P < 0.001 and 5.6% vs. 1.0%; P < 0.001, respectively) were higher among pregnancies complicated with failure of labor to progress during the first stage as compared with the controls. CONCLUSIONS: Major risk factors for failure of labor to progress during the first stage were PROM, nulliparity, induction of labor and older maternal age. Indications for labor induction should be carefully evaluated in order to decrease the rate of operative deliveries.     

Maternal anemia during pregnancy is an independent risk factor for low birthweight and preterm delivery

OBJECTIVE: The present study was designed to investigate the outcome of pregnancy and delivery in patients with anemia. METHODS: A retrospective population-based study comparing all singleton pregnancies of patients with and without anemia was performed. Deliveries occurred during the years 1988-2002 in the Soroka University Medical Center. Maternal anemia was defined as hemoglobin concentration lower than 10 g/dl during pregnancy. Patients with hemoglobinopathies such as thalassemia were excluded from the analysis. Multiple logistic regression models were performed to control for confounders. RESULTS: During the study period there were 153,396 deliveries, of which 13,204 (8.6%) occurred in patients with anemia. In a multivariable analysis, the following conditions were significantly associated with maternal anemia: placental abruption, placenta previa, labor induction, previous cesarean section (CS), non-vertex presentation and Bedouin ethnicity. Higher rates of preterm deliveries (<37 weeks gestation) and low birthweight (<2500 g) were found among patients with anemia as compared to the non-anemic women (10.7% versus 9.0%, p < 0.001 and 10.5% versus 9.4%, p < 0.001; respectively). Higher rates of CS were found among anemic women (20.4% versus 10.3%; p < 0.001). The significant association between anemia and low birthweight persisted after adjusting for gender, ethnicity and gestational age, using a multivariable analysis (OR = 1.1; 95% CI 1.0-1.2, p = 0.02). Two multivariable logistic regression models, with preterm delivery (<37 weeks gestation) and low birthweight (<2500 g) as the outcome variables, were constructed in order to control for possible confounders such as ethnicity, maternal age, placental problems, mode of delivery and non-vertex presentation. Maternal anemia was an independent risk factor for both, preterm delivery (OR = 1.2; 95% CI 1.1-1.2, p < 0.001) and low birthweight (OR = 1.1; 95% CI 1.1-1.2, p = 0.001). CONCLUSION: Maternal anemia influences birthweight and preterm delivery, but in our population, is not associated with adverse perinatal outcome.     

Chronic hypertension and the risk for adverse pregnancy outcome after superimposed pre-eclampsia.

OBJECTIVE: To determine the risk factors and pregnancy outcome of patients with chronic hypertension during pregnancy after controlling for superimposed preeclampsia. METHOD: A comparison of all singleton term (>36 weeks) deliveries occurring between 1988 and 1999, with and without chronic hypertension, was performed. Stratified analyses, using the Mantel-Haenszel technique, and a multiple logistic regression model were performed to control for confounders. RESULTS: Chronic hypertension complicated 1.6% (n=1807) of all deliveries included in the study (n=113156). Using a multivariable analysis, the following factors were found to be independently associated with chronic hypertension: maternal age >40 years (OR=3.1; 95% CI 2.7-3.6), diabetes mellitus (OR=3.6; 95% CI 3.3-4.1), recurrent abortions (OR=1.5; 95% CI 1.3-1.8), infertility treatment (OR=2.9; 95% CI 2.3-3.7), and previous cesarean delivery (CD; OR=1.8 CI 1.6-2.0). After adjustment for superimposed preeclampsia, using the Mantel-Haenszel technique, pregnancies complicated with chronic hypertension had higher rates of CD (OR=2.7; 95% CI 2.4-3.0), intra uterine growth restriction (OR=1.7; 95% CI 1.3-2.2), perinatal mortality (OR=1.6; 95% CI 1.01-2.6) and post-partum hemorrhage (OR=2.2; 95% CI 1.4-3.7). CONCLUSION: Chronic hypertension is associated with adverse pregnancy outcome, regardless of superimposed preeclampsia.     

Umbilical cord prolapse and perinatal outcomes.

OBJECTIVES: To determine obstetric risk factors and perinatal outcomes of pregnancies complicated by umbilical cord prolapse. METHODS: A population-based study was performed comparing all deliveries complicated by cord prolapse to deliveries without this complication. Statistical analysis was performed using multiple logistic regression models. RESULTS: Prolapse of the umbilical cord complicated 0.4% (n=456) of all deliveries included in the study (n=121,227). Independent risk factors for cord prolapse identified by a backward, stepwise multivariate logistic regression model were: malpresentation (OR=5.1; 95% CI 4.1-6.3), hydramnios (OR=3.0; 95% CI 2.3-3.9), true knot of the umbilical cord (OR=3.0; 95% CI 1.8-5.1), preterm delivery (OR=2.1; 95% CI 1.6-2.8), induction of labor (OR=2.2; 95% CI 1.7-2.8), grandmultiparity (>five deliveries, OR=1.9; 95% CI 1.5-2.3), lack of prenatal care (OR=1.4; 95% CI 1.02-1.8), and male gender (OR=1.3; 95% CI 1.1-1.6). Newborns delivered after umbilical cord prolapse graded lower Apgar scores, less than 7, at 5 min (OR=11.9, 95% CI 7.9-17.9), and had longer hospitalizations (mean 5.4+/-3.5 days vs. 2.9+/-2.1 days; P<0.001). Moreover, higher rates of perinatal mortality were noted in the cord prolapse group vs. the control group (OR=6.4, 95% CI 4.5-9.0). Using a multiple logistic regression model controlling for possible confounders, such as preterm delivery, hydramnios, etc., umbilical cord prolapse was found to be an independent contributing factor to perinatal mortality. CONCLUSIONS: Prolapse of the umbilical cord is an independent risk factor for perinatal mortality.     

Perinatal factors associated with cerebral palsy in children born in Sweden

OBJECTIVE: To identify perinatal factors associated with cerebral palsy (CP). METHODS: This was a case-control study based on the Swedish Medical Birth Registry and the Swedish Hospital Discharge Registry, including 2,303 infants born in Sweden 1984-1998 with a diagnosis of CP and 1.6 million infants without this diagnosis. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. RESULTS: Infants born preterm had a highly increased risk for CP, and constituted 35% of all cases; OR 34 (95% CI 29-39) in weeks 23-27, OR 37 (95% CI 32-42) in weeks 28-29, OR 26 (95% CI 23-30) in weeks 30-31, and OR 3.9 (95% CI 3.4-4.4) in weeks 32-36. Boys had a higher risk (sex ratio 1.36:1), particularly before term (sex ratio 1.55:1). Other factors associated with CP were being small or large for gestational age at birth, abruptio placentae (OR 8.6, 95% CI 5.6-13.3), maternal insulin-dependent diabetes mellitus type 1 (OR 2.1, 95% CI 1.4-3.1), preeclampsia (OR 1.5, 95% CI 1.3-2.4), being a twin (OR 1.4, 95% CI 1.1-1.6), maternal age older than 40 years (OR 1.4, 95% CI 1.1-1.8) or 35-39 years (OR 1.2, 95% CI 1.1-1.4), primiparity (OR 1.2, 95% CI 1.1-1.3), and smoking (OR 1.2, 95% CI 1.1-1.3). In term infants, low Apgar scores were associated with a high risk for CP; OR 62 (95% CI 52-74) at score 6 at 5 minutes, OR 498 (95% CI 458-542) at score 3. Other factors associated with CP in term infants were breech presentation at vaginal birth (OR 3.0, 95% CI 2.4-3.7), instrumental delivery (OR 1.9, 95% CI 1.6-2.3), and emergency cesarean delivery (OR 1.8, 95% CI 1.6-2.0). CONCLUSION: Preterm birth entails a high risk for CP, but 65% of these children are born at term. Several obstetric factors and low Apgar scores are associated with CP. LEVEL OF EVIDENCE: II-2.     

Prevalence of maternal obesity in an urban center

OBJECTIVE: The purpose of this study was to evaluate the changing prevalence of maternal obesity in an urban center. STUDY DESIGN: The prevalence of obesity in 31,542 pregnancies from January 1986 to December 1996 (group 1) was compared with the prevalence of obesity in 15,600 pregnancies between January 1997 and June 2001 (group 2). Maternal weight was divided into two groups according to measurements performed at delivery (200 pounds). Women who weighed >or=200 pounds were divided into subgroups for analysis (201-250 pounds, 251-300 pounds, and >300 pounds). The incidence of obesity by weight group was evaluated for a change over time; the impact of race and socioeconomic status was analyzed. A probability value of <.05 was considered significant. RESULTS: Maternal obesity was significantly more common in group 2 (>200 pounds: 28% vs 21%; relative risk, 1.3; 95% CI, 1.3-1.4; 201-250 pounds: 20% vs 16%; relative risk, 1.3; 95% CI, 1.2-1.3; 251-300 pounds: 5.5% vs 3.7%; relative risk, 1.5; 95% CI, 1.3-1.6; >300 pounds: 1.6% vs 1.2%; relative risk, 1.4; 95% CI,1.2-1.7; P <.001 for each). Obesity was most common in African American women (>200 pounds, 28.1%; 201-250 pounds, 20.5%; 251-300 pounds, 5.5%; and >300 pounds, 2.1 %). The prevalence of obesity increased most among African American women (>200 pounds: 35 % vs 25%; relative risk, 1.4; 95% CI, 1.4-1.5; 201-250 pounds: 25 % vs 18%; relative risk, 1.4; 95% CI, 1.3-1.5; 251-300 pounds: 7.3 % vs 4.6%; relative risk, 1.6; 95% CI, 1.4-1.6; >300 pounds: 2.7% vs 1.8%; relative risk, 1.5; 95% CI, 1.3-1.9; P <.001 for each), and it decreased in Asian women (>200 pounds: 6.8% vs 11%; relative risk, 0.6; 95% CI, 0.4-0.9; P <.05; 201-250 pounds: 6.3% vs 9.7%; relative risk, 0.6; 95% CI, 0.4 -1.1; P >.05; 251-300 pounds: 0.6% vs 1%; relative risk, 0.6; 95% CI, 0.1- 2.9; P >.05; >300 pounds: 0.0% vs 0.3%). The increase in weight over time remained statistically significant after being controlled in multivariate analysis for socioeconomic status and race. Women with milder obesity (201-250 pounds prepregnancy weight) were at increased risk for preeclampsia, gestational and insulin-dependent diabetes mellitus, advanced gestational age (>or=42 weeks), fetal macrosomia, and cesarean delivery (P <.001 for each), with increasing weight being associated with higher risk. CONCLUSION: Obesity that complicates pregnancy has increased significantly over the past 15 years. The risk of perinatal complications increases with increasing maternal pregravid weight; even those women with moderate obesity are at increased risk of adverse outcomes.     

Obstetric outcome in women with subfertility

BACKGROUND: It has been suggested that a history of subfertility is associated with increased obstetric and perinatal risks. It is unclear if the cause is inherent characteristics in the women or the fertility treatment. OBJECTIVES: To compare the obstetric and perinatal risks of singleton pregnancies in women with a history of subfertility in comparison with the general population. DESIGN: Population cohort. SETTING: Aberdeen, Scotland. POPULATION: Cases were women attending the Fertility Clinic between 1989 and 1999 who subsequently went on to have singleton pregnancies. Controls included the general population of women who delivered singletons over the same period. METHODS: We performed a retrospective cohort study to investigate the obstetric outcome of singleton pregnancies in women with subfertility. The general population of women who delivered singletons over the same period served as controls. MAIN OUTCOME MEASURES: Obstetric and perinatal complications in singleton pregnancies. RESULTS: Maternity records were available for a total of 1437 subfertile women and 21,688 controls. Subfertile women were older [mean (SD) age: 31 (4.7) years vs 27 (5.4) years, P < 0.01] and more likely to be primiparous (70% vs 65%, P < 0.001). After adjusting for age and parity, subfertile women were at increased risk of pre-eclampsia (OR 1.9, 95% CI 1.5-2.5), placenta praevia (OR 3.9, 95% CI 2.2-7.0) and placental abruption (OR 1.8, 95% CI 1.1-3.0), and more likely to undergo induction of labour (OR 1.5, 95% CI 1.3-1.6), caesarean section (OR 2.1, 95% CI 1.8-2.4) and instrumental delivery (OR 2.2, 95% CI 1.8-2.6), and deliver low birthweight (OR 1.4, 95% CI 1.3-1.7) and preterm (OR 1.7, 95% CI 1.2-2.2) infants. There were no differences between treatment-related and treatment-independent pregnancies. CONCLUSION: Subfertile women are at higher risk of obstetric complications, which persist after adjusting for age and parity.     

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.     

Perinatal outcomes in singletons following in vitro fertilization: a meta-analysis

OBJECTIVE: To estimate whether singleton pregnancies following in vitro fertilization (IVF) are at higher risk of perinatal mortality, preterm delivery, small for gestational age, and low or very low birth weight compared with spontaneous conceptions in studies that adjusted for age and parity. DATA SOURCES: We searched MEDLINE, BIOSIS, Doctoral Dissertations On-Line, bibliographies, and conference proceedings for studies from 1978-2002 using the terms "in vitro fertilization," "female infertility therapy," and "reproductive techniques" combined with "fetal death," "mortality," "fetal growth restriction," "small for gestational age," "birth weight," "premature labor," "pre-term delivery," "infant," "obstetric," "perinatal," and "neonatal." METHODS OF STUDY SELECTION: Inclusion criteria were singleton pregnancies following IVF compared with spontaneous conceptions, control for maternal age and parity; 1 of the above outcomes; and risk ratios or data to determine them. Study selection and data abstraction were performed in duplicate after removing identifying information. TABULATION, INTEGRATION, AND RESULTS: Fifteen studies comprising 12,283 IVF and 1.9 million spontaneously conceived singletons were identified. Random-effects meta-analysis was performed. Compared with spontaneous conceptions, IVF singleton pregnancies were associated with significantly higher odds of each of the perinatal outcomes examined: perinatal mortality (odds ratio [OR] 2.2; 95% confidence interval [CI] 1.6, 3.0), preterm delivery (OR 2.0; 95% CI 1.7, 2.2), low birth weight (OR 1.8; 95% CI 1.4, 2.2), very low birth weight (OR 2.7; 95% CI 2.3, 3.1), and small for gestational age (OR 1.6; 95% CI 1.3, 2.0). Statistical heterogeneity was noted only for preterm delivery and low birth weight. Sensitivity analyses revealed no significant changes in results. Early preterm delivery, spontaneous preterm delivery, placenta previa, gestational diabetes, preeclampsia, and neonatal intensive care admission were also significantly more prevalent in the IVF group. CONCLUSION: In vitro fertilization patients should be advised of the increased risk for adverse perinatal outcomes. Obstetricians should not only manage these pregnancies as high risk but also avoid iatrogenic harm caused by elective preterm labor induction or cesarean.     

Risk factors for placental abruption in an Asian population

The objective of this study was to identify risk factors for placental abruption in an Asian population. The authors conducted a retrospective review of 37 245 Taiwanese women who delivered between July 1990 and December 2003. Pregnancies complicated by placenta previa, multiple gestation, and fetal anomalies were excluded. Multivariable logistic regression was used to adjust for potentially confounding variables and to identify independent risk factors for placental abruption. Three hundred thirty-two women had placental abruption (9 per 1000 singleton deliveries). Women who smoked during pregnancy (adjusted odds ratio [OR] = 8.4; 95% confidence interval [CI] = 3.0-23.9), had gestational hypertensive diseases (adjusted OR = 4.9; 95% CI = 3.3-7.3), pregnancies complicated by oligohydramnios (adjusted OR = 4.2; 95% CI = 2.7-6.7), polyhydramnios (adjusted OR = 3.3; 95% CI = 1.4-7.7), preterm premature rupture of membranes (adjusted OR = 1.9; 95% CI = 1.1-3.1), entanglement of umbilical cord (adjusted OR = 1.6; 95% CI = 1.2-2.1), were of or more than 35 years of age (adjusted OR = 1.5; 95% CI = 1.1-2.0), and had a low prepregnancy body mass index (adjusted OR = 1.3; 95% CI = 1.0-1.6) were at increased risk for placental abruption. Some risk factors for placental abruption among Taiwanese women are the same as those of other ethnic groups, whereas some of the risk factors are different.