Cesarean delivery and subsequent pregnancies

OBJECTIVE: To assess possible effects of a cesarean delivery on outcome in subsequent pregnancies. METHODS: Using an historical cohort design, we analyzed 637,497 first and second births among women with two or more single births and 242,812 first, second, and third births among women with three or more single births registered in the population-based Medical Birth Registry of Norway between 1967 and 2003. RESULTS: Compared with a vaginal delivery at first birth, a cesarean delivery at first birth was followed, in a second pregnancy, by increased risks of preeclampsia (odds ratio [OR] 2.9 and corresponding 95% confidence interval [CI] 2.8-3.1), small for gestational age (OR 1.5; CI 1.4-1.5), placenta previa (OR 1.5; CI 1.3-1.8, placenta accreta (OR 1.9; CI 1.3-2.8), placental abruption (OR 2.0; CI 1.8-2.2), and uterine rupture (OR 37.4; CI 24.9-56.2). After excluding women with the actual complication at first birth, the corresponding ORs were, in general, lower: 1.7 (CI 1.6-1.8), 1.3 (CI 1.3-1.4), 1.4 (CI 1.2-1.7), 1.9 (CI 1.3-2.8), 1.7 (CI 1.6-1.9), and 37.2 (CI 24.7-55.9), respectively. Corresponding reduction in numbers of cesarean deliveries needed to prevent one case were 114, 56, 1,140, 3,706, 300, and 461. In third births, ORs after repeat cesarean delivery were similar to or lower than the ORs after one cesarean delivery; also here, the exclusion of women with the actual outcome in any of their previous pregnancies tended to reduce the ORs. CONCLUSION: Cesarean delivery was associated with an increased risk of complications in a subsequent pregnancy, but excess risks were reduced after excluding women with the actual complication in any of their previous births. To obtain less biased effects of cesarean delivery on subsequent pregnancies, it is important to account for obstetric history. LEVEL OF EVIDENCE: II.     

Combined vaginal-cesarean delivery of twin pregnancies.

OBJECTIVE: To estimate the incidence and factors associated with combined vaginal-cesarean delivery in twin pregnancies. METHODS: We studied all twin births weighing 500 g or more during a 20-year period (1980-1999) at a tertiary care center. Major anomalies, monoamniotic and conjoined twins, and antepartum fetal deaths were excluded. RESULTS: During this 20-year period, 105,987 women delivered, of whom 1565 (1.5%) had twins. Of these, 1151 twin sets fulfilled the study criteria. The mode of delivery was vaginal in 653 (56.8%), cesarean in 448 (38.9%), and vaginal-cesarean in 50 (4.3%). During the 20 years there was a statistically significant increase in combined vaginal-cesarean and elective cesarean deliveries, with a decrease in vaginal deliveries. Parity, gestational age, and birth weight discordance (>25%) were not associated with combined delivery. Compared with vaginal delivery, the nonvertex second twin was associated with a twofold higher risk of cesarean delivery (relative risk [RR] 2.3; 95% confidence interval [CI] 1.3, 3.8; P =.002); and an interdelivery interval of over 60 minutes with an eightfold higher risk (RR 8.2; CI 4.6,14.6; P <.001). Vaginal-cesarean delivery had a 22-fold higher use of general anesthesia compared with vaginal delivery (RR 21.8; CI 5.4, 88.5; P <.001). CONCLUSION: There has been a significant increase in combined vaginal-cesarean and elective cesarean deliveries among twin gestations, with a decrease in vaginal births. Vaginal-cesarean delivery is associated with nonvertex second twin and a prolonged interdelivery interval.     

Risk factors for postpartum hemorrhage requiring transfusion in cesarean deliveries for Japanese twins: comparison with those for singletons

Objective

The aim of this study was to identify the factors associated with the increased risk of postpartum hemorrhage requiring transfusion in Japanese twin pregnancies in comparison with those in Japanese singleton pregnancies.

Methods

We reviewed the obstetric records of all singleton and twin deliveries after 22?weeks’ gestation at the Japanese Red Cross Katsushika Maternity Hospital from 2003 through 2011. Potential risk factors for transfusion due to hemorrhage after cesarean delivery were selected according to previous studies of postpartum hemorrhage or transfusion or both after delivery: maternal age, parity, previous cesarean deliveries, history of infertility therapies such as in vitro fertilization, gestational age at delivery, neonatal birth weight, placenta previa, uterine myoma ≥6?cm, hypertensive disorders, placental abruption, emergency cesarean deliveries and general anesthesia.

Results

Using multiple logistic regression, the independent risk factors for postpartum hemorrhage requiring transfusion in singleton pregnancies were preterm delivery [odds ratio (OR) 2.40, 95?% confidence interval (CI) 1.2–4.6, p?<?0.01], placenta previa (OR 8.08, 95?% CI 3.9–16, p?<?0.01) and placental abruption (OR 12.8, 95?% CI 2.3–76, p?<?0.01). In twin pregnancies, however, the independent risk factors for postpartum hemorrhage requiring transfusion were gestational age at ≥41?weeks (OR 8.20, 95?% CI 1.3–40, p?<?0.01) and hypertensive disorders (OR 5.45, 95?% CI 2.2–14, p?<?0.01).

Conclusions

The factors associated with postpartum hemorrhage requiring transfusion in cesarean deliveries of twins seemed to be different from those in singleton cesarean deliveries.     

Serious maternal morbidity after childbirth: prolonged hospital stays and readmissions

OBJECTIVE: To determine the frequency of and risk factors for serious morbidity resulting in a prolonged hospital stay or readmission among women enrolled in Tennessee's Medicaid program who delivered live or dead infants in 1991. METHODS: This retrospective cohort study included 33,251 women of white or black ethnicity. Main outcome measures included childbirth-related medical conditions serious enough to result in death, prolonged delivery hospitalization, or readmission within 60 days of delivery. RESULTS: Among 25,810 women with vaginal (78%) and 7441 (22%) women with cesarean deliveries, 2.6% and 8.9%, respectively, had at least one childbirth-related medical condition requiring prolonged delivery hospitalization or readmission, including infection (1.8% and 7.9%), hypertension-related complications (0.7% and 2.0%), or hemorrhage (0.5% and 2.4%). After controlling for other risk factors, maternal age over 32 years was independently associated with increased rate of serious morbidity among women who had vaginal (relative risk [RR] 1.9, 95% confidence interval [CI] 1.4, 2.7) or cesarean deliveries (RR 1.6, 95% CI 1.1, 2.2). Black women had approximately twice the rate of maternal morbidity with vaginal (RR 1.9, 95% CI 1.5, 2.4) or cesarean deliveries (RR 2.3, 95% CI 1.9, 2.9). Primiparous women who had vaginal or cesarean deliveries had a 60% (RR 1.6, 95% CI 1.3, 2.0) and 70% (RR 1.7, 95% CI 1.4, 2.0), respectively, greater risk of serious maternal morbidity than women with 1-3 prior births. CONCLUSION: Predictors of serious maternal morbidity included age over 32 years, black ethnicity, and primiparity.     

Peripartum hysterectomy in Taiwan

OBJECTIVE: To investigate the incidence and associated risk factors for peripartum hysterectomy in singleton pregnancies. METHODS: A retrospective cohort study of all women with singleton pregnancies admitted for delivery in 2002 taken from the National Healthcare Insurance database. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for maternal and hospital characteristics using logistic regression. RESULTS: There were 287 peripartum hysterectomies in 214 237 singleton pregnancies (0.13%). Cesarean delivery, vaginal birth after cesarean (VBAC), and repeat cesarean delivery had higher hysterectomy rates than vaginal delivery, with adjusted ORs of 12.13 (95% CI 8.30-17.74), 5.12 (95% CI 1.19-21.92), and 3.84 (95% CI 2.52-5.86), respectively. Pregnancies complicated with placenta previa, gestational diabetes mellitus (GDM), and premature labor were associated with significantly increased risks for peripartum hysterectomy (P<0.05). CONCLUSION: Risk factors for peripartum hysterectomy included cesarean delivery, VBAC, repeat cesarean, placenta previa, GDM, and premature labor. VBAC and repeat cesarean had a similar risk.     

Oncologic and reproductive outcomes in patients with advanced-stage borderline ovarian tumors

Objective

To examine impact of cesarean delivery in first pregnancy on neonatal mortality and morbidity in second pregnancy.

Study design

Retrospective cohort study using 1995–2002 US birth registration data. Neonatal mortality and morbidity in second pregnancy of cesarean deliveries in the first pregnancy were compared with vaginal deliveries in the first pregnancy.

Results

A total of 9,643,175 singleton second births were eligible in the analysis after excluding those with unknown delivery method (1,801,339 with a previous cesarean delivery and 7,841,836 with a previous vaginal delivery). Compared with vaginal delivery group, infants born to mothers with a previous cesarean delivery had increased risks of assisted ventilation (OR = 1.47, 95% CI 1.46, 1.49), low Apgar's score (OR = 1.14, 95% CI 1.12, 1.17), seizure (OR = 1.36, 95% CI 1.27, 1.45), fetal distress (OR = 1.46, 95% CI 1.44, 1.47), and asphyxia-related neonatal death (OR = 1.40, 95% CI 1.29, 1.52). The association between mode of delivery in first pregnancy and neonatal outcomes in second pregnancy remained the same after excluding women with chronic health problems or adverse birth history and adjusting for potential confounding factors.

Conclusion(s)

Cesarean delivery in first pregnancy is associated with increased risks of neonatal morbidity and mortality in second pregnancy.     

Maternal morbidity associated with cesarean delivery without labor compared with spontaneous onset of labor at term

OBJECTIVE: To estimate the maternal morbidity associated with cesarean deliveries performed at term without labor compared with morbidity associated with spontaneous labor. METHODS: A 14-year, population-based, cohort study (1988-2001) using the Nova Scotia Atlee Perinatal Database compared maternal outcomes in nulliparous women at term undergoing spontaneous labor for planned vaginal delivery with singleton, cephalic presentation and nulliparous women delivering by cesarean without labor. RESULTS: From a total of 18,435 pregnancies, which satisfied inclusion and exclusion criteria, 721 were cesarean deliveries without labor. There were no maternal deaths or transfers for intensive care. There was no difference in wound infection, blood transfusion, or intraoperative trauma. Women undergoing cesarean deliveries without labor were more likely to have puerperal febrile morbidity (relative risk [RR] 2.2; 95% confidence interval [CI] 1.1, 4.5; P=.03), but were less likely to have early postpartum hemorrhage (RR 0.6; 95% CI 0.4, 0.9; P=.01) compared with women entering spontaneous labor. Subgroup analyses of maternal outcomes in women delivering by spontaneous and assisted vaginal delivery and cesarean delivery in labor were also performed. The highest morbidity was found in the assisted vaginal delivery and cesarean delivery in labor groups. CONCLUSION: The increased maternal morbidity in elective cesarean delivery compared with spontaneous onset of labor is limited to puerperal febrile morbidity. Maternal morbidity is increased after assisted vaginal delivery and cesarean delivery in labor compared with cesarean delivery without labor.     

Obstetric history and the risk of placenta previa

OBJECTIVE: To evaluate secular trends in the occurrence of placenta previa and whether placenta previa is associated with the outcome of previous pregnancies, cesarean section, and sociodemographic factors. DESIGN: A cohort study based on the Medical Birth Registry of Norway. Placenta previa in the second pregnancy was investigated for associations with outcomes in the first pregnancy and sociodemographic factors. RESULTS: In birth orders 1 and 2 the occurrence of placenta previa was 1.2 and 2.2 per 1,000, respectively, with no secular trend. The occurrence increased with maternal age and was lowest in women aged 20-29 years. The recurrence rate was 23 per 1,000 (adjusted odds ratio (OR) of recurrence=9.7). In women with prior delivery at < or =25 gestational weeks the risk of placenta previa was 6.7 per 1,000 (adjusted OR=3.0). In women with prior placental abruption the risk was 5.8 per 1,000 (OR=2.6). In women with prior perinatal death the risk was 4.4 per 1,000 (adjusted OR= 1.8). No independent relationship emerged with socio-economic factors, previous birthweight, and a history of pregnancy induced hypertension. Cesarean section was associated with subsequent development of placenta previa (adjusted OR= 1.3). CONCLUSIONS: We found no secular trends in the occurrence of placenta previa. Placenta previa is associated with previously described risk factors for placental abruption. The increased risk of placenta previa subsequent to placental abruption supports the theory of a shared etiologic factor. However, placenta previa and placental abruption do not share a common etiology in relation to a history of pregnancy induced hypertension, fetal growth retardation, and socio-economic factors.     

Risk of maternal postpartum readmission associated with mode of delivery

OBJECTIVE: To determine whether cesarean and operative vaginal deliveries are associated with an increased risk of maternal rehospitalization compared with spontaneous vaginal delivery. METHODS: A population-based cohort study was conducted by using the Canadian Institute for Health Information's Discharge Abstract Database between 1997/1998 and 2000/2001, which included 900,108 women aged 15-44 years with singleton live births (after excluding several selected obstetric conditions). RESULTS: A total of 16,404 women (1.8%) were rehospitalized within 60 days after initial discharge. Compared with spontaneous vaginal delivery (rate 1.5%), cesarean delivery was associated with a significantly increased risk of postpartum readmission (rate 2.7%, odds ratio [OR] 1.9, 95% confidence interval [CI] 1.8-1.9); ie, there was 1 excess postpartum readmission per 75 cesarean deliveries. Diagnoses associated with significantly increased risks of readmission after cesarean delivery (compared with spontaneous vaginal delivery) included pelvic injury/wounds (rate 0.86% versus 0.06%, OR 13.4, 95% CI 12.0-15.0), obstetric complications (rate 0.23% versus 0.08%, OR 3.0, 95% CI 2.6-3.5), venous disorders and thromboembolism (rate 0.07% versus 0.03%, OR 2.7, 95% CI 2.1-3.4), and major puerperal infection (rate 0.45% versus 0.27%, OR 1.8, 95% CI 1.6-1.9). Women delivered by forceps or vacuum were also at an increased risk of readmission (rates 2.2% and 1.8% versus 1.5%; OR forceps: 1.4, 95% CI 1.3-1.5; OR vacuum: 1.2, 95% CI 1.2-1.3, respectively). Higher readmission rates after operative vaginal delivery were due to pelvic injury/wounds, genitourinary conditions, obstetric complications, postpartum hemorrhage, and major puerperal infection. CONCLUSION: Compared with spontaneous vaginal delivery, cesarean delivery, and operative vaginal delivery increase the risk of maternal postpartum readmission. LEVEL OF EVIDENCE: II-2.     

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.     

Elective cesarean delivery for term breech

OBJECTIVE: To compare the maternal complications of elective cesarean delivery for breech at term with those after vaginal or emergency cesarean delivery. METHODS: We conducted a population-based, retrospective cohort study of 15441 primiparas who delivered singleton breech at term. Information was obtained from the Danish Medical Birth Register, the Register of Death Causes, and the Denmark Patient Register. RESULTS: Elective cesarean delivery was associated with lower rates of puerperal fever and pelvic infection (relative risk [RR] 0.81; 95% confidence interval [CI] 0.70, 0.92), hemorrhage and anemia (RR 0.91; 95% CI 0.84, 0.97), and operations for wound infection (RR 0.69; 95% CI 0.57, 0.83) than emergency cesarean delivery. There was a higher rate of puerperal fever and pelvic infection (RR 1.20; 95% CI 1.11, 1.25) than for vaginal delivery. Thromboembolic disease occurred in 0.1% of women with cesarean delivery, and anal sphincter rupture occurred in 1.7% of women with vaginal delivery. Elective cesarean delivery was not associated with subsequent ectopic pregnancy, miscarriage, placental complications, uterine rupture, or adverse neonatal outcome. Women with elective cesarean delivery were more often delivered by elective cesarean in their second pregnancy, compared with women delivered vaginally (RR 1.25; 95% CI 1.21, 1.29). Elective cesarean delivery was associated with a lower rate of a subsequent delivery during the study period and a longer mean delivery interval than for vaginal delivery. CONCLUSION: Elective cesarean delivery for term breech carries a low risk of severe maternal complications.     

Evidence of placental abruption as a chronic process: associations with vaginal bleeding early in pregnancy and placental lesions

BACKGROUND: Clinicians widely regard placental abruption as an acute event, though accumulating data point towards abruption being the end-result of chronic processes early in pregnancy, and perhaps even extending to conception. The Collaborative Perinatal Project was a prospective cohort study performed from 1959 to 1966 in the United States. Since enrolled pregnancies were managed without the biases created by modern perinatal surveillance and interventions, the natural history of disease in these data is ideal to study obstetrical complications such as placental abruption. OBJECTIVE: We assessed the associations versus contributions of the clinical feature of early gestational vaginal bleeding and histologic lesions (chronic and acute) with placental abruption. STUDY DESIGN: Women enrolled in the Collaborative Perinatal Project (1959-1966) were used, restricting the analysis to those that delivered singleton births (n=46,364). Risks of placental abruption were compared between women with and without vaginal bleeding at <20 weeks gestation. We also examined the relationships between placental abruption and chronic and acute histologic lesions, including infarcts, decidual necrosis, presence of macrophages in the decidua, amnion or chorion, and neutrophil infiltration in the amnion, chorion, placental surface, and umbilical vein. RESULTS: Any episode of vaginal bleeding at <20 weeks in pregnancy conferred an increased risk of placental abruption (adjusted relative risk (RR) 1.6, 95% confidence interval (CI) 1.3, 1.8). The greatest risk occurred with bleeding in both the first two trimesters (RR 3.1, 95% CI 2.3, 4.1). The presence of histologic lesions in the placenta, cord and membranes similarly carried an increased risk of placental abruption, even in the absence of vaginal bleeding. The risk of abruption was, however, highest in the presence of both histologic lesions and vaginal bleeding early in pregnancy. CONCLUSION: Vaginal bleeding early in pregnancy and histologic lesions of the placenta, umbilical cord, and membranes are associated with increased risk of placental abruption in later pregnancy. However, the increased risk associated with placental lesions, especially chronic inflammatory lesions, even in the absence of early vaginal bleeding, suggests that prolonged inflammation may be implicated in placental abruption.     

Pregnancy outcome following a previous spontaneous abortion (miscarriage)

OBJECTIVE: To determine the pregnancy outcome following a previous spontaneous abortion (miscarriage). METHOD: A prospective cohort study was done on 300 gravida-2 patients: 200 patients (case group) whose previous pregnancy was spontaneously aborted (early abortion), and 100 patients (control group) whose previous pregnancy went to term and a live fetus was delivered. All the patients were followed until delivery, and then the pregnancy outcomes, neonatal complications and delivery routes were determined and compared between the 2 groups. Pregnancy outcomes included: maternal complications (e.g. placenta previa, placental abruption, premature rupture of the membranes, preeclampsia and eclampsia, abortion, breech presentation, preterm labor, intrauterine fetal death); neonatal complications (low birth weight, gross congenital malformations, low Apgar score at 1 min), and delivery routes (cesarean delivery or instrumental delivery, e.g. forceps or vacuum). Statistical analysis was performed using the Statistical Package for Social Science. RESULTS: Statistical analysis showed that the pregnancy complications following a previous spontaneous miscarriage were no different from those of the control group, except for abortion (16.5 vs. 11%, p < 0.003, RR = 1.15, CI 95% = 0.95-1.39), fetal deaths (1.5 vs. 0%, p < 0.004, RR = 1.51, CI 95% = 1.39-1.63), and vaginal bleeding during the first trimester (19 vs. 1%, p < 0.001, RR = 1.57, CI 95% = 1.41-1.75), which were more than those of the control group. Also, the rate of cesarean delivery (28.14 vs. 13.48%) was increased (p = 0.026, RR = 1.25, CI 95% = 1.07-1.47). Neonatal complications were not statistically significantly different in comparison with the control group. CONCLUSION: A prior spontaneous miscarriage is a risk for the next pregnancy, and the risk of abortion and intrauterine fetal death will increase. Therefore, careful prenatal care is mandatory.     

Early preterm delivery due to placenta previa is an independent risk factor for a subsequent spontaneous preterm birth

ABSTRACT: BACKGROUND: To determine whether patients with placenta previa who delivered preterm have an increased risk for recurrent spontaneous preterm birth. METHODS: This retrospective population based cohort study included patients who delivered after a primary cesarean section (n = 9983). The rate of placenta previa, its recurrence, and the risk for recurrent preterm birth were determined. RESULTS: Patients who had a placenta previa at the primary CS pregnancy had an increased risk for its recurrence [crude OR of 2.65 (95 % CI 1.3-5.5)]. The rate of preterm birth in patients with placenta previa in the primary CS pregnancy was 55.9 %; and these patients had a higher rate of recurrent preterm delivery than the rest of the study population (p < .001). Among patients with placenta previa in the primary CS pregnancy, those who delivered preterm had a higher rate of recurrent spontaneous preterm birth regardless of the location of their placenta in the subsequent delivery [OR 3.09 (95 % CI 2.1-4.6)]. In comparison to all patients with who had a primary cesarean section, patients who had placenta previa and delivered preterm had an independent increased risk for recurrent preterm birth [OR of 3.6 (95 % CI 1.52-8.51)]. CONCLUSIONS: Women with placenta previa, who deliver preterm, especially before 34 weeks of gestation, are at increased risk for recurrent spontaneous preterm birth regardless to the site of placental implantation in the subsequent pregnancy. Thus, strict follow up by high risk pregnancies specialist is recommended.     

The likelihood of placenta previa with greater number of cesarean deliveries and higher parity

OBJECTIVE: To examine the relationship between prior cesarean delivery and placenta previa. METHODS: A hospital-based, case-control study was conducted in which 316 multiparous women with placenta previa were identified. Controls consisted of 2051 multiparous women with spontaneous vaginal deliveries. Information on prior cesarean delivery was examined in three forms: as a dichotomous variable, as an ordinal variable, and as a set of three indicator variables for one, two, and three or more cesarean deliveries. Multivariable logistic regression modeling was used to obtain an adjusted estimate of this association. RESULTS: Women with a prior cesarean delivery were more likely to have a placenta previa than those without (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.21, 2.08). The likelihood of placenta previa increased as both parity and number of cesarean deliveries increased. Thus, the adjusted OR for a primiparous woman with one cesarean delivery was 1.28 (95% CI 0.82, 1.99). For a woman who has four or more deliveries with only a single cesarean delivery, the OR increases to 1.72 (95% CI 1.12, 2.64). This trend continues with greater parity and a greater number of cesarean deliveries such that the likelihood of placenta previa for a woman with parity greater than four and greater than four cesarean deliveries was OR 8.76 (95% CI 1.58, 48.53). CONCLUSION: This study supports the association between prior cesarean delivery and placenta previa and demonstrates that the joint effect of parity and prior cesarean delivery is greater than that of either variable alone.     

The effect of sequential use of vacuum and forceps for assisted vaginal delivery on neonatal and maternal outcomes

OBJECTIVE: To determine the risk of neonatal and maternal disease associated with the sequential use of vacuum and forceps compared with spontaneous vaginal delivery. STUDY DESIGN: Using Washington state birth certificate data linked to hospital discharge records, we compared 3741 vaginal deliveries by both vacuum and forceps, 3741 vacuum deliveries, and 3741 forceps deliveries to 11,223 spontaneous vaginal deliveries. RESULTS: Compared with spontaneous vaginal deliveries, deliveries by sequential use of vacuum and forceps had significantly higher rates of intracranial hemorrhage (relative risk [RR], 3.9; 95% confidence interval [CI], 1.5 to 10.1), brachial plexus (RR, 3.2; 95% CI, 1.6 to 6.4), facial nerve injury (RR, 13.3; 95% CI, 4.7 to 37.7), seizure (RR, 13.7; 95% CI, 2.1 to 88.0), depressed 5-minute Apgar score (RR, 3.0; 95% CI, 2.2 to 4.0), assisted ventilation (RR, 4.8; 95% CI, 2.1 to 11.0), fourth-degree (RR, 11.4; 95% CI, 6.4 to 20.1 among multiparous women) and other lacerations, hematoma (RR, 6.2; 95% CI, 2.1 to 18.1 among multiparous women), and postpartum hemorrhage (RR, 1.6; 95% CI, 1.3 to 2.0). The relative risk of sequential vacuum and forceps use was greater than the sum of the individual relative risks of each instrument for intracranial hemorrhage, facial nerve injury, seizure, hematoma, and perineal and vaginal lacerations. CONCLUSION: Sequential use of vacuum and forceps is associated with increased risk of both neonatal and maternal injury.     

Predicting placental abruption and previa in women with a previous cesarean delivery

The purpose of this study was to determine if placental abruption or previa in women with a history of a prior cesarean delivery (CD) can be predicted. A retrospective cohort study of pregnant women with previous CD was conducted in 17 centers between 1996 and 2000. Women developing placenta previa or abruption in the subsequent pregnancy were compared with those without these complications. Bivariate and multivariable techniques were used to develop predictive models for placenta previa or abruption. The area under the receiver-operator characteristic curves, sensitivity, specificity, and accuracy of the models were compared. Among 25,076 women with prior CD, there were 361 (15 per 1000 births) with placenta previa and 309 (13 per 1000 births) with abruption. The significant risk factors for these complications include advanced maternal age, Asian race, increased parity, illicit drug use, history of spontaneous abortion, and three or more prior cesarean deliveries. Prediction models for abruption and previa had poor sensitivity (12% and 13% for abruption and previa, respectively). In women with at least one prior cesarean delivery, the risk factors for placental previa and abruption can be identified. However, prediction models combining these risk factors were too inefficient to be useful.     

Cesarean delivery and peripartum hysterectomy

OBJECTIVE: To estimate the national incidence of peripartum hysterectomy and quantify the risk associated with cesarean deliveries and other factors. METHODS: A population-based, matched case-control study using the United Kingdom Obstetric Surveillance System, including 318 women in the United Kingdom who underwent peripartum hysterectomy between February 2005 and February 2006 and 614 matched control women. RESULTS: The incidence of peripartum hysterectomy was 4.1 cases per 10,000 births (95% confidence interval [CI] 3.6-4.5). Maternal mortality was 0.6% (95% CI 0-1.5%). Previous cesarean delivery (odds ratio [OR] 3.52, 95% CI 2.35-5.26), maternal age over 35 years (OR 2.42, 95% CI 1.66-3.58), parity of three or greater (OR 2.30, 95% CI 1.26-4.18), previous manual placental removal (OR 12.5, 95% CI 1.17-133.0), previous myomectomy (OR 14.0, 95% CI 1.31-149.3), and twin pregnancy (OR 6.30, 95% CI 1.73-23.0) were all risk factors for peripartum hysterectomy. The risk associated with previous cesarean delivery was higher with increasing numbers of previous cesarean deliveries (OR 2.14 with one previous delivery [95% CI 1.37-3.33], 18.6 with two or more [95% CI 7.67-45.4]). Women undergoing a first cesarean delivery in the current pregnancy were also at increased risk (OR 7.13, 95% CI 3.71-13.7). CONCLUSION: Peripartum hysterectomy is strongly associated with previous cesarean delivery, and the risk rises with increasing number of previous cesarean deliveries, maternal age over 35 years, and parity greater than 3. LEVEL OF EVIDENCE: II.     

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.