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.     

Second-trimester cervical ultrasound: associations with increased risk for recurrent early spontaneous delivery

OBJECTIVE: To determine whether short cervical length or internal os funneling before 20 weeks' gestation predicts early preterm birth or pregnancy loss in women with at least one prior spontaneous early preterm birth. METHODS: Transvaginal cervical ultrasound examinations were done every 2 weeks on 69 women with singleton gestations and histories of at least one prior spontaneous birth between 16 and 30 weeks' gestation. The results of those examinations were correlated with gestational age at delivery. RESULTS: Among 53 women who had ultrasound examinations before 20 weeks' gestation, those with cervical lengths at or below the tenth percentile for the study population (22 mm, n = 4) or funneling of the internal os (n = 5) were more likely than women without those factors to have spontaneous preterm births within 2 weeks (33% versus 0%, P = .01) or 4 weeks from the ultrasound examination (67% versus 0%, P < .001) or before 35 weeks' gestation (100% versus 19%, P < .001). Short cervical length or funneling between 20-24 and 25-29 weeks was also associated with increased risk of spontaneous preterm birth before 35 weeks' gestation (P < or = .05 and P = .002, respectively) but not with increased risk of spontaneous preterm birth within 2 or 4 weeks of ultrasound examination. CONCLUSION: Women with prior early spontaneous preterm births who have short cervical lengths or funneling of the internal cervical os before 20 weeks' gestation are at increased risk of subsequent spontaneous preterm birth.     

Late pre-term (32 - 36 weeks) birth in a North London hospital.

Most of the complications of pre-term delivery arise in the 1 - 2% of births before 32 weeks' gestation. However, late pre-term birth (32 - 36 weeks' gestation) is still worrying for the mother and clinician. In a retrospective study that compared the management and outcome of 103 singleton pregnancies delivered between 32 and 36 weeks' of gestation with 103 age-matched controls that delivered at term, a short inter-pregnancy interval, early pregnancy bleeding, pre-labour spontaneous rupture of membranes, a history of pre-term delivery and Asian race or single marital status were found to be significant factors. The groups did not differ in parity, BMI, smoking status or history of miscarriages and terminations. Following a logistic regression analysis, the following emerged as risk factors for late pre-term delivery; a history of previous pre-term delivery (OR = 7.2; 95% CI 1.6 - 33.2), a short (<12 months) inter-pregnancy interval (OR = 4.1; 95% CI 2.2 - 7.5), early pregnancy bleeding (OR = 7.6; 95% CI 1.3 - 38.3) and pre-labour spontaneous rupture of membranes (OR = 13.3, 95% CI 3.1 - 55.2).     

Association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth

OBJECTIVE: To determine the association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth. DESIGN: Multicentre prospective cohort study. SETTING: Ten European centres offering prenatal screening for toxoplasmosis. POPULATION: Deliveries after 23 weeks of gestation in 386 women with singleton pregnancies who seroconverted to toxoplasma infection before 20 weeks of gestation. Deliveries after 36 weeks in 234 women who seroconverted at 20 weeks or later, and tested positive before 37 weeks. METHODS: Comparison of infected and uninfected births, adjusted for parity and country of birth. MAIN OUTCOME MEASURES: Differences in gestational age at birth, birthweight and birthweight centile. RESULTS: Infected babies were born or delivered earlier than uninfected babies: the mean difference for seroconverters before 20 weeks was -5.4 days (95% CI: -1.4, -9.4), and at 20 weeks or more, -2.6 days (95% CI: -0.5, -4.7). Congenital infection was associated with an increased risk of preterm delivery when seroconversion occurred before 20 weeks (OR 4.71; 95% CI: 2.03, 10.9). No significant differences were detected for birthweight or birthweight centile. CONCLUSION: Babies with congenital toxoplasmosis were born earlier than uninfected babies but the mechanism leading to shorter length of gestation is unknown. Congenital infection could precipitate early delivery or prompt caesarean section or induction of delivery. We found no evidence for a significant association between congenital toxoplasmosis and reduced birthweight or small for gestational age birth.     

Factores de riesgo del parto pretérmino

Objective

To determine the risk factors for preterm births occurring spontaneously or due to premature rupture of membranes in our environment.

Patients and method

We performed a retrospective case-control study at the Complejo Hospitalario Universitario de Albacete (Spain) that compared 315 pregnant women with preterm labor occurring spontaneously or due to premature rupture of membranes with 315 women selected as controls who delivered at term. The variables were grouped into sociobiological parameters, obstetric history, and characteristics of the current pregnancy.

Results

Previous preterm birth (OR = 3.4; 95% CI, 1.7-6.7), prior abortions (p = 0.002), multiple gestation (OR = 28.1; 95% CI, 6.7-116.8), assisted reproductive technology (ART) (OR = 5.8; 95% CI, 2.3-14.1), hospitalization and tocolytic therapy (OR = 10.8; 95% CI, 4.2-27.7), and cerclage (OR = 5.6; 95% CI, 1.2-25.7) were more frequent in cases. However, when OR were adjusted (aOR) by other variables, the risk for cerclage disappeared (aOR = 2.8; 95% CI, 0.5-14).

Conclusions

Risk factors for preterm birth in our population were a history of preterm birth and abortions, multiple gestation, ART, and hospitalization with tocolytic therapy.     

Advanced maternal age and adverse perinatal outcomes in an Asian population

Objective

To investigate (1) whether there is an increasing trend in the mean maternal age at the birth of the first child and in the group of women giving birth at age 35 or older, and (2) the association between advanced maternal age and adverse perinatal outcomes in an Asian population.

Study design

We conducted a retrospective cohort study involving 39,763 Taiwanese women who delivered after 24 weeks of gestation between July 1990 and December 2003. Multivariable logistic regression was used to adjust for potential confounding variables.

Results

During the study period, the mean maternal age at the birth of the first child increased from 28.0 to 29.7 years, and the proportion of women giving birth at age 35 or older increased from 11.4% to 19.1%. Compared to women aged 20–34 years, women giving birth at age 35 or older carried a nearly 1.5-fold increased risk for pregnancy complications and a 1.6–2.6-fold increased risk for adverse perinatal outcomes. After adjusting for the confounding effects of maternal characteristics and coexisting pregnancy complications, women aged 35–39 years were at increased risk for operative vaginal delivery (adjusted odds ratio [OR] 1.5, 95% confidence interval [CI] 1.2–1.7) and cesarean delivery (adjusted OR 1.6, 95% CI 1.5–1.7), while women aged 40 years and older were at increased risk for preterm delivery (before 37 weeks of gestation) (adjusted OR 1.7, 95% CI 1.3–2.2), operative vaginal delivery (adjusted OR 3.1, 95% CI 2.0–4.6), and cesarean delivery (adjusted OR 2.6, 95% CI 2.2–3.1). In those women who had a completely uncomplicated pregnancy and a normal vaginal delivery, advanced maternal age was still significantly associated with early preterm delivery (before 34 weeks of gestation), a birth weight <1500 g, low Apgar scores, fetal demise, and neonatal death.

Conclusion

In this population of Taiwanese women, there is an increasing trend in the mean maternal age at the birth of the first child. Furthermore, advanced maternal age is independently associated with specific adverse perinatal outcomes.     

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.     

Cervical dimensions and risk of preterm birth: a prospective cohort study

OBJECTIVE: To examine the relation between cervical dilatation and length and the risk of spontaneous preterm birth, including its subtypes preterm labor and preterm premature rupture of membranes (PROM). METHODS: Cervical dimensions assessed by clinical examination were recorded prospectively at 24-29 weeks' gestation in 871 subjects with singleton pregnancies who were followed to delivery. Relative risks (RRs) of preterm birth, preterm labor, and preterm PROM were calculated for clinically distinguishable categories of cervical dilatation and length and for cervical score (length minus dilatation). Regression analysis was used to adjust for confounding. Time to delivery from baseline examination was summarized using survival analysis. RESULTS: There were 73 spontaneous preterm births (8.3%), 46 preterm labors and 27 cases of preterm PROM. All cervical measurements were associated with increased risks of preterm birth, with increasing abnormality more strongly predictive of risk. The adjusted RR for preterm birth with dilatation of at least 0.5 cm was 2.9 (95% confidence interval [CI] 1.2, 7.3); for length of 1.5 cm or less, the RR was 2.1 (95% CI 1.0, 4.5), and for cervical score less than 2.0, the RR was 2.8 (95% CI 1.4, 5.6). The association with cervical measurements was stronger for preterm PROM than for preterm labor, although precision was limited. These measurements had high specificity (93-99%) and low sensitivity (8-20%) for predicting preterm birth. CONCLUSION: In asymptomatic women at 24-29 weeks' gestation, greater cervical dilatation and shorter length were associated with increased risk of spontaneous preterm delivery, particularly preterm PROM.     

Predicting Preterm Birth in Twin Pregnancy: Was the Previous Birth Preterm? A Canadian Experience

ObjectiveMost studies determining risk of preterm birth in a twin pregnancy subsequent to a previous preterm birth are based on linkage studies or small sample size. We wished to identify recurrent risk factors in a cohort of mothers with a twin pregnancy, eliminating all known confounders.MethodsWe conducted a retrospective cohort study of twin births at a tertiary care centre in Montreal, Quebec, between 1994 and 2008, extracting information, including chorionicity, from patient charts.To avoid the effect of confounding factors, we included only women with a preceding singleton pregnancy and excluded twin-to-twin transfusion syndrome, fetal chromosomal/structural anomalies, fetal demise, and preterm iatrogenic delivery for reasons not encountered in both pregnancies. We used multiple regression and sensitivity analyses to determine recurrent risk factors.ResultsOf 1474 twin pregnancies, 576 met the inclusion criteria. Of these, 309 (53.6%) delivered before 37 weeks. Preterm birth in twins was strongly associated with preterm birth of the preceding singleton (adjusted OR 3.23; 95% CI 1.75 to 5.98). The only other risk factors were monochorionic twins (adjusted OR 1.82; 95% CI 1.21 to 2.73) and oldest or youngest maternal ages. Chronic or gestational hypertension, preeclampsia, and insulin-dependent diabetes during the singleton pregnancy did not significantly affect risk.ConclusionPreterm birth in a previous singleton pregnancy was confirmed as an independent risk factor for preterm birth in a subsequent twin pregnancy. This three-fold increase in risk remained stable regardless of year of birth, inclusion/exclusion of pregnancies following assisted reproduction, or defining preterm birth as < 34 or < 37 weeks’ gestational age. Until the advent of optimal preventive strategies, close obstetric surveillance of twin pregnancies is warranted.     

Perinatal outcomes with intrahepatic cholestasis of pregnancy in twin pregnancies

Objective: To describe perinatal outcomes of twin pregnancies complicated by intrahepatic cholestasis of pregnancy (ICP).

Methods: We conducted a retrospective cohort study of women delivered at a large tertiary obstetric center in Shanghai, China from January 2006 to May 2014. Delivery data were abstracted from medical records of all twin gestations delivered at the hospital.

Results: A total of 129/1922(6.7%) twin and 1190/92?273 singleton (1.3%) pregnancies were complicated by ICP. An increased risk of stillbirth among twin pregnancies was observed (3.9% and 0.8% in the ICP and non-ICP groups, respectively; aOR 5.75, 95% CI 2.00–16.6). Stillbirths with ICP and twins occurred between 33 and 35 weeks gestation compared to 36–38 weeks gestation among singletons. ICP in twins was also associated with an increased risk of preterm birth (<37 weeks) with an aOR of 4.17 (95% CI 2.47–7.04) and an aOR of 1.89 (95% CI 1.26–2.85) for delivery <35 weeks. Twin pregnancies complicated by ICP also had increased meconium staining of amniotic fluid and lower birth weight.

Conclusions: Twin pregnancies with ICP have significantly increased risks of adverse perinatal outcomes including stillbirth and preterm birth. Stillbirth occurs at an earlier gestational age in twin gestation compared to singletons, suggesting that earlier scheduled delivery should be considered in these women.     

Obstetric intervention,stillbirth, and preterm birth

Despite widespread recognition that preventing preterm birth is the most important perinatal challenge facing industrialized countries, preterm birth has increased steadily in recent years. This article examines the relation between trends in preterm birth, preterm labor induction/cesarean delivery, stillbirth, and infant mortality. The recent rise in preterm birth in the United States and Canada has been mainly due to increases in mild preterm birth (34-36 weeks). Live births at 34 to 36 weeks' gestation have increased largely as a consequence of increases in preterm induction and preterm cesarean delivery among women at high risk for adverse pregnancy outcomes. Increased obstetric intervention at 34 to 36 weeks' gestation appears to have led to larger-than-expected temporal declines in stillbirth rates at this gestation. Infant mortality rates have declined overall and also among live births at 34 to 36 weeks' gestation. Obstetric intervention at preterm gestation, when indicated, can prevent stillbirth and reduce infant morbidity and mortality despite the increasing rates of preterm delivery.     

Do Maternal Characteristics and Past Pregnancy Experiences Predict Preterm Delivery Among Women Aged 20 to 34?

Objective: To identify key demographic, lifestyle, and medical indicators for preterm births in women aged 20 to 34.Methods: A population-based, case-control study consisting of 987 women aged 20 to 34, who delivered a liveborn singleton infant at <37 weeks’ gestation in Alberta between May 1999 and August 2000. Controls delivered liveborn infant(s) at ≥37 weeks’ gestation. Information was obtained from computer-assisted telephone interviews, and the provincial Physician Notice of Stillbirth/Birth database. Analysis included bivariate and logistic regression techniques.Results: Logistic regression modelling indicated that significant risk factors for preterm delivery included poor past pregnancy outcome (odds ratio [OR] 6.4), poor emotional health (OR 1.8), more than 3 years or less than I year between pregnancies (OR 1.4 and 1.9, respectively), polyhydramnios and oligohydramnios (OR 4.1), bleeding at greater than 20 weeks’ gestation (OR 10.4), malpresentation (OR 2.9), gestational hypertension (OR 2.2), and gestational hypertension with proteinuria (OR 4.4). Women who had fewer than 10 prenatal visits, regardless of attending prenatal classes, were at highest risk of preterm delivery (OR 6.7).Conclusions: In this population of women aged 20 to 34 years, few prenatal visits, poor emotional health prior to pregnancy, and conditions of the current pregnancy were strongly associated with preterm singleton birth.     

New postnatal urinary incontinence: obstetric and other risk factors in primiparae

OBJECTIVE: To identify obstetric and other risk factors for urinary incontinence that occurs during pregnancy or after childbirth. DESIGN: Questionnaire survey of women. SETTING: Maternity units in Aberdeen (Scotland), Birmingham (England) and Dunedin (New Zealand). POPULATION: A total of 3405 primiparous women with singleton births delivered during 1 year. METHODS: Questionnaire responses and obstetric case note data were analysed using multivariate analysis to identify associations with urinary incontinence. MAIN OUTCOME MEASURES: Urinary incontinence at 3 months after delivery first starting in pregnancy or after birth. RESULTS: The prevalence of urinary incontinence was 29%. New incontinence first beginning after delivery was associated with older maternal age (oldest versus youngest group, OR 2.02, 95% CI 1.35-3.02) and method of delivery (caesarean section versus spontaneous vaginal delivery, OR 0.28, 95% CI 0.19-0.41). There were no significant associations with forceps delivery (OR 1.18, 95% CI 0.92-1.51) or vacuum delivery (OR 1.16, 95% CI 0.83-1.63). Incontinence first occurring during pregnancy and still present at 3 months was associated with higher maternal body mass index (BMI>25, OR 1.68, 95% CI 1.16-2.43) and heavier babies (birthweight in top quartile, OR 1.56, 95% CI 1.12-2.19). In these women, caesarean section was associated with less incontinence (OR 0.39, 95% CI 0.27-0.58) but incontinence was not associated with age. CONCLUSIONS: Women have less urinary incontinence after a first delivery by caesarean section whether or not that first starts during pregnancy. Older maternal age was associated with new postnatal incontinence, and higher BMI and heavier babies with incontinence first starting during pregnancy. The effect of further deliveries may modify these findings.     

The effect of loop electrosurgical excision procedure on future pregnancy outcome

OBJECTIVE: To estimate whether the loop electrosurgical excision procedure (LEEP) is associated with an adverse effect on the outcome of subsequent pregnancies. METHODS: A retrospective cohort study was performed. The study group comprised women who had a LEEP in Halifax County between 1992 and 1999 and then had a subsequent singleton pregnancy of greater than 20 weeks of gestation with delivery at the IWK Health Centre in Halifax, Nova Scotia. The comparison group comprised women with no history of cervical surgery who were matched for age, parity, smoking status, and year of delivery. There were 571 women in each group. The primary outcome was rate of preterm delivery at less than 37 weeks of gestation. Secondary outcomes included delivery at less than 34 weeks and various neonatal and maternal outcomes. The effect of specific LEEP characteristics was analyzed separately. RESULTS: Women who had a LEEP were more likely to deliver preterm overall (7.9% versus 2.5%; odds ratio [OR] 3.50, 95% confidence interval [CI] 1.90-6.95; P < .001) and to deliver preterm after premature rupture of membranes (PROM) (3.5% versus 0.9%; OR 4.10, 95% CI 1.48-14.09). The increase in delivery at less than 34 weeks was not statistically significant (1.25% versus 0.36%; OR 3.50, 95% CI 0.85-23.49; P = .12). Women with LEEP also delivered more low birth weight (LBW) infants (5.4% versus 1.9%; OR 3.00, 95% CI 1.52-6.46; P = .003). There were no differences in other neonatal or maternal outcomes. No association was found between the characteristics of the LEEP, including depth, and the rate of preterm delivery. CONCLUSION: Loop electrosurgical excision procedure is associated with an increased risk of overall preterm delivery, preterm delivery after PROM, and LBW infants in subsequent pregnancies at greater than 20 weeks of gestation. Women who are considering future pregnancies should be counseled about these risks during informed consent for LEEP. LEVEL OF EVIDENCE: II-2.     

The preterm prediction study: granulocyte colony-stimulating factor and spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network

OBJECTIVE: Granulocyte colony-stimulating factor is elevated in the amniotic fluid and plasma of women with chorioamnionitis and active preterm labor. We investigated the relationship between plasma granulocyte colony-stimulating factor and subsequent spontaneous preterm birth in pregnant women without symptoms. STUDY DESIGN: We performed a nested case-control study involving 194 women who had a singleton spontaneous preterm birth and 194 matched term control subjects from the patient pool (n = 2929) enrolled in the Preterm Prediction Study. Plasma collected at 24 and 28 weeks' gestation was analyzed for granulocyte colony-stimulating factor, and the results were compared with subsequent spontaneous preterm birth. RESULTS: Compared with term control subjects, women who were delivered of their infants spontaneously at <28 weeks' gestation had increased mean granulocyte colony-stimulating factor values at 24 weeks' gestation (84.7 +/- 38.4 vs 67.7 +/- 28.6 pg/mL; P =.049), and women who were delivered of their infants at <32 weeks' gestation had increased mean plasma granulocyte colony-stimulating factor values at 28 weeks' gestation (80.4 +/- 24.1 vs 55.9 +/- 16.5 pg/mL; P =. 001). At 24 weeks' gestation a granulocyte colony-stimulating factor value >75th percentile in control subjects (approximately 80 pg/mL) was found in 48.9% (23/47) of all women delivered of their infants at <32 weeks' gestation versus 14.9% (7/47) of the term control subjects (adjusted odds ratio, 6.2; 95% confidence interval, 1.8-20. 8). At 28 weeks' gestation a granulocyte colony-stimulating factor value >75th percentile was found in 36.8% (7/19) of women delivered of their infants at <32 weeks' gestation versus 5.3% (1/19) of term control subjects (adjusted odds ratio, 25.7; 95% confidence interval, 1.5-470.4). When measured at 24 or 28 weeks' gestation, granulocyte colony-stimulating factor did not predict spontaneous preterm birth at 32 to 34 weeks' gestation or at 35 to 36 weeks' gestation. CONCLUSION: In pregnant women without symptoms at 24 and 28 weeks' gestation, elevated plasma granulocyte colony-stimulating factor levels are associated with subsequent early (<32 weeks' gestation) spontaneous preterm birth, especially within the next 4 weeks, but not with late spontaneous preterm birth. These data provide further evidence that early spontaneous preterm birth is associated with an inflammatory process that is identifiable by the presence of a cytokine in maternal plasma several weeks before the early spontaneous preterm birth; however, later spontaneous preterm birth is not associated with this process.     

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

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

Association between maternal serum alpha-fetoprotein and adverse outcomes in pregnancies with placenta previa

OBJECTIVE: To determine whether increased maternal serum alpha-fetoprotein (MSAFP) level at 15-20 weeks' gestation is a marker of adverse outcomes in women with placenta previa at delivery. METHODS: We conducted a retrospective cohort study of singleton pregnancies complicated by placenta previa, diagnosed sonographically, and confirmed at delivery. All women had MSAFP screening at 15-20 weeks' gestation and delivered nonanomalous live-born infants at or after 24 weeks' gestation. RESULTS: One hundred seven women with placenta previa delivered during the study. Fourteen (13%, 95% CI 7%, 21%) had MSAFP at least 2.0 multiples of the median (MoM). They were significantly more likely than those with lower MSAFP levels to have one or more of the following outcomes: hospitalization for antepartum bleeding before 30 weeks' gestation (50% versus 15%), delivery before 30 weeks' gestation (29% versus 5%), or preterm delivery for pregnancy-associated hypertension before 34 weeks' gestation (14% versus none). The MSAFP cutoff of 2.0 MoM provided the best combination of sensitivity and specificity for those outcomes, using receiver operating characteristic curves. CONCLUSION: Women with placenta previa who also have high MSAFP levels are at increased risk of bleeding in the early third trimester and preterm birth. We did not find women who required cesarean hysterectomy, including those with placenta accreta, to consistently have elevated MSAFP.     

The preterm prediction study: can low-risk women destined for spontaneous preterm birth be identified?

OBJECTIVE: Half of all preterm births occur in women without clinical risk factors. Our goal was to assess fetal fibronectin assay, Bishop score, and cervical ultrasonography as screening tests to predict which low-risk pregnancies will end in preterm birth. STUDY DESIGN: We performed a secondary analysis of data collected at 22 to 24 weeks' gestation from low-risk subjects enrolled in the Preterm Prediction Study, an observational study of risk factors for preterm birth conducted by the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Analysis was limited to primigravid women and to women who did not have a history of preterm birth or spontaneous pregnancy loss at <20 weeks' gestation. Bishop score (> or =4), fetal fibronectin level (> or =50 ng/mL), and cervical length (< or =25 mm) at 24 weeks' gestation were evaluated alone and in sequence as tests to predict spontaneous delivery before 35 weeks' gestation. RESULTS: Of the 2929 subjects enrolled in the original study, 2197 (1207 primigravid women and 900 low-risk multiparous women) met criteria for this analysis. There were 64 spontaneous births before 35 weeks' gestation (3.04%). All three tests were significantly related to birth before 35 weeks' gestation (high Bishop score: relative risk, 3.6; 95% confidence interval, 2.1-6.3; fetal fibronectin detection: relative risk, 8.2; 95% confidence interval, 4.8-13.9; short cervical length: relative risk, 6.9; 95% confidence interval, 4.3-11.1). However, the sensitivities of the tests alone were low (23.4% for high Bishop score, 23.4% for fetal fibronectin detection, and 39.1% for short cervix), as were the sensitivities for Bishop score followed by cervical ultrasonography (14.1%) and fetal fibronectin assay followed by cervical scan (15.6%). CONCLUSION: In the setting of low-risk pregnancy, fetal fibronectin assay and cervical ultrasonography have low sensitivity for preterm birth before 35 weeks' gestation. Sequential screening with Bishop score or fetal fibronectin assay followed by cervical ultrasonography further decreased sensitivity to only 15% among low-risk women.     

Risk factors for forceps delivery in nulliparous patients

OBJECTIVE: To identify risk factors for forceps delivery during first pregnancy. MATERIALS AND METHODS: A retrospective case-control study was carried out in a tertiary maternity ward between January 2001 and December 2003. A total of 582 nulliparous women, with full-term (>37 weeks gestation), singleton, cephalic pregnancies, who delivered by the vaginal route with or without instrumental assistance were evaluated. RESULTS: The strongest risk factors for forceps delivery were birth weight greater than 4000 g (OR: 6.5; 95% CI: 1.6, 26.9), the occiput posterior position of the fetal head (OR: 5.8; 95% CI: 2.5, 13.8), and epidural analgesia (OR: 7.7; 95% CI: 4.1, 14.7). Other significant risk factors for forceps delivery were age over 35 years (OR: 2.4; 95% CI: 1.1, 5.1), induction of labor (OR: 2.1; 95% CI: 1.4, 3.1), first stage of labor longer than 420 min (OR: 2.3, 95% CI: 1.3,4.2), and a prolonged second stage of labor (OR: 1.6, 95% CI: 1.1, 2.4). CONCLUSION: Age over 35 years and induction of labor are risk factors for forceps delivery at admission. Epidural use, fetal head in occiput posterior position, and birth weight >4000 g are strong intrapartum risk factors for instrumental delivery in nulliparous women.     

Neonatal mortality and morbidity rates in late preterm births compared with births at term

OBJECTIVE: To analyze neonatal mortality and morbidity rates at 34, 35, and 36 weeks of gestation compared with births at term over the past 18 years at our hospital and to estimate the magnitude of increased risk associated with late preterm births compared with births later in gestation. METHODS: We performed a retrospective cohort study of births at our hospital over the past 18 years. The study included all liveborn singleton infants between 34 and 40 weeks of gestation and without anomalies that were delivered to women who received prenatal care in our hospital system. Neonatal outcomes for late preterm births were compared with those for infants delivered at 39 weeks. RESULTS: Late preterm singleton live births constituted approximately 9% of all deliveries at our hospital and accounted for 76% of all preterm births. Late preterm neonatal mortality rates per 1,000 live births were 1.1, 1.5, and 0.5 at 34, 35, and 36 weeks, respectively, compared with 0.2 at 39 weeks (P<.001). Neonatal morbidity was significantly increased at 34, 35, and 36 weeks, including ventilator-treated respiratory distress, transient tachypnea, grades 1 or 2 intraventricular hemorrhage, sepsis work-ups, culture-proven sepsis, phototherapy for hyperbilirubinemia, and intubation in the delivery room. Approximately 80% of late preterm births were attributed to idiopathic preterm labor or ruptured membranes and 20% to obstetric complications. CONCLUSION: Late preterm births are common and associated with significantly increased neonatal mortality and morbidity compared with births at 39 weeks. Preterm labor was the most common cause (45%) for late preterm births. LEVEL OF EVIDENCE: II.