Marker chromosomes.

Marker chromosomes are a morphologically heterogeneous group of structurally abnormal chromosomes that pose a significant challenge in prenatal diagnosis. Phenotypes associated with marker chromosomes are highly variable and range from normal to severely abnormal. Clinical outcomes are very difficult to predict when marker chromosomes are detected prenatally. In this review, we outline the classification, etiology, cytogenetic characterization, and clinical consequences of marker chromosomes, as well as practical approaches to prenatal diagnosis and genetic counseling.

Impact of prior bariatric surgery on maternal and fetal outcomes among obese and non-obese mothers.

PURPOSE: To assess the association between bariatric surgery and pregnancy-related outcomes among obese and non-obese women in the state of Florida. METHODS: We conducted a population-based, retrospective cohort analysis using vital records and hospital discharge data in Florida during 2004-2007. Women were categorized based on prior bariatric surgery and pre-pregnancy obesity status. Maternal complications (i.e., anemia, pre-eclampsia, gestational diabetes, chronic hypertension, endocrine disorders, cesarean section, prolonged hospital stay) and fetal morbidities [macrosomia, preterm birth, small for gestational age (SGA)] were the outcomes of interest. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were computed. RESULTS: Mothers with a prior history of bariatric surgery, regardless of obesity status, were more likely to have anemia, chronic hypertension, endocrine disorders, and SGA infants. Classification based on prior history of bariatric surgery and obesity status showed that non-obese mothers with prior bariatric surgery were more likely to have anemia, chronic hypertension, endocrine disorders, and SGA infants, whereas obese mothers without prior bariatric surgery were at greater risk of having gestational diabetes, chronic hypertension, macrosomic infants (AOR = 1.69, 95% CI = 1.65-1.73), and prolonged hospital stay as compared to non-obese mother without prior bariatric surgery. CONCLUSIONS: Although prior bariatric surgery is associated with multiple negative maternal and fetal outcomes, it is protective against infant macrosomia in obese mothers. Our findings support the need for preconception/interconception services tailored for former bariatric surgery patients to improve maternal and feto-infant health outcomes.

Surgical repair of atrial septal defect with severe pulmonary hypertension during pregnancy: a case report with literature review.

We are reporting a case of a 37-year-old pregnant woman with a large secundum atrial septal defect with left-to-right shunt and severe pulmonary hypertension. Her atrial septal defect was undiagnosed before this pregnancy. After carefully considering all the options, we repaired her atrial septal defect with an open heart surgical closure at 20 weeks of gestation. A substantial and consistent reduction in pulmonary arterial pressure after the surgery and subsequent uneventful delivery indicate that surgical repair of atrial septal defects is a viable option that should be considered for such patients.

Maternal alcohol use and medically indicated vs. spontaneous preterm birth outcomes: a population-based study.

BACKGROUND: The aetiology of preterm birth remains poorly understood. The purpose of this study is to investigate if an association exists between prenatal alcohol consumption and preterm birth and to determine if such an association differs by subcategories of preterm birth. METHODS: We employed vital statistics data from the state of Missouri covering the period 1989-2005 (n = 1 221 677 singleton records). The outcome of interest was preterm birth, subclassified into medically indicated and spontaneous phenotypes. Multivariate logistic regression was used to generate adjusted odds ratios, with non-drinking mothers as the referent category. RESULTS: Prenatal alcohol use was associated with elevated risk for preterm birth. The strength of association was more prominent for spontaneous preterm delivery {adjusted odds ratio (AOR) [95% confidence interval (CI)] = 1.34 (1.28-1.41)} than for medically indicated preterm birth [AOR (95% CI) = 1.16 (1.05-1.28)]. The overall risk for drinking-related spontaneous preterm birth increased with incremental rise in the number of drinks consumed per week (P for trend < 0.01). CONCLUSIONS: Prenatal alcohol use is a risk factor for preterm delivery, and especially for spontaneous preterm birth. These findings enhance our understanding of the aetiology of preterm birth and could be utilized in the development of appropriate prevention strategies that will assist in decreasing perinatal mortality and morbidity associated with preterm delivery.

The association of prepregnancy body mass index with pregnancy outcomes in triplet gestations.

The impact of obesity on triplet gestations is poorly understood. In this study, we investigate the association of obesity with birth outcomes in triplets. Triplet births in the state of Missouri from 1989 through 1997 were analyzed. Obesity was defined as maternal prepregnancy body mass index (BMI) >or=30 kg/m(2). We assessed the association between obesity and the following outcomes: stillbirth, preeclampsia, very preterm, small for gestational age (SGA), and a composite adverse birth outcome. We employed logistic regression with further correction for intracluster correlation to obtain adjusted estimates. A total of 667 triplet gestations were analyzed. As compared with normal-weight mothers, the likelihood of stillbirth and preeclampsia was higher among obese mothers (odds ratio[OR] = 3.70; 95% confidence interval [CI] = 1.37 to 9.97 and OR = 3.02; 95% CI = 1.69 to 5.40 respectively). Obese mothers were also about twice as likely to experience at least one of the adverse birth outcomes considered. Obese women with triplet gestations have about four- and threefold elevated risks for stillbirth and preeclampsia as compared with their counterparts with normal weight. This observation may be of utility in the preconceptional counseling of women considering the use of assisted reproductive technology.

Success of programming fetal growth phenotypes among obese women.

OBJECTIVE: To estimate the distribution and success of programmed fetal growth phenotypes among obese women. METHODS: This was a retrospective cohort study using the Missouri maternally linked cohort files (years 1978-1997). Maternal body mass index was classified as Normal (18.5-24.9) (referent group), Obese (class 1, 30.0-34.9; class 2, 35.0-39.9; and extreme or class 3, 40 or more). Fetal growth phenotypes were defined as large for gestational age (LGA), appropriate for gestational age (AGA), and small for gestational age (SGA). We used adjusted odds ratio with correction for intracluster correlation to estimate the risk of neonatal mortality for each fetal growth phenotype. RESULTS: As compared with normal weight mothers, obese gravidas tended to program LGA infants at a higher and increasing rate with ascending obesity severity. The opposite effect was observed with respect to AGA and SGA programming patterns. Neonatal mortality among LGA infants was similar for obese (6.2 in 1,000) and normal (4.9 in 1,000) weight mothers (OR 1.05, 95% confidence interval [CI] 0.75-1.48) and regardless of obesity subtype. By contrast, SGA and AGA infants programmed by obese mothers experienced greater neonatal mortality as compared with those born to normal weight mothers (AGA OR 1.45, 95% CI 1.32-1.59; SGA OR 1.72, 95% CI 1.49-1.98). CONCLUSION: Compared with normal weight mothers, obese women are least successful at programming SGA, less successful at programming AGA, and equally as successful at programming LGA infants. LEVEL OF EVIDENCE: II.

Effect of increased body mass index on the accuracy of estimated fetal weight by sonography in twins.

OBJECTIVE: The purpose of this study was to determine whether increasing body mass index (BMI) decreases the accuracy of sonographic estimations of fetal weight in twin gestations. METHODS: A chart review was conducted, in which 361 charts of patients with twin gestations over a 2-year period were reviewed. A total of 194 patients had sonographic examinations for fetal weight within 6 days of delivery and were included in the analysis. The difference between the sonographically estimated fetal weight was compared with the actual birth weight for each twin and stratified for the patient's BMI. RESULTS: There was a significant increasing trend in mean absolute percent errors with increasing BMIs in both twins (P< .05). The mean absolute percent errors for twin A were 6% for patients with a BMI of less than 25 and 9% for those with a BMI of greater than 30. The mean absolute percent errors for twin B were 6.7% for patients with a BMI of less than 25 and almost 11.7% for those with a BMI of greater than 30. There was a significantly increasing trend in mean absolute differences in grams for both twins with increasing gestational age, with almost a 4-fold increase from less than 28 weeks to greater than 36 weeks in both twins (P< .05). CONCLUSIONS: Increasing maternal obesity decreases the accuracy of sonographically determined fetal weight in twin gestations, particularly for twin B.

Patterns and success of fetal programming among women with low and extremely low pre-pregnancy BMI.

PURPOSE: To estimate the frequency of fetal programming phenotypes among women with low BMI and the success of these programming patterns-to determine if small for gestational age (SGA) is a biologically adaptive mechanism to improve chances for infant survival. METHODS: We examined the frequency of fetal programming phenotypes: SGA, large for gestational age (LGA), and adequate for gestational age (AGA) among 1,063,888 singleton live births from 1978 to 1997. We also estimated the success of fetal programming phenotypes using neonatal death as the primary study outcome. RESULTS: Underweight gravidas with AGA and LGA babies had elevated risk of neonatal mortality when compared to normal weight mothers, while the risk for neonatal mortality among mothers with SGA babies was reduced. CONCLUSIONS: The variation in relative degrees of fetal programming patterns and success observed suggests that underweight mothers are more likely to succeed in programming SGA fetuses rather than any other phenotype.

Prenatal diagnosis of placenta accreta: sonography or magnetic resonance imaging?

OBJECTIVE: The purpose of this study was to compare the accuracy of transabdominal sonography and magnetic resonance imaging (MRI) for prenatal diagnosis of placenta accreta. METHODS: A historical cohort study was undertaken at 3 institutions identifying women at risk for placenta accreta who had undergone both sonography and MRI prenatally. Sonographic and MRI findings were compared with the final diagnosis as determined at delivery and by pathologic examination. RESULTS: Thirty-two patients who had both sonography and MRI prenatally to evaluate for placenta accreta were identified. Of these, 15 had confirmation of placenta accreta at delivery. Sonography correctly identified the presence of placenta accreta in 14 of 15 patients (93% sensitivity; 95% confidence interval [CI], 80%-100%) and the absence of placenta accreta in 12 of 17 patients (71% specificity; 95% CI, 49%-93%). Magnetic resonance imaging correctly identified the presence of placenta accreta in 12 of 15 patients (80% sensitivity; 95% CI, 60%-100%) and the absence of placenta accreta in 11 of 17 patients (65% specificity; 95% CI, 42%-88%). In 7 of 32 cases, sonography and MRI had discordant diagnoses: sonography was correct in 5 cases, and MRI was correct in 2. There was no statistical difference in sensitivity (P = .25) or specificity (P = .5) between sonography and MRI. CONCLUSIONS: Both sonography and MRI have fairly good sensitivity for prenatal diagnosis of placenta accreta; however, specificity does not appear to be as good as reported in other studies. In the case of inconclusive findings with one imaging modality, the other modality may be useful for clarifying the diagnosis.

Evolving trends in 2000 cases of multifetal pregnancy reduction: a single-center experience.

OBJECTIVE: The purpose of this study was to examine changes in multifetal pregnancy reduction (MPR) procedures in 2000 cases and to evaluate evolving trends within the last 1000 MPRs. STUDY DESIGN: Two thousand patients who underwent MPR were identified. Data were collected from a computerized database. Comparisons were made between the first 1000 patients (group 1) and the second 1000 patients (group 2). In addition, changing trends within group 2 were also analyzed. Differences in proportions were evaluated by chi-square test and Fisher's exact test, as appropriate. RESULTS: There was a significant difference in the starting and finishing number of fetuses and a significant increase in the use of chorionic villus sampling before MPR in group 2 vs group 1 (43.7% vs 1.5%; P < .0001). The incidence of monochorionicity was significantly higher in group 2 (5.7%), compared with group 1 (2.1%; P < .001). CONCLUSION: Recent trends in MPR demonstrates significant increases in overall reductions to a singleton fetus, the use of chorionic villus sampling, and the presence of monochorionicity.

The effect of low body mass index on the development of gestational hypertension and preeclampsia.

OBJECTIVES: To evaluate the relationship between low maternal body mass index (BMI) as calculated in the first trimester and the risk of preeclampsia and gestational hypertension. METHODS: Patients enrolled in the First And Second Trimester Evaluation of Risk for aneuploidy (FASTER) trial were grouped into three weight categories: low BMI (BMI <19.8 kg/m2), normal BMI (BMI 19.8 - 26 kg/m2), and overweight BMI (26.1 - 29 kg/m2). The incidences of gestational hypertension and preeclampsia were ascertained for each group. Tests for differences in crude incidence proportions were performed using Chi-square tests. Multiple logistic regression was used to adjust for maternal age, race, parity, obesity, use of assisted reproductive technology (ART), in vitro fertilization (IVF), gestational diabetes, pre-gestational diabetes, cocaine use, and smoking. RESULTS: The proportion of patients having gestational hypertension in the low BMI group was 2.0% compared to 3.2% for normal BMI and 6.0% for overweight BMI (p < 0.0001). Women with low BMI were also less likely to develop preeclampsia, 1.1% vs. 1.9% for normal BMI and 2.8% for overweight BMI (p < 0.0001). CONCLUSIONS: We found that women with low BMI in the first trimester were significantly less likely to develop gestational hypertension or preeclampsia than women with a normal BMI.

Postpartum eclampsia complicated by reversible cerebral herniation.

BACKGROUND: Preeclampsia and eclampsia have been associated with significant morbidity and mortality. Posterior reversible encephalopathy syndrome is a neuroradiologic entity that has been previously reported to occur in patients with preeclampsia and eclampsia. We present, to our knowledge, the first reported case of late postpartum eclampsia complicated by posterior reversible encephalopathy syndrome and reversible cerebral herniation. CASE: A 39-year-old woman (para 1) presented with late postpartum preeclampsia on postpartum day 4. She developed eclampsia and posterior reversible encephalopathy syndrome, which was diagnosed by magnetic resonance imaging. She subsequently developed clinical and radiologic evidence of reversible cerebral herniation. CONCLUSION: Postpartum preeclampsia and eclampsia that is complicated by posterior reversible encephalopathy syndrome can result in cerebral herniation. Neuroradiologic imaging may be a useful adjunctive diagnostic tool in the setting of preeclampsia and eclampsia to predict disease severity.

Abnormal placentation: evidence-based diagnosis and management of placenta previa, placenta accreta, and vasa previa.

Placenta previa, placenta accreta, and vasa previa cause significant maternal and perinatal morbidity and mortality. With the increasing incidence of both cesarean delivery and pregnancies using assisted reproductive technology, these 3 conditions are becoming more common. Advances in grayscale and Doppler ultrasound have facilitated prenatal diagnosis of abnormal placentation to allow the development of multidisciplinary management plans to achieve the best outcomes for mother and baby. We present a comprehensive review of the literature on abnormal placentation including an evidence-based approach to diagnosis and management.

Neonatal outcomes of successful VBAC among obese and super-obese mothers.

OBJECTIVE: We sought to evaluate neonatal morbidity and mortality among women who experienced successful vaginal births after previous cesarean delivery (VBAC) by obesity subtypes. METHODS: Missouri maternally linked cohort data files were utilized. Analyses were restricted to successful singleton VBACs. Main study outcomes were neonatal death and neonatal morbidity. Risk estimates were obtained using logistic and hazards regression modeling. RESULTS: A total of 30,017 singleton births met inclusion criteria. The prevalence of VBAC was 2.3%. The neonatal death rate (per 1000) by maternal obesity subtype was 4.1 for moderate, 3.2 for severe, 4.5 for extreme and 14.3 for super-obese. The overall risk for neonatal morbidity was 56% greater among obese women when compared with normal weight women, with risk estimates increased incrementally with ascending body mass index (BMI) (p for trend < 0.01). CONCLUSION: Infants of obese women undergoing successful VBAC are at elevated risk for neonatal morbidity, and the risk increases progressively with ascending BMI.

Cesarean delivery versus vaginal delivery: impact on survival and morbidity for the breech fetus at the threshold of viability.

OBJECTIVE: To determine if cesarean delivery is associated with improved survival and morbidity in the breech fetus at the threshold of viability. STUDY DESIGN: The Missouri maternally linked cohort data files covering the period 1989 through 2005 were utilized for analysis. All pregnancies with singleton fetuses in the breech presentation delivered between 23(0) and 24(6) weeks gestation and birth weights between 400 and 750 g were included. Logistic regression was used to compare cesarean to vaginal delivery after controlling for maternal demographics and pregnancy complications. RESULTS: A total of 325 breech singletons were analyzed; cesarean deliveries accounted for 46.1% (150) and vaginal deliveries accounted for 53.9% (175). Cesarean delivery was associated with a survival benefit across all birth weights. Morbidity was higher in cesarean compared to vaginal delivery. CONCLUSION: Although cesarean delivery appears to be associated with an increase in survival at the threshold of viability for the breech fetus, there is a concomitant increase in morbidity. Any benefit that cesarean delivery conveys on survival at the threshold of viability should be weighed against the increased maternal morbidity and high overall neonatal morbidity.

Cesarean or vaginal delivery for the breech fetus at the threshold of viability: results from a maternal-fetal medicine specialists survey.

OBJECTIVE: To determine how United States Maternal-Fetal medicine specialists recommend delivery of a breech fetus at the threshold of viability. METHODS: U.S. Society for Maternal-Fetal Medicine (SMFM) members were surveyed about; geographic location, practice type, whether they performed deliveries, definition of threshold for viability, recommendations for delivery of a breech fetus at the threshold of viability, and if the current medical-legal climate had any bearing on their decisions. Chi-Square and Fisher's Exact tests were used for analysis. RESULTS: 510 SMFM members responded to the questionnaire. The highest percentage of respondents stated '23 weeks' (31%) as the cutoff for viability, followed by '24 weeks' (21%) and '23 weeks or 500 g' (10%). Seventy percent recommended cesarean delivery for a breech fetus at the threshold of viability. The majority of respondents based their decision on 'published data' or 'expert opinion', however, 58.6% reported they felt current medical evidence was inadequate to support a recommendation. Fifty-three percent stated their recommendations are affected by medical-legal concerns. CONCLUSION: The majority of U.S. maternal fetal-medicine specialists who responded would recommend cesarean delivery for a breech fetus at the threshold of viability, despite the belief that there is inadequate evidence in the literature to support this recommendation.

Maternal and neonatal outcomes based on the gestational age of midtrimester preterm premature rupture of membranes.

OBJECTIVES: Determine neonatal and maternal outcomes based on the gestational age (GA) that midtrimester preterm premature rupture of membranes (mtPPROM) occurs. STUDY DESIGN: A retrospective chart review was conducted on pregnancies with mtPPROM between 180/7 and 236/7 weeks gestation from January 2000 to December 2007. Antenatal complications, maternal morbidity, and neonatal survival and morbidity were analysed by the specific GA of mtPPROM. Statistical analysis was performed using Chi-square, Fisher's Exact, and Kruskal-Wallis tests. RESULTS: A total of 105 patients met inclusion criteria. There was a trend for longer latency with earlier GA of mtPPROM (p=0.05). Neonatal survival to discharge was 26.6%, with an overall morbidity of 86%. Survival was significantly higher with mtPPROM at 22 0/7-23 6/7 weeks compared to 18 0/7-19 6/7 (p=0.01) and 20 0/7-21 6/7 weeks (p=0.01). There was no difference in neonatal morbidity based on the GA of mtPPROM. CONCLUSIONS: While neonatal survival improves at later GAs of mtPPROM, morbidity continues to be high.

Nulliparity and preterm birth in the era of obesity epidemic.

OBJECTIVE: To assess the impact of obesity on preterm birth among nulliparous women. METHODS: Retrospective cohort study of nulliparous mothers delivering infants in Florida between 2004 and 2007. Women were classified as non-obese (pre-pregnancy body mass index (BMI) <30) or obese (BMI ≥ 30). The main outcomes assessed were preterm birth, very preterm birth and extremely preterm birth. Risk estimates were obtained using logistic regression. Multiparous non-obese mothers were the referent group for all analyses. RESULTS: As compared to multiparous women, nulliparous mothers had an increased risk of very preterm and extremely preterm birth with the highest risk observed for extremely preterm birth (odds ratios (OR) = 1.37, 95% CI = 1.28, 1.47) (p for trend <0.01). Obese nulliparous mothers had an elevated risk of preterm, very preterm and extremely preterm birth, with the risk of extremely preterm birth being the most pronounced (OR=1.97, 95% CI=1.75-2.22) [p for trend <0.05]. The heightened risk associated with obesity among nulliparous women was observed across all racial/ethnic sub-populations, with black nulliparous obese mothers being at greatest risk of all preterm birth-subtypes. CONCLUSIONS: Obesity is a risk marker for preterm, very preterm and extremely preterm birth among first-time mothers and particularly among blacks and Hispanics.

Obesity in older mothers, gestational weight gain, and risk estimates for preterm phenotypes.

OBJECTIVE: To assess whether advanced maternal age modifies the relationship between maternal pregravid weight status, gestational weight gain patterns, and the occurrence of spontaneous preterm birth (SPB) and medically indicated preterm birth (MIPB). METHODS: Retrospective cohort analysis of vital statistics data from the state of Florida for the period 2004 through 2007 comprising 311,422 singleton pregnancies (two age groups: 20-24 years old or younger women and >or=35 years or older women). Mothers were classified into five clusters based on their pre-pregnancy body mass index (BMI) values: non-obese (less than 30), class I obese (30.0or=50.0). RESULTS: MIPB occurred more frequently among older than younger women [11.8% vs. 6.4%, respectively (p<0.0001)) whereas SPB occurred more frequently among younger women [11.3% vs. 10.5%, respectively (p<0.0001)). Maternal obesity increased the risk for MIPB but not for SPB. Regardless of BMI status, the risk of MIPB was elevated among older mothers, particularly among those with suboptimal (<0.23 kg/week) and supraoptimal (>0.68 kg/week) gestational weight gain. A dose-response relationship with increasing gestational weight gain was evident (p<0.01); the greatest risk for MIPB occurred among older mothers with weekly gestational weight gain in excess of 0.79 kg (OR=7.76, 95% CI=5.73-10.5). CONCLUSION: The occurrence of medically indicated preterm birth is positively associated with increased maternal pregravid body weight, older maternal age and extremes of gestational weight gain. Targeted pre- and inter-conception weight management efforts should be particularly encouraged in older mothers.

Prepregnancy obesity and risk of stillbirth in viable twin gestations.

We sought to estimate the impact of prepregnancy obesity on demise of one or both fetuses in twin gestations. We performed a retrospective cohort study using the Missouri maternally linked cohort files (years 1989-2005). Prepregnancy obesity was defined as a BMI >or=30. Outcomes of interest were stillbirth (intrauterine fetal death at >or=20 weeks' gestation) and demise of one (partial loss) or both (complete loss) fetuses, regardless of the cause. We used Cox Proportional Hazards with correction for intracluster correlation to obtain risk estimates. The overall stillbirth rate for twin gestations was 15.5/1,000 (18.4/1,000 vs. 14.5/1,000 in obese and normal weight mothers, respectively; P = 0.02). The rate for complete fetal loss was higher in obese mothers (8.3/1,000 vs. 5.6/1,000; P = 0.01) but was comparable for partial fetal loss (19.1/1,000 for obese vs. 16.3/1,000 for normal weight mothers; P = 0.1). Adjusted estimates confirmed these findings (adjusted hazards ratio (AHR) and 95% confidence interval (CI) = 1.31 (1.02-1.68) for stillbirth; AHR = 1.59; CI = 1.01-2.51) for complete loss; and AHR = 1.21; CI = 0.91-1.62) for partial loss. Subanalysis conducted on stillbirth showed that the risk associated with obesity was only elevated for same-sex (AHR = 1.54; CI = 1.15-2.04) but not opposite-sex twins (0.99; CI = 0.56-1.75). Our findings may find utility in counseling of obese women with twin gestations.