Faculty Bibliography

Ultrasound machines are nowadays part of the armamentarium of all modern Labor and Delivery Suites. Due to their portability, these machines are ideal for use in emergencies which can occur at any of the labor and delivery rooms. Many of the emergencies in Labor and Delivery can be life threatening; thus, maternal and fetal safety requires efficient and timely ultrasound evaluation. The purpose of this article is to provide guidelines for quick and efficient use of ultrasound based on both the authors' experience and the published literature.

OBJECTIVE: The objective of the study was to characterize trends in gestational diabetes (GDM) by maternal age, race, and geographic region in the United States. STUDY DESIGN: The National Hospital Discharge Survey, comprised of births in the United States between 1989 and 2004 (weighted n = 58,922,266), was used to examine trends in GDM, based on an International Classification of Diseases, Ninth Revision, Clinical Modification code of 648.8. We examined temporal trends by comparing GDM rates in the earliest (1989-1990) vs most recent (2003-2004) biennial periods. Relative risks, quantifying racial disparity (black vs white) in GDM, were derived through logistic regression models after adjusting for confounders. These analyses were further stratified by maternal age and geographic region. RESULTS: Prevalence rates of GDM increased from 1.9% in 1989-1990 to 4.2% in 2003-2004, a relative increase of 122% (95% confidence interval [CI] 120%, 124%). Among whites, GDM increased from 2.2% in 1989-1990 to 4.2% in 2003-2004 (relative increase of 94% [95% CI 91%, 96%]), and this was largely driven by an increase in the 25-34 year age group. In contrast, the largest relative increase in GDM (260% [95% CI 243%, 279%]) among blacks between 1989-1990 (0.6%) and 2003-2004 (2.1%) occurred to women aged younger than 25 years. The black-white disparity in GDM rates widened markedly among women aged younger than 35 years in the 1997-2004 periods. The largest relative increases were seen in the West (182% [95% CI 177%, 187%]) followed by the South and Northeast. The observed increase in GDM rates in the Northeast, Midwest, and South regions most likely is due to increase in GDM prevalence rates among blacks. CONCLUSION: This study shows that the prevalence rate of GDM in the United States has increased dramatically between 1989 and 2004. The temporal increase and the widening black-white disparity in the rate of GDM deserves further investigation.

OBJECTIVE: To examine the association between changes in prepregnancy body mass index (BMI) between a woman's first two pregnancies and incidence of preeclampsia in the second pregnancy. METHODS: We performed a population-based retrospective cohort analysis using data on women's first two singleton pregnancies (n=136,884) in Missouri (1989-1997). The study was restricted to women without preeclampsia in the first pregnancy. Prepregnancy BMI (kg/m(2)) was categorized as underweight (less than 18.5), normal (18.5-24.9), overweight (25-29.9), and obese (30 or greater). Analyses were adjusted for confounders through multivariable logistic regression. RESULTS: The incidence rate of preeclampsia in the second pregnancy was 2.0%. In comparison with women who were of normal BMI in both pregnancies, the risk for preeclampsia increased when BMI changed between the first two pregnancies from underweight to obese (odds ratio [OR] 5.6, 95% confidence interval [CI] 1.7-18.2), normal to overweight (OR 2.0, 95% CI 1.7-2.3), normal to obese (OR 3.2, 95% CI 2.5-4.2), and overweight to obese (OR 3.7, 95% CI 3.1-4.3). Being obese or overweight in both pregnancies was associated with increased risk of preeclampsia in the second pregnancy. Women who increased their BMI from underweight to normal or overweight between pregnancies had risks of preeclampsia comparable with those with normal BMI in both pregnancies. African-American, but not white, women who had a reduction in BMI from obese or overweight to normal between pregnancies remained at increased risk for preeclampsia. CONCLUSION: Increases in prepregnancy BMI from normal weight to overweight or obese between pregnancies are associated with increased risk of preeclampsia in the subsequent pregnancy. LEVEL OF EVIDENCE: II.

OBJECTIVE: The purpose of this study was to determine the accuracy of our previously published and prospectively validated transcerebellar diameter (TCD) nomogram in the prediction of gestational age (GA) in intrauterine growth-restricted (IUGR) and large fetuses. METHODS: We established a cross-sectional nomogram of TCD in 24,026 well-dated singleton fetuses and prospectively validated the nomogram using 2597 fetuses from a separate population. This nomogram was validated in both IUGR (n = 55) and large (n = 16) fetuses (estimated fetal weight, <10th and >90th percentiles, respectively). The actual GA was subtracted from the TCD-predicted GA in IUGR and large fetuses, and the concordance between the actual and predicted GAs was assessed using the Pearson correlation coefficient. RESULTS: Concordance between the actual and predicted GA based on our previously published singleton TCD nomogram was high for both IUGR and large fetuses (Pearson correlation, r = 0.98 and 0.95, respectively; P < .001). The means (SDs) of actual and predicted GA based on TCD in IUGR fetuses were 24.9 (6.5) and 25.1 (6.3) weeks, respectively. The predicted GA based on TCD in IUGR fetuses was within 3 days in 97.5% in the second trimester and 93.3% in the third trimester. In large fetuses, the difference between the actual and predicted GA based on TCD within 3 days was 100% in both the second and third trimesters. CONCLUSIONS: This study shows that our institution-specific TCD nomogram is reliable and accurate in predicting GA even at extremes of fetal growth.

OBJECTIVE: To test the hypothesis that the presence of preeclampsia, small for gestational age (SGA)-birth, and placental abruption in the first pregnancy confers increased risk in the second pregnancy. METHODS: A retrospective cohort study entailing a case-crossover analysis was performed based on women who had two consecutive singleton live births (n=154,810) between 1989 and 1997 in Missouri. Small for gestational age was defined as infants with birth weight below the 10th centile for gestational age. Risk and recurrence of ischemic placental disease was assessed from fitting logistic regression models after adjusting for several confounders. RESULTS: Preeclampsia in the first pregnancy was associated with significantly increased risk of preeclampsia (odds ratio 7.03, 95% confidence interval 6.51, 7.59), SGA (odds ratio 1.16, 95% confidence interval 1.06, 1.27), and placental abruption (odds ratio 1.90, 95% confidence interval 1.51, 2.38) in the second pregnancy. Similarly, women with SGA and abruption in the first pregnancy were associated with increased risks of all other conditions in the second pregnancy. CONCLUSION: Women with preeclampsia, SGA, and placental abruption in their first pregnancy--conditions that constitute ischemic placental disease--are at substantially increased risk of recurrence of any or all these conditions in their second pregnancy. Although causes of these conditions remain largely speculative, these entities may manifest through a common pathway of ischemic placental disease with significant risk of recurrence.

OBJECTIVE: This study was undertaken to determine the accuracy of our previously published and prospectively validated institution-specific singleton transcerebellar diameter (TCD) nomogram in the prediction of gestational age (GA) in twin pregnancies. We further evaluated whether the prediction of GA in twin gestations using the singleton TCD nomogram differs between monochorionic and dichorionic twins. STUDY DESIGN: In our previously published studies, we retrospectively constructed a cross-sectional nomogram using TCD measurements in 24,026 well-dated, singleton fetuses, and prospectively validated the nomogram using 2,597 singleton fetuses. The current study comprised of 1,278 well-dated twins (19.6% monochorionic) seen in our ultrasound unit between August 1994 and May 2003, and the singleton TCD nomogram was validated in these twin gestations. The actual GA was subtracted from the GA predicted by the TCD nomogram and the concordance between actual and predicted GAs was assessed on the basis of the Pearson's correlation coefficient (r). This was performed separately for monochorionic and dichorionic twins. RESULTS: Concordance between the actual and predicted twin TCD measurements based on our previously published singleton TCD nomogram was high (Pearson's correlation, r = 0.95, P < .0001). Between 16 and 23 weeks' gestation, the predicted mean GA was within 6 days of actual GA. Between 24 and 30 weeks, the predicted mean GA was within 3 days, and at 32 weeks or more, the predicted mean GA was within 5 days of the actual GA. Prediction of GA based on the singleton TCD nomogram was equally accurate in both monochorionic and dichorionic twin gestations (P = .686). CONCLUSION: This study demonstrates that our previously validated singleton TCD nomogram is reliable and accurate in twins irrespective of placental chorionicity.