Moeun Son

Effectiveness of Varicella Vaccine in Children Infected with HIV

Although varicella vaccine is given to clinically stable human immunodeficiency virus (HIV)-infected children, its effectiveness is unknown. We assessed its effectiveness by reviewing the medical records of closely monitored HIV-infected children, including those receiving highly active antiretroviral therapy (HAART) between 1989 and 2007. Varicella immunization and development of varicella or herpes zoster were noted. Effectiveness was calculated by subtracting from 1 the rate ratios for the incidence rates of varicella or herpes zoster in vaccinated versus unvaccinated children. The effectiveness of the vaccine was 82% (95% confidence interval [CI], 24%-99%; P = .01) against varicella and was 100% (95% CI, 67%-100%; P < .001) against herpes zoster. When the analysis was controlled for receipt of HAART, vaccination remained highly protective against herpes zoster.

A universal mid-trimester transvaginal cervical length screening program and its associated reduced preterm birth rate

BACKGROUND Mid-trimester transvaginal cervical length assessment can identify women who are at risk of preterm birth and afford opportunities for preterm birth prevention. However, the incidence of a short cervix is low, and some physicians have questioned whether a universal screening program among women without a previous preterm birth would be beneficial. OBJECTIVE The purpose of this study was to examine whether the introduction of a universal transvaginal cervical length screening program is associated with a reduction in the preterm birth rate. STUDY DESIGN This is a cohort study of women with singleton gestations and without any previous preterm births who underwent an obstetric sonogram at 18-24 weeks of gestation and who had their delivery at a single tertiary institution from January 2007 to January 2014. In July 2011, a program was implemented in which all pregnant women who had a sonogram at 18-24 weeks of gestation were to receive a transvaginal cervical length measurement. The preterm birth rates were compared before and after the implementation of the universal cervical length screening program. Multivariable analysis was used to identify whether the universal cervical length screening program was associated independently with the frequency of preterm birth. The Breslow-Day test for homogeneity was used to assess whether any interaction existed in the association based on parity. RESULTS Of 64,207 eligible women, 46,598 underwent their mid-trimester sonogram before the universal cervical length screening program, and 17,609 underwent a sonogram after implementation of the program. Of the 17,590 women (99.9%) who agreed to cervical length measurement, 157 (0.89%) had a measurement of ≤25 mm. The introduction of the cervical length program was associated with a significant decrease in the frequency of preterm birth at <37 weeks of gestation (6.7% vs 6.0%; adjusted odds ratio, 0.82 [95% confidence interval, 0.76-0.88]), <34 weeks of gestation (1.9% vs 1.7%; adjusted odds ratio, 0.74 [95% confidence interval, 0.64-0.85]), and <32 weeks of gestation (1.1% vs 1.0%; adjusted odds ratio, 0.74 (95% confidence interval, 0.62-0.90]). This reduction in frequency of preterm birth primarily was due to a change in spontaneous (and not medically indicated) preterm births. The effect size for the reduction in preterm birth was similar in nulliparous and multiparous women with previous term births. CONCLUSION The introduction of a universal transvaginal cervical length screening program in women without a history of preterm birth is associated with a reduction in the frequency of preterm birth.

Clinical indication and timing of antenatal corticosteroid administration at a single centre

To determine how well antenatal corticosteroids (ACS) were timed, based on the indication for administration for women delivering preterm.

The association between intrauterine balloon tamponade duration and postpartum hemorrhage outcomes

Background: Intrauterine balloon tamponade is an effective treatment for postpartum hemorrhage when first‐line treatments fail. The optimal duration of intrauterine balloon tamponade for management of postpartum hemorrhage is unclear. Objective: The objective of the study was to determine whether intrauterine balloon tamponade removal >12 hours of duration is associated with postpartum hemorrhage–related clinical outcomes. Study Design: This was a retrospective cohort study of women with postpartum hemorrhage from 2007 through 2014 who underwent intrauterine balloon tamponade. We excluded failures of intrauterine balloon tamponade (intrauterine balloon expulsion with duration <2 hours or if hysterectomy was required prior to planned intrauterine balloon removal). Patients who underwent intrauterine balloon tamponade for 2–12 hours were compared with those who underwent intrauterine balloon tamponade for >12 hours. Examined postpartum hemorrhage–related clinical outcomes included estimated blood loss after intrauterine balloon tamponade placement, blood product transfusion, use of adjuvant measures to control postpartum hemorrhage after intrauterine balloon tamponade (either uterine artery embolization or hysterectomy), and maternal intensive care unit admission. Secondary outcomes examined included postpartum fever and hospital length of stay. Multivariable logistic regression models were used to control for confounding variables. Results: Of 274 eligible women, 206 (75%) underwent intrauterine balloon tamponade for >12 hours and 68 (25%) underwent intrauterine balloon tamponade for 2–12 hours. The median estimated blood loss after intrauterine balloon tamponade placement (190 vs 143 mL, P = .116) as well as the frequencies of blood product transfusion (62.1% vs 51.5%, P = .120), transfusion of ≥4 U of packed red blood cells (17.0% vs 14.7%, P = .659), uterine artery embolization (15.1% vs 16.2%, P = .823), hysterectomy (0.0% vs 1.5%, P = .248), and intensive care unit admission (8.7% vs 7.4%, P = .721), was not statistically different between the groups, and this lack of association persisted in multivariable regressions. Intrauterine balloon tamponade duration >12 hours was associated with a higher frequency of postpartum fever (27% vs 15%, P = .047) and a longer mean hospital length of stay (3.7 vs 3.1 days, P = .002). After adjusting for variables that differed statistically between groups, the difference in length of stay associated with intrauterine balloon tamponade duration was no longer present, but the association between intrauterine balloon tamponade duration >12 hours and postpartum fever persisted (odds ratio, 2.33, 95% confidence interval, 1.07–5.11). Including chorioamnionitis as an independent variable in a post hoc multivariable analysis diminished the association between intrauterine balloon tamponade >12 hours and postpartum fever (adjusted odds ratio, 2.04, 95% confidence interval, 0.92–4.53). Conclusion: There are no significant differences in postpartum hemorrhage–related outcomes associated with intrauterine balloon tamponade duration >12 hours compared with removal 2–12 hours. If ongoing hemorrhage has abated, it is reasonable to consider the removal of an intrauterine balloon by 12 hours after its initial placement.

Preterm premature rupture of membranes and the rate of neonatal sepsis after two courses of antenatal corticosteroids.

OBJECTIVE: To evaluate whether a second antenatal corticosteroid course is associated with an increased risk of neonatal sepsis after preterm premature rupture of membranes (PROM). METHODS: This secondary analysis is a cohort study with data from the Maternal-Fetal Medicine Units study on magnesium for neuroprotection. Women with singleton gestations and preterm PROM were eligible. The primary exposure was one compared with two antenatal corticosteroid courses. The primary outcome, neonatal sepsis, was compared between exposed groups. Patient characteristics were analyzed by &khgr;2 for categorical variables and Student t test or Wilcoxon rank-sum for continuous variables where appropriate. Predictors of neonatal sepsis were analyzed by multivariable logistic regression. RESULTS: One thousand six hundred forty-one patients were eligible. Neonatal sepsis was similar among neonates born to mothers who received one or two antenatal corticosteroid courses (16.2% compared with 17.2%, P=.756, respectively). Adjusting for confounders, the factors associated with neonatal sepsis were length of time from membrane rupture to delivery (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.02–2.26), respiratory distress syndrome (OR 2.11, 95% CI 1.45–3.07), gestational age at delivery in days (OR 0.98, 95% CI 0.95–0.99) and birth weight per 100 g (OR 0.85, 95% CI 0.77–0.94). CONCLUSION: A second maternal antenatal corticosteroid course was not associated with an increased rate neonatal sepsis. LEVEL OF EVIDENCE: II

Is There an Association Between Indication for Intrauterine Balloon Tamponade and Balloon Failure

Objective Determine whether the indication for intrauterine balloon tamponade (IUBT) is associated with failure rates. Study Design Cohort study of women who underwent IUBT for postpartum hemorrhage (PPH) from 2007 to 2014. The indication was categorized as uterine atony or placental‐site bleeding. Primary outcome was IUBT failure, defined as the need for uterine artery embolization or hysterectomy. Secondary outcomes were estimated blood loss (EBL) after balloon placement, transfusion of red blood cells (RBC), transfusion of fresh frozen plasma (FFP) and/or cryoprecipitate, and intensive care unit (ICU) admission. Results 306 women underwent IUBT: 241 (78.8%) for uterine atony and 65 (21.2%) for placental site bleeding. Overall, 67 (21.9%) women experienced IUBT failure. The frequency of failure was similar in those with uterine atony compared with those with placental‐site bleeding (21.2 vs 24.6%, p = 0.55). This finding persisted after adjusting for potential confounders (aOR, 0.97; 95% CI, 0.48‐1.99). Median EBL after balloon placement (190 [interquartile range, 93‐375] vs 195 [interquartile range, 103‐500] mL, p = 0.46), and frequencies of RBC transfusion (62.7 vs 66.2%, p = 0.60), FFP and/or cryoprecipitate transfusion (25.3 vs 33.8%, p = 0.17), and ICU admission (12.4 vs 16.9%, p = 0.35) were also similar. Conclusion IUBT was similarly effective for managing PPH from uterine atony or placental‐site bleeding.

Predicting preterm birth: Cervical length and fetal fibronectin.

Spontaneous preterm birth remains the leading cause of neonatal morbidity and mortality worldwide, and accounts for a significant global health burden. Several obstetric strategies to screen for spontaneous preterm delivery, such as cervical length and fetal fibronectin measurement, have emerged. However, the effectiveness of these strategies relies on their ability to accurately predict those pregnancies at increased risk for spontaneous preterm birth (SPTB). Transvaginal cervical shortening is predictive of preterm birth and when coupled with appropriate preterm birth prevention strategies, has been associated with reductions in SPTB in asymptomatic women with a singleton gestation. The use of qualitative fetal fibronectin may be useful in conjunction with cervical length assessment in women with acute preterm labor symptoms, but data supporting its clinical utility remain limited. As both cervical length and qualitative fetal fibronectin have limited capacity to predict preterm birth, further studies are needed to investigate other potential screening modalities.

Association among Maternal Obesity, Cervical Length, and Preterm Birth.

Objective The objective of this study was to determine if mid‐trimester cervical length is associated with the inverse relationship between maternal body mass index (BMI) at delivery and spontaneous preterm birth (SPTB). Materials and Methods This was a retrospective cohort of women with a singleton pregnancy without prior SPTB who underwent routine transvaginal cervical length assessment between 18 and 24 weeks. Women were categorized into four BMI groups: (1) 18.5 to 24.9, (2) 25 to 29.9, (3) 30 to 34.9, and (4) ≥ 35 kg/m2. Univariable and multivariable analyses were conducted to determine whether BMI group was associated with SPTB at < 37, 34, or 32 weeks independent of the cervical length. Results Of the 18,100 women in this analysis, 43.5% had a BMI ≥ 30. In univariable analysis, increasing BMI group was associated with longer cervical length but not with cervical length < 10th percentile. SPTB at < 37, 35, and 32 weeks was less common among women with higher BMI. In multivariable regression, a higher BMI group was associated with a lower frequency of SPTB at 37 weeks (adjusted odds ratios [aORs] of 0.64, 0.68, and 0.51), at 34 weeks (aORs of 0.53, 0.54, and 0.31) and at 32 weeks (aORs of 0.47, 0.60, and 0.27) for BMI groups 2 to 4, respectively. This association persisted even when cervical length was entered into the model as a covariate. Conclusion Women with a higher BMI group had longer mid‐trimester cervical length, and correspondingly reduced SPTB. However, the decreased risk of SPTB was not associated with cervical length. The reason for the potential protective effect from prematurity is unknown and its mechanisms require further investigation.

The effect of chorionic villus sampling on the fraction of cell-free fetal DNA in maternal plasma

Abstract Objective: This study aims to assess whether the fraction of cell-free fetal DNA (cffDNA) is different at 24 h or 7 days after chorionic villus sampling (CVS), compared to subjects that do not undergo CVS. Methods: Pregnant women undergoing CVS for genetic testing and matched subjects undergoing first trimester combined screening alone were enrolled between 110/7 and 136/7 weeks gestation. The fractions of cffDNA were compared before the procedure, 24 h after and 7 days after between CVS patients and ultrasound-only patients. Results: Forty-five women underwent CVS and 45 had ultrasound alone. The women undergoing CVS were, on average, older (36.8 years versus 28.5 years, p=0.001) and had a higher baseline fraction of cffDNA than women in the comparison group (11.4% versus 9.8%, p=0.033). Both groups had a decrease in the mean fraction of cffDNA after 24 h. After 7 days, the trend of the mean fraction of cffDNA continued to decline in the CVS group but began to trend toward an increase in the ultrasound only group. Conclusions: CVS does not significantly increase the fraction of cell free fetal (placental) DNA in the maternal plasma. A downward trend in cffDNA in maternal plasma is seen at 24 h and 7 days following CVS compared to baseline.

Attempted operative vaginal delivery vs repeat cesarean in the second stage among women undergoing a trial of labor after cesarean delivery

BACKGROUND: It is not well‐characterized whether attempting operative vaginal delivery is a safe and effective alternative among women who undergo a trial of labor after cesarean delivery who are unable to complete second‐stage labor with a spontaneous vaginal delivery. OBJECTIVE: The purpose of this study was to compare maternal and neonatal outcomes that are associated with attempted operative vaginal delivery with those that are associated with second‐stage repeat cesarean delivery without an operative vaginal delivery attempt among women who undergo a trial of labor after cesarean delivery. STUDY DESIGN: This is a retrospective secondary analysis of data from Cesarean Registry of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal‐Fetal Medicine Units Network. Women who underwent a trial of labor after cesarean delivery who were at least 36 weeks gestation were eligible for analysis if they had a live, singleton, nonanomalous gestation in cephalic presentation and reached second‐stage labor (defined as complete cervical dilation) with a fetal station of at least +2. The data for women who had an attempted operative vaginal delivery with either forceps or vacuum were compared with those of women who underwent second stage repeat cesarean delivery without operative vaginal delivery attempt. Outcomes of maternal and neonatal complications were compared between groups with bivariable and multivariable analyses. RESULTS: Of 1230 women whose cases were eligible for analysis, 945 women (76.8%) had an attempted operative vaginal delivery. Of those who underwent attempted operative vaginal delivery, 914 women (96.7%) achieved a vaginal delivery. Women who attempted operative vaginal delivery had a lower mean body mass index (30.4±6.0 vs 31.8±5.9 kg/m2; P=.001) and gestational age (39.5±1.3 vs 39.8±1.2 weeks; P=.012) at delivery and were more likely to be of non‐Hispanic black race (30.0% vs 22.1%; P=.002), to have had a previous vaginal delivery (34.9% vs 20.4%; P<.001), and to have fetal descent greater than +2 station at complete dilation (55.6% vs 16.8%; P<.001) and were less likely to have chorioamnionitis (6.8% vs 19.3%; P<.001). The frequency of endometritis was significantly lower among women who had an attempted operative vaginal delivery compared with those who had repeat cesarean delivery (2.5% vs 9.1%; P<.001). However, other serious maternal or neonatal adverse outcomes were not statistically different between the groups. These findings persisted after adjustment for potential confounders. CONCLUSION: In the setting of a trial of labor after cesarean delivery in the second stage with a fetal station of at least +2, attempted operative vaginal delivery resulted in a vaginal birth after cesarean delivery in most women and was not associated with increased adverse maternal and neonatal outcomes but was associated with a reduced frequency of endometritis compared with repeat cesarean delivery without operative vaginal delivery attempt.