Myelomeningocele sac associated with worse lower-extremity neurological sequelae: evidence for prenatal neural stretch injury?

OBJECTIVE

To determine whether the presence of a myelomeningocele (MMC) sac and sac size correlate with compromised lower-extremity function in fetuses with open spinal dysraphism.

METHODS

A radiology database search was performed to identify cases of MMC and myeloschisis (MS) diagnosed prenatally in a single center from 2013 to 2017. All cases were evaluated between 18 and 25 weeks. Ultrasound reports were reviewed for talipes and impaired lower-extremity motion. In MMC cases, sac volume was calculated from ultrasound measurements. Magnetic resonance imaging reports were reviewed for hindbrain herniation. The association of presence of a MMC sac and sac size with talipes and impaired lower-extremity motion was assessed. Post-hoc analysis of data from the multicenter Management of Myelomeningocele Study (MOMS) randomized controlled trial was performed to confirm the study findings.

RESULTS

In total, 283 MMC and 121 MS cases were identified. MMC was associated with a lower incidence of hindbrain herniation than was MS (80.9% vs 100%; P < 0.001). Compared with MS cases, MMC cases with hindbrain herniation had a higher rate of talipes (28.4% vs 16.5%, P = 0.02) and of talipes or lower-extremity impairment (34.9% vs 19.0%, P = 0.002). Although there was a higher rate of impaired lower-extremity motion alone in MMC cases with hindbrain herniation than in MS cases, the difference was not statistically significant (6.6% vs 2.5%; P = 0.13). Among MMC cases with hindbrain herniation, mean sac volume was higher in those associated with talipes compared with those without talipes (4.7 ± 4.2 vs 3.0 ± 2.6 mL; P = 0.002). Review of the MOMS data demonstrated similar findings; cases with a sac on baseline imaging had a higher incidence of talipes than did those without a sac (28.2% vs 7.5%; P = 0.007).

CONCLUSIONS

In fetuses with open spinal dysraphism, the presence of a MMC sac was associated with fetal talipes, and this effect was correlated with sac size. The presence of a larger sac in fetuses with open spinal dysraphism may result in additional injury through mechanical stretching of the nerves, suggesting another acquired mechanism of injury to the exposed spinal tissue. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Cervical funneling or intra-amniotic debris and preterm birth in nulliparous women with midtrimester cervical length less than 30 mm

OBJECTIVE

To evaluate whether the presence of cervical funneling or intra-amniotic debris identified in the second trimester is associated with a higher rate of preterm birth (PTB) in asymptomatic nulliparous pregnant women with a midtrimester cervical length (CL) less than 30 mm (i.e. below the 10th percentile).

METHODS

This was a secondary cohort analysis of data from a multicenter trial in nulliparous women between 16 and 22 weeks' gestation with a singleton gestation and CL less than 30 mm on transvaginal ultrasound, randomized to treatment with either 17-alpha-hydroxyprogesterone caproate or placebo. Sonographers were centrally certified in CL measurement, as well as in identification of intra-amniotic debris and cervical funneling. Univariable and multivariable analysis was performed to assess the associations of cervical funneling and intra-amniotic debris with PTB.

RESULTS

Of the 657 women randomized, 112 (17%) had cervical funneling only, 33 (5%) had intra-amniotic debris only and 45 (7%) had both on second-trimester ultrasound. Women with either of these findings had a shorter median CL than those without (21.0 mm vs 26.4 mm; P < 0.001). PTB prior to 37 weeks was more likely in women with cervical funneling (37% vs 21%; odds ratio (OR), 2.2 (95% CI, 1.5-3.3)) or intra-amniotic debris (35% vs 23%; OR, 1.7 (95% CI, 1.1-2.9)). Results were similar for PTB before 34 and before 32 weeks' gestation. After multivariable adjustment that included CL, PTB < 34 and < 32 weeks continued to be associated with the presence of intra-amniotic debris (adjusted OR (aOR), 1.85 (95% CI, 1.00-3.44) and aOR, 2.78 (95% CI, 1.42-5.45), respectively), but not cervical funneling (aOR, 1.17 (95% CI, 0.63-2.17) and aOR, 1.45 (95% CI, 0.71-2.96), respectively).

CONCLUSIONS

Among asymptomatic nulliparous women with midtrimester CL less than 30 mm, the presence of intra-amniotic debris, but not cervical funneling, is associated with an increased risk for PTB before 34 and 32 weeks' gestation, independently of CL. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Correlation between neonatal outcomes of twins depends on the outcome: secondary analysis of twelve randomised controlled trials

OBJECTIVE

To estimate the magnitude of the correlation between neonatal outcomes of twins and demonstrate how this information can be used in the design of randomised controlled trials (RCTs) in women with twin pregnancies.

DESIGN

Secondary analysis of data from 12 RCTs.

SETTING

Obstetric care in multiple countries, 2004-2012.

POPULATION OR SAMPLE

4504 twin pairs born to women who participated in RCTs to assess treatments given during pregnancy.

METHODS

Intraclass correlation coefficients (ICCs) were estimated using log-binomial and linear models.

MAIN OUTCOME MEASURES

Perinatal death, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular haemorrhage, necrotising enterocolitis, sepsis, neonatal intensive care unit admission, birthweight, low birthweight and two composite measures of adverse neonatal outcome.

RESULTS

ICCs for the composite measures of adverse neonatal outcome were all above 0.5, indicating moderate to strong correlation between adverse outcomes of twins. For individual neonatal outcomes, median ICCs across trials ranged from 0.13 to 0.79 depending on the outcome. An example illustrates how ICCs can be used in sample size calculations for RCTs in women with twin pregnancies.

CONCLUSIONS

The correlation between neonatal outcomes of twins varies considerably between outcomes and may be lower than expected. Our ICC estimates can be used for designing and analysing RCTs that recruit women with twin pregnancies and for performing meta-analyses that include such RCTs. Researchers are encouraged to report ICCs for neonatal outcomes in twins in their own RCTs.

TWEETABLE ABSTRACT

Correlation between neonatal outcomes of twins depends on the outcome and may be lower than expected.

The association of beta-2 adrenoceptor genotype with short-cervix mediated preterm birth: a case-control study

OBJECTIVE

To determine whether β2 -adrenoceptor (β2 AR) genotype is associated with shortening of the cervix or with preterm birth (PTB) risk among women with a short cervix in the second trimester.

DESIGN

A case-control ancillary study to a multicentre randomised controlled trial.

SETTING

Fourteen participating centres of the Maternal-Fetal Medicine Units Network of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

POPULATION

Four hundred thirty-nine women, including 315 with short cervix and 124 with normal cervical length.

METHODS

Nulliparous women with cervical length <30 mm upon a 16-22-week transvaginal sonogram and controls frequency-matched for race/ethnicity with cervical lengths ≥40 mm were studied. β2 AR genotype was determined at positions encoding for amino acid residues 16 and 27.

MAIN OUTCOME MEASURES

Genotype distributions were compared between case and control groups. Within the short cervix group, pregnancy outcomes were compared by genotype, with a primary outcome of PTB <37 weeks.

RESULTS

Genotype data were available at position 16 for 433 women and at position 27 for 437. Using a recessive model testing for association between short cervix and genotype, and adjusted for ethnicity, there was no statistical difference between cases and controls for Arg16 homozygosity (OR 0.7, 95% CI 0.4-1.3) or Gln27 homozygosity (OR 0.9, 95% CI 0.3-2.7). Among cases, Arg16 homozygosity was not associated with protection from PTB or spontaneous PTB. Gln27 homozygosity was not associated with PTB risk, although sample size was limited.

CONCLUSIONS

β2 AR genotype does not seem to be associated with short cervical length or with PTB following the second-trimester identification of a short cervix. Influences on PTB associated with β2 AR genotype do not appear to involve a short cervix pathway.

Effectiveness of progestogens to improve perinatal outcome in twin pregnancies: an individual participant data meta-analysis

BACKGROUND

In twin pregnancies, the rates of adverse perinatal outcome and subsequent long-term morbidity are substantial, and mainly result from preterm birth (PTB).

OBJECTIVES

To assess the effectiveness of progestogen treatment in the prevention of neonatal morbidity or PTB in twin pregnancies using individual participant data meta-analysis (IPDMA).

SEARCH STRATEGY

We searched international scientific databases, trial registration websites, and references of identified articles.

SELECTION CRITERIA

Randomised clinical trials (RCTs) of 17-hydroxyprogesterone caproate (17Pc) or vaginally administered natural progesterone, compared with placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Investigators of identified RCTs were asked to share their IPD. The primary outcome was a composite of perinatal mortality and severe neonatal morbidity. Prespecified subgroup analyses were performed for chorionicity, cervical length, and prior spontaneous PTB.

MAIN RESULTS

Thirteen trials included 3768 women and their 7536 babies. Neither 17Pc nor vaginal progesterone reduced the incidence of adverse perinatal outcome (17Pc relative risk, RR 1.1; 95% confidence interval, 95% CI 0.97-1.4, vaginal progesterone RR 0.97; 95% CI 0.77-1.2). In a subgroup of women with a cervical length of ≤25 mm, vaginal progesterone reduced adverse perinatal outcome when cervical length was measured at randomisation (15/56 versus 22/60; RR 0.57; 95% CI 0.47-0.70) or before 24 weeks of gestation (14/52 versus 21/56; RR 0.56; 95% CI 0.42-0.75).

AUTHOR'S CONCLUSIONS

In unselected women with an uncomplicated twin gestation, treatment with progestogens (intramuscular 17Pc or vaginal natural progesterone) does not improve perinatal outcome. Vaginal progesterone may be effective in the reduction of adverse perinatal outcome in women with a cervical length of ≤25 mm; however, further research is warranted to confirm this finding.

Late first-trimester invasive prenatal diagnosis: results of an international randomized trial

OBJECTIVE

To assess, in a randomized trial, the safety and accuracy of amniocentesis and transabdominal chorionic villus sampling (CVS) performed at 11-14 weeks of gestation, given that this time frame is increasingly relevant to early trisomy screening.

METHODS

We compared amniocentesis with CVS from 77 to 104 days of gestation in a randomized trial in a predominantly advanced maternal age population. Before randomization, the feasibility of both procedures was confirmed by ultrasonography, and experienced operators performed sampling under ultrasound guidance; conventional cytogenetic analysis was employed. The primary outcome measure was a composite of fetal loss plus preterm delivery before 28 weeks of gestation in cytogenetically normal pregnancies.

RESULTS

We randomized 3,775 women into 2 groups (1,914 to CVS; 1,861 to amniocentesis), which were comparable at baseline. More than 99.6% had the assigned procedure, and 99.9% were followed through delivery. In contrast to previous thinking, in the cytogenetically normal cohort (n = 3,698), no difference in primary study outcome was observed: 2.1% (95% confidence interval 1.5, 2.8) for CVS and 2.3% (95% confidence interval, 1.7, 3.1) for amniocentesis. However, spontaneous losses before 20 weeks and procedure-related, indicated terminations combined were increased in the amniocentesis group (P =.07, relative risk 1.74). We found a 4-fold increase in the rate of talipes equinovarus after amniocentesis (P =.02) overall and in week 13 (P =.03, relative risk = 4.65), but data were insufficient to determine this risk in week 14.

CONCLUSION

Amniocentesis at 13 weeks carries a significantly increased risk of talipes equinovarus compared with CVS and also suggests an increase in early, unintended pregnancy loss.

LEVEL OF EVIDENCE

I

First-trimester trisomy screening: nuchal translucency measurement training and quality assurance to correct and unify technique

OBJECTIVE

To describe the process of training for measuring nuchal translucency at five clinical centers in North America and to evaluate methods of quality assurance and feedback.

DESIGN

Throughout a period of 18 months, the performance of sonographers in measuring fetal nuchal translucency was monitored using qualitative and quantitative methods of review. After 12 months, different approaches (written and personal feedback) were used to inform sonographers of technical aspects that needed to or could be improved.

RESULTS

On initial qualitative review, discrepancies in judgment from different reviewers coincided with suboptimal magnification, failure to visualize the amniotic membrane and/or use of cross-shaped calipers. At subsequent global review, 13 (29%) images of nuchal translucency measurements were considered unacceptable. Quantitative assessment revealed that, during the first part of the study, the means from four sonographers were significantly smaller and the mean from the fifth sonographer was significantly larger than expected on the basis of findings from The Fetal Medicine Foundation (P < 0.0001). Following feedback, sonographers who underestimated nuchal translucency and who received a written report only did not change measurements overall (P = 0.9759). In contrast, those who received additional intervention showed a marked difference (P < 0.0001).

CONCLUSIONS

Global qualitative review of images from one sonographer may be preferable to assessment of individual aspects of images. Results from global qualitative review correspond well with findings from quantitative analysis, indicating that the latter can be applied for ongoing audit. Observation of divergent results should prompt extensive personal feedback, rather than a written report, to prevent sonographers from settling in their own, inappropriate technique.

Failure of metronidazole to prevent preterm delivery among pregnant women with asymptomatic Trichomonas vaginalis infection

BACKGROUND

Infection with Trichomonas vaginalis during pregnancy has been associated with preterm delivery. It is uncertain whether treatment of asymptomatic trichomoniasis in pregnant women reduces the occurrence of preterm delivery.

METHODS

We screened pregnant women for trichomoniasis by culture of vaginal secretions. We randomly assigned 617 women with asymptomatic trichomoniasis who were 16 to 23 weeks pregnant to receive two 2-g doses of metronidazole (320 women) or placebo (297 women) 48 hours apart. We treated women again with the same two-dose regimen at 24 to 29 weeks of gestation. The primary outcome was delivery before 37 weeks of gestation.

RESULTS

Between randomization and follow-up, trichomoniasis resolved in 249 of 269 women for whom follow-up cultures were available in the metronidazole group (92.6 percent) and 92 of 260 women with follow-up cultures in the placebo group (35.4 percent). Data on the time and characteristics of delivery were available for 315 women in the metronidazole group and 289 women in the placebo group. Delivery occurred before 37 weeks of gestation in 60 women in the metronidazole group (19.0 percent) and 31 women in the placebo group (10.7 percent) (relative risk, 1.8; 95 percent confidence interval, 1.2 to 2.7; P=0.004). The difference was attributable primarily to an increase in preterm delivery resulting from spontaneous preterm labor (10.2 percent vs. 3.5 percent; relative risk, 3.0; 95 percent confidence interval, 1.5 to 5.9).

CONCLUSIONS

Treatment of pregnant women with asymptomatic trichomoniasis does not prevent preterm delivery. Routine screening and treatment of asymptomatic pregnant women for this condition cannot be recommended.

Metronidazole to prevent preterm delivery in pregnant women with asymptomatic bacterial vaginosis. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units

BACKGROUND

Bacterial vaginosis has been associated with preterm birth. In clinical trials, the treatment of bacterial vaginosis in pregnant women who previously had a preterm delivery reduced the risk of recurrence.

METHODS

To determine whether treating women in a general obstetrical population who have asymptomatic bacterial vaginosis (as diagnosed on the basis of vaginal Gram's staining and pH) prevents preterm delivery, we randomly assigned 1953 women who were 16 to less than 24 weeks pregnant to receive two 2-g doses of metronidazole or placebo. The diagnostic studies were repeated and a second treatment was administered to all the women at 24 to less than 30 weeks' gestation. The primary outcome was the rate of delivery before 37 weeks' gestation.

RESULTS

Bacterial vaginosis resolved in 657 of 845 women who had follow-up Gram's staining in the metronidazole group (77.8 percent) and 321 of 859 women in the placebo group (37.4 percent). Data on the time and characteristics of delivery were available for 953 women in the metronidazole group and 966 in the placebo group. Preterm delivery occurred in 116 women in the metronidazole group (12.2 percent) and 121 women in the placebo group (12.5 percent) (relative risk, 1.0; 95 percent confidence interval, 0.8 to 1.2). Treatment did not prevent preterm deliveries that resulted from spontaneous labor (5.1 percent in the metronidazole group vs. 5.7 percent in the placebo group) or spontaneous rupture of the membranes (4.2 percent vs. 3.7 percent), nor did it prevent delivery before 32 weeks (2.3 percent vs. 2.7 percent). Treatment with metronidazole did not reduce the occurrence of preterm labor, intraamniotic or postpartum infections, neonatal sepsis, or admission of the infant to the neonatal intensive care unit.

CONCLUSIONS

The treatment of asymptomatic bacterial vaginosis in pregnant women does not reduce the occurrence of preterm delivery or other adverse perinatal outcomes.

Indicated versus spontaneous preterm delivery: An evaluation of neonatal morbidity among infants weighing </=1000 grams at birth

OBJECTIVE

The aim of the study was to determine whether infants weighing </=1000 g after birth who are born to women who undergo indicated preterm delivery have different neonatal outcomes than do those born as a result of either spontaneous preterm labor or preterm premature rupture of membranes.

STUDY DESIGN

In a 1-year observational study (1992-1993) the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network collected outcome data for 799 infants whose birth weights were </=1000 g. Only singleton infants with gestational age >20 weeks who were not produced as the result of an induced abortion were included. Our analysis was further limited to infants without major congenital anomalies who survived >2 days, were deemed potentially viable by the obstetrician, and would have undergone a cesarean delivery for fetal indications (N = 411). The primary reason for delivery was categorized as indicated delivery, spontaneous preterm labor, or spontaneous preterm premature rupture of membranes. Selected neonatal outcomes were evaluated among infants born to women in each of these groups. Logistic regression analyses were used to control for the effects of other potentially confounding variables.

RESULTS

A total of 156 of the 411 infants were born to women who underwent an indicated preterm delivery, whereas 160 were born after spontaneous preterm labor and 95 were delivered after preterm premature rupture of membranes. Univariate analyses revealed significantly lower incidences of grade III or IV intraventricular hemorrhage, grade III or IV retinopathy of prematurity, and seizure activity among infants born in an indicated preterm delivery than among those born after spontaneous preterm labor or preterm premature rupture of membranes. However, infants of women who underwent indicated preterm delivery had a more advanced mean gestational age at birth than did those born after spontaneous preterm labor or preterm premature rupture of membranes (28 +/- 2 weeks, 26 +/- 2 weeks, and 26 +/- 1 weeks, respectively, P <.001). Multiple logistic regression analysis was therefore used to control for the disparity in gestational age. Multivariate analyses did not confirm the apparent improvement in neonatal outcome in the indicated delivery group.

CONCLUSION

In this population of infants weighing </=1000 g, selected neonatal outcomes did not differ according to birth by indicated preterm delivery, spontaneous preterm labor, or preterm premature rupture of membranes.

Antibiotic therapy for reduction of infant morbidity after preterm premature rupture of the membranes. A randomized controlled trial. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network

CONTEXT

Intrauterine infection is thought to be one cause of preterm premature rupture of the membranes (PPROM). Antibiotic therapy has been shown to prolong pregnancy, but the effect on infant morbidity has been inconsistent.

OBJECTIVE

To determine if antibiotic treatment during expectant management of PPROM will reduce infant morbidity.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

University hospitals of the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

PATIENTS

A total of 614 of 804 eligible gravidas with PPROM between 24 weeks' and 0 days' and 32 weeks' and 0 days' gestation who were considered candidates for pregnancy prolongation and had not received corticosteroids for fetal maturation or antibiotic treatment within 1 week of randomization.

INTERVENTIONS

Intravenous ampicillin (2-g dose every 6 hours) and erythromycin (250-mg dose every 6 hours) for 48 hours followed by oral amoxicillin (250-mg dose every 8 hours) and erythromycin base (333-mg dose every 8 hours) for 5 days vs a matching placebo regimen. Group B streptococcus (GBS) carriers were identified and treated. Tocolysis and corticosteroids were prohibited after randomization.

MAIN OUTCOME MEASURES

The composite primary outcome included pregnancies complicated by at least one of the following: fetal or infant death, respiratory distress, severe intraventricular hemorrhage, stage 2 or 3 necrotizing enterocolitis, or sepsis within 72 hours of birth. These perinatal morbidities were also evaluated individually and pregnancy prolongation was assessed.

RESULTS

In the total study population, the primary outcome (44.1 % vs 52.9%; P=.04), respiratory distress (40.5% vs 48.7%; P=.04), and necrotizing enterocolitis (2.3% vs 5.8%; P=.03) were less frequent with antibiotics. In the GBS-negative cohort, the antibiotic group had less frequent primary outcome (44.5% vs 54.5%; P=.03), respiratory distress (40.8% vs 50.6%; P=.03), overall sepsis (8.4% vs 15.6%; P=.01), pneumonia (2.9% vs 7.0%; P=.04), and other morbidities. Among GBS-negative women, significant pregnancy prolongation was seen with antibiotics (P<.001).

CONCLUSIONS

We recommend that women with expectantly managed PPROM remote from term receive antibiotics to reduce infant morbidity.

Obstetric determinants of neonatal survival: influence of willingness to perform cesarean delivery on survival of extremely low-birth-weight infants. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units

OBJECTIVE

Our purpose was to evaluate the relationship between the approach to obstetric management and survival of extremely low-birth-weight infants.

STUDY DESIGN

In this prospective observational study we evaluated 713 singleton births of infants weighing < or = 1000 gm during 1 year at the 11 tertiary perinatal care centers of the National Institutes of Child Health and Human Development network of maternal-fetal medicine units. Major anomalies, extramural delivery, antepartum stillbirth, induced abortion, and gestational age < 21 weeks were excluded. The obstetrician's opinion of viability and willingness to perform cesarean delivery in the event of fetal distress were ascertained from the medical record or interview when documentation was unclear. Grade 3 and 4 intraventricular hemorrhage, grade 3 and 4 retinopathy of prematurity, necrotizing enterocolitis requiring surgery, oxygen dependence at discharge or 120 days, and seizures were considered serious morbidity. Survival without serious morbidity was considered intact survival. Logistic regression was used to evaluate the influence of the approach to obstetric management, adjusted for birth weight, growth, gender, presentation, and ethnicity.

RESULTS

Willingness to perform cesarean delivery was associated with increased likelihood of both survival (adjusted odds ratio 3.7, 95% confidence interval 2.3 to 6.0) and intact survival (adjusted odds ratio 1.8, 95% confidence interval 1.0 to 3.3). Willingness to intervene for fetal indications appeared to virtually eliminate intrapartum stillbirth and to reduce neonatal mortality. Below 800 gm or 26 weeks, however, willingness to perform cesarean delivery was linked to an increased chance of survival with serious morbidity. Although obstetricians were willing to intervene for fetal indications in most cases by 24 weeks, willingness to perform cesarean delivery was associated with twice the risk for serious morbidity at that gestational age.

CONCLUSIONS

The approach to obstetric management significantly influences the outcome of extremely low-birth-weight infants. Above 800 gm or 26 weeks the obstetrician should usually be willing to perform cesarean delivery for fetal indications. Between 22 and 25 weeks willingness to intervene results in greater likelihood of both intact survival and survival with serious morbidity. In these cases patients and physicians should be aware of the impact of the approach to obstetric management and consider the likelihood of serious morbidity and mortality when formulating plans for delivery.

Prevention of neonatal group B streptococcal infection

The optimal clinical strategy to prevent neonatal group B streptococcal infection has not been established. The Maternal-Fetal Medicine Units Network assessed the feasibility of a randomized clinical trial to compare the effectiveness of two methods of prevention of streptococcal infection. The attack rates of early-onset group B streptococcal disease were estimated for the following: 1) a hypothetical program of universal prenatal screening and selective intrapartum chemoprophylaxis, and 2) a hypothetical program of selective intrapartum chemoprophylaxis based on clinical risk factors. Sample size requirements were calculated for a clinical trial to detect a significant difference in attack rates between the two hypothetical programs. Similar low attack rates using both strategies would require extremely large sample sizes to detect differences between programs. Until a satisfactory, rapid diagnostic test for intrapartum group B streptococcal carrier status is developed and clinical strategies are tested in populations with varying carriage frequencies, institutions will need to individualize their approaches to prevent early-onset neonatal group B streptococcal disease.