Eugene Chang

Prenatal detection of fetal growth restriction in newborns classified as small for gestational age: correlates and risk of neonatal morbidity.

We examined the rate of detecting small for gestational age (SGA; birth weight < 10%) as intrauterine growth restriction (IUGR) prenatally at four centers and determined risks of composite neonatal morbidity (CNM) and mortality among detected versus undetected (no antenatal diagnosis of IUGR). A multicenter cohort study of 11,487 nonanomalous, singleton live births with sonographic exam before 22 weeks was performed. Of 11,487 births, 8% (n = 929) were SGA that met the inclusion criteria, with 25% of them being prenatally detected. The CNM among SGA births that were prenatally detected as IUGR was higher (23.3%) than undetected SGA (9.7%), but this difference was no longer significant following adjustments for confounding factors. Among preterm births (< 37 weeks), undetected SGA had significantly higher CNM (risk ratio [RR] 10.0, 95% confidence interval [CI] 6.3, 16.1) for deliveries at 24 to 33 weeks and RR 3.0, 95% CI 1.7, 5.4 for 34 to 36 weeks). In summary, only a quarter of SGA births were detected prenatally as IUGR and among preterm SGA, the CNM is significantly higher when SGA births are undetected as IUGR.

Screening for intrauterine growth restriction in uncomplicated pregnancies: Time for action

A randomized clinical trial (RCT) noted that sonographic examination in the third trimester, in conjunction with delivery at term for abnormalities of fetal growth, significantly decreased the likelihood of small-for-gestational-age (SGA) neonates in uncomplicated pregnancies. We identified 15 characteristics of screening tests and attempted to determine if there is evidence to routinely obtain sonographic estimates of fetal weight in the third trimester and decrease rates of SGA. Of the 15 suggested characteristics, currently 10 (67%) are fulfilled, two are uncertain (sonographic examination is cost-effective or reliable), and one (the test must do its job) is possibly valid. Due to the lack of RCTs demonstrating reduction in morbidity, there is potential for lead-time and length bias. To observe a 36% decrease (from 4.1 to 2.6%) decrease in composite perinatal morbidity, 6000 women need to be randomized to at least two sonographic examinations in the third trimester versus routine prenatal care. Such an RCT is warranted and justified.

Isolated intrauterine growth restriction: a survey of Central Association of Obstetricians Gynecologists (CAOG) members

Objective: The objective was to ascertain clinicians’ opinions and current management with isolated (no concomitant morbidity) intrauterine growth restriction (IUGR). Methods: Members of the Central Association of Obstetricians and Gynecologists (CAOG) were surveyed. We considered consensus to be agreement among 90% of the respondents. Results: The response rate was 36% (137/385). Among the 21 questions on the topic, the only consensus was that none of the respondents informed women of the recurrence rate of IUGR. There was variance in what constitutes IUGR as well as practice patterns for detection and management of suboptimal growth. Ten (7%) of the respondents had at least one litigation involving management of IUGR. Responses from 87 general obstetrician-gynecologists varied significantly from that of 33 maternal-fetal medicine (MFM) subspecialists for 48% (10/21) of the survey questions (p < 0.05). Conclusions: There is large practice variation in detection and management of isolated IUGR. This stresses the need for additional studies and a national guideline on its management.

The clinical significance of an estimated fetal weight below the 10th percentile: a comparison of outcomes of <5th vs 5th–9th percentile

BACKGROUND: The association between small‐for‐gestational‐age (birthweight <10th percentile for gestational age) and neonatal morbidity is well established. Yet, there is a paucity of data on the relationship between suspected small for gestational age (sonographic‐estimated fetal weight <10th percentile) at 2 thresholds and subsequent neonatal morbidity. OBJECTIVE: The objective of this study was to determine the relationship between sonographic‐estimated fetal weight <5th percentile vs 5–9th percentile and neonatal morbidity. STUDY DESIGN: This retrospective study involved 5 centers and included nonanomalous, singletons with sonographic‐estimated fetal weight <10th percentile for gestational age who delivered from 2009–2012. Composite neonatal morbidity included respiratory distress syndrome, proven sepsis, intraventricular hemorrhage grade III or IV, necrotizing enterocolitis, thrombocytopenia, seizures, or death. Odd ratios were adjusted for center, maternal age, race, body mass index at first visit, smoking status, use of alcohol, use of drugs, and neonatal gender. RESULTS: Of 834 women with suspected small‐for‐gestational‐age fetuses, 513 (62%) had sonographic‐estimated fetal weight <5th percentile, and 321 (38%) had sonographic‐estimated fetal weight of 5–9th percentile for gestational age. At delivery, 81% of women with a suspected small‐for‐gestational‐age fetus had a confirmed small‐for‐gestational‐age fetus. In the group with a sonographic‐estimated fetal weight <5th percentile, 59% of neonates had birthweight <5th percentile; in the group with a sonographic‐estimated fetal weight 5–9th percentile, 41% had birthweight <5th percentile, and 36% had birthweight at 5–9th percentile. Neonatal intensive care unit admission differed significantly for those fetuses at <5th percentile (29%) compared with those fetuses at 5–9th percentile (15%; P<.001). The composite neonatal morbidity among the sonographic‐estimated fetal weight <5th percentile group was higher than the sonographic‐estimated fetal weight of 5–9th percentile group (31% vs 13%; adjusted odds ratio, 2.41; 95% confidence interval, 1.53–3.80). Similar findings were noted when the analysis was limited to sonographic‐estimated fetal weight within 28 days of delivery (adjusted odds ratio, 2.22; 95% confidence interval, 1.34–3.67). CONCLUSION: Eight of 10 suspected small‐for‐gestational‐age fetuses had birthweight <10th percentile for gestational age; the prediction of actual birthweight was more accurate in the <5th percentile group. Neonates with sonographic‐estimated fetal weight of <5th percentile were more likely to be admitted to the neonatal intensive care unit and have complications than were those neonates with sonographic‐estimated fetal weight of 5–9th percentile.

Uncomplicated Pregnancies and Ultrasounds for Fetal Growth Restriction: A Pilot Randomized Clinical Trial.

Objective The purpose of this multicenter pilot study was to determine the feasibility of randomizing uncomplicated pregnancies (UPs) to have third trimester ultrasonographic exams (USE) versus routine prenatal care (RPNC) to improve the detection of small for gestational age (SGA; birth weight < 10% for GA). Material and Methods At three referral centers, 50 UPs were randomized after gestational diabetes was ruled out. Women needed to screen, consenting, and loss to follow-up was ascertained, as was the detection rate of SGA in the two groups. Results During the study period at the three centers, there were 7,680 births, of which 64% were uncomplicated. Of the 234 women approached for randomization, 36% declined. We recruited 149 women and had follow-up delivery data on 97%. The antenatal detection rate of SGA in the intervention group was 67% (95% confidence intervals 31–91%) and 9% (0.5–43%) in control. Conclusion The pilot study provides feasibility data for a multicenter randomized clinical trial to determine if third trimester USE, compared with RPNC, improves the detection of SGA and composite neonatal morbidity.

Evidence-based medicine in obstetrics: can levels B and C recommendations be elevated to level A recommendations?

In this study, 65% (132/195) of level B/C obstetric recommendations are amenable to randomized clinical trials (RCTs) and seven were identified as most needed. The purpose of the survey was to evaluate levels B and C recommendations in obstetric practice bulletins (PBs) regarding the feasibility of performing RCT to elevate each subject to level A evidence. Eleven geographically dispersed physicians with experience in research reviewed levels B and C recommendations for the ethical and logistical feasibility of performing an RCT. In the 35 obstetric PBs, 195 level B/C recommendations were reviewed. The majority considered 47 (24%) topics unethical for an RCT and thought 16 (11%) did not need an RCT, thus leaving 132 (67%) levels B and C recommendations available for an RCT. Two-thirds of levels B and C recommendations in obstetric PB are amenable to RCTs and potentially becoming level A evidence.