Christopher S. Croom

Nasal bone length throughout gestation: normal ranges based on 3537 fetal ultrasound measurements

To establish normal ranges for nasal bone length measurements throughout gestation and to compare measurements in two subsets of patients of different race (African‐American vs. Caucasian) to determine whether a different normal range should be used in these populations.

Pregnancy outcome in isolated single umbilical artery.

Our objective was to determine whether the rate of small for gestational age (SGA) infants and adverse perinatal outcome are increased in pregnancies diagnosed with an isolated single umbilical artery (SUA). We compared 297 pregnancies with a SUA diagnosed on routine obstetrical ultrasound with 297 pregnancies with a three-vessel cord control. Pregnancies complicated by major fetal anomalies were excluded. The rate of SGA, fetal death, and neonatal outcomes were compared between the two groups. Data analysis were performed using the T-test and chi-square test. The sample size had 80% power to detect a 50% difference between groups assuming a SGA rate of 20% in the SUA group and 10% in the control, alpha = 0.05. Among the SUA group, in 21 neonates (7.1%) the presence of a SUA could not be confirmed by postnatal examination, and 21 (7.1%) had major congenital anomalies, leaving 255 for final analysis. In the control group, 8 of the 297 (2.7%) had major congenital anomalies, leaving 289 for final analysis. The incidence of SGA neonates was 35 of 255 (13.7%) in the isolated SUA group compared with 38 of 289 (13.1%) in the control group ( P = 0.93). The composite perinatal outcomes (fetal death and/or SGA) were also similar between the groups (16.1% versus 14.5%; P = 0.72). We concluded that pregnancies with isolated SUA have a similar rate of SGA to those with 3VC. When a SUA is identified antenatally, a targeted ultrasound is warranted to rule out associated anomalies. Serial antepartum ultrasound for fetal growth is not necessary in managing pregnancies complicated by isolated SUA.

A Randomized Trial of Micronized Progesterone for the Prevention of Recurrent Preterm Birth

We sought to evaluate the effectiveness of daily oral micronized progesterone (MP) in preventing recurrent spontaneous preterm birth (RSPB) and whether MP increases maternal serum progesterone. We performed a pilot, single-center, randomized, double-blind, placebo-controlled trial in women with a prior preterm birth and current singleton gestation at 16 to 20 weeks ( N = 33). The primary outcome was the rate of RSPB. Subjects were given either daily MP (400 mg) or placebo from 16 to 34 weeks. Serum progesterone was obtained at enrollment and in the late second/early third trimester. Pregnancy outcome data were collected. RSPB occurred in 5/19 (26.3%) in the MP group versus 8/14 (57.1%) in placebo group ( P = 0.15). The mean age at delivery was 37.0 ± 2.7 weeks for the MP group versus 35.9 ± 2.6 weeks for the placebo ( P = 0.3). Mean serum progesterone at 28 weeks was 122.6 ± 61.8 pg/mL for MP group versus 90.1 ± 38.7 pg/mL for placebo ( P = 0.19). MP was associated with a trend toward a reduction in RSPB and an increase in the maternal serum progesterone. Although the primary outcome in this pilot study did not reach statistical significance, the results suggest a favorable trend meriting further investigation.

Serial sonographic growth assessment in pregnancies complicated by an isolated single umbilical artery.

Pregnancies complicated by an isolated single umbilical artery (SUA) are thought to be at increased risk for intrauterine growth restriction (IUGR). The management of these pregnancies often includes serial sonographic assessments of fetal growth. The goal of our study was to test the validity of this assertion. We conducted a longitudinal sonographic assessment of intrauterine fetal growth in pregnancies complicated by a SUA. We included pregnancies where fetal growth was assessed three or more times, and the presence of SUA was repeatedly demonstrated. Pregnancies with fetal anomalies and multiple gestations were excluded. IUGR was defined as an estimated fetal weight (EFW) < or = 10th percentile of the normal ranges established by Hadlock. Between January 1999 and December 2005, we identified 273 pregnancies with SUA, for an overall incidence of 0.48% within the total population of patients examined at our institution. One hundred and thirty-five pregnancies did not meet our inclusion criteria. Of the 138 we analyzed, four pregnancies (2.9%) were found to have EFW < or = 10th percentile. We concluded that the occurrence of IUGR in pregnancies complicated by an isolated SUA is not increased. Serial sonographic assessments of fetal growth do not appear to be indicated in the management of such pregnancies.

Second trimester ultrasound markers of fetal aneuploidy.

Although it is widely accepted that the best time to screen for chromosomal abnormalities is the first trimester, ultrasound evaluation of the fetus in the second trimester has also been shown to be useful for this purpose. A multitude of markers of varying strength has been developed over the past 30 years. In addition, the optimal time to diagnose fetal anomalies with confidence is also the mid second trimester. Therefore, performance of obstetrical ultrasound at this point in gestation continues to be an important component of prenatal care.

OP10.12: Intrauterine growth rate in pregnancies complicated by isolated two-vessel cord

patients who had normal placental parenchyma. The groups were matched for maternal age, gestational age, parity, race, and smoking. Transverse and sagittal scans in real time were used to evaluate the degree and severity of thrombosis. The mean of the two largest lesion diameters was used for severity classification. Results: Mean gestational age at delivery was 39.1 wks (± 1.8) for the control group, 37.9 wks (± 2.8) for mild thrombosis and 35.2 wks (± 5.8) for severe thrombosis, (p < 0.0001). Mean birth weight was 3348 g (± 492) for the control, 3134 g (± 657) for the mild thrombosis and 2524 g (± 1339) for the severe thrombosis group, (p = 0.0005). The presence of IUGR was more frequent in patients with thrombotic lesions: 9.6% in mild thrombosis and 38.4% in severe thrombosis, in comparison to 3.1% in the control group (p = 0.0003; OR = 5.7; p = 0.0151). Pre-eclampsia was also more frequent in patients with thrombosis: control group, 0.0%; the mild group, 7.7%; and severe group, 15.4% (p < 0.0214; OR = 14.3, p = 0.0139). Conclusions: There is a strong association between placental thrombosis and adverse perinatal outcomes. Increased size and/or number of thrombotic lesions is associated with more adverse perinatal outcomes. Ultrasound may be useful in identifying patients with pro-thrombotic abnormalities associated with placental thrombosis.