David McKenna

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.

Elective cesarean delivery for women with a previous anal sphincter rupture

OBJECTIVE The purpose of this study was to evaluate elective cesarean delivery for women with a history of anal sphincter rupture. STUDY DESIGN The effectiveness of cesarean delivery in parous women with a previous anal sphincter rupture was determined by decision analysis. The outcomes were excess cesarean deliveries and morbidity and mortality rates per prevented case of anal incontinence. RESULTS We needed 2.3 cesarean deliveries to prevent one case of anal incontinence. A woman who chooses a cesarean delivery has a 11.3% risk of morbidity compared with a 4.2% risk for vaginal delivery (relative risk, 2.7; 95% CI, 2.6-2.8; P<.001). The relative risk for maternal death from a cesarean delivery is 2.6 (95% CI, 1.5-4.5; P<.001). CONCLUSION Continent women with a previous anal sphincter rupture who are delivered vaginally are at high risk for permanent anal incontinence. Cesarean delivery will prevent most cases of anal incontinence, although marginally increasing maternal risk. The increased risk may be justified by the potential benefits. Patients should be counseled on these risks and benefits.

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.

Misoprostol outpatient cervical ripening without subsequent induction of labor: a randomized trial.

OBJECTIVE: To estimate the effect of outpatient administration of a single dose of vaginal misoprostol at term on the interval to delivery in women with unfavorable cervices. METHODS: Randomized, double blind, placebo-controlled trial comparing a single 25-μg outpatient intravaginal dose of misoprostol to placebo in pregnant women with Bishop scores less than 9 at 40 weeks or greater. After placement of the study medication, subjects were permitted to go into spontaneous labor unless an indication for induction developed. Analysis was by intent to treat. The interval to delivery, defined as the time from medication placement to delivery, was compared by Student t test and by survival analysis with the log-rank test. RESULTS: Thirty-three women were randomly assigned to receive misoprostol, and 35 were assigned to receive placebo. The mean interval to delivery was significantly less in the misoprostol group, 4.2 ± 4.1 compared with 6.1 ± 3.6 days, P = .04. The interval to delivery for only the nulliparous patients was significantly less in the misoprostol group, 4.2 ± 4.0 compared with 7.2 ± 3.7 days, P = .02. The survival curves for the interval to delivery were significantly different (P = .04 by log-rank test) with 4.1 days median interval to delivery for misoprostol compared with 9.2 days for placebo. There were no adverse outcomes in either group. CONCLUSION: A single 25-μg outpatient intravaginal dose of misoprostol is effective in decreasing the interval to delivery in women with unfavorable cervices at term. LEVEL OF EVIDENCE: I

Prefrontal space ratio: comparison between trisomy 21 and euploid fetuses in the second trimester

To evaluate a novel ultrasound measurement, the prefrontal space ratio (PFSR), in second‐trimester trisomy 21 and euploid fetuses.

Randomized controlled trial of the effect of 30% versus 80% fraction of inspired oxygen on cesarean delivery surgical site infection.

OBJECTIVE To determine if supplemental perioperative oxygen will reduce surgical site infection (SSI) following cesarean delivery. METHODS This is a randomized, controlled trial evaluating SSI following either 30% or 80% fraction of inspired oxygen (FIO2) during and 2 hours after cesarean delivery. Anesthesia providers administered FIO2 via a high-flow oxygen blender. Subjects, surgeons, and wound evaluation teams were blinded. Serial wound evaluations were performed. Data were analyzed using logistic regression models, Fisher exact test, and t test. RESULTS In all, 179 women were randomized, and 160 subjects were included in the analysis. There were 12/83 (14.5%) SSIs in the control group versus 10/77 (13.0%) in the investigational group (p = 0.82). Caucasian race, increased body mass index, and longer operative time were identified as significant risk factors for infection (p = 0.026, odds ratio 0.283; p = 0.05, odds ratio = 1.058; p = 0.037, odds ratio = 1.038, respectively). CONCLUSION Perioperative oxygenation with 80% Fio2 is not effective in reducing SSI following cesarean delivery.

Vasospasm of the nipple presenting as painful lactation.

BACKGROUND: Breast pain is a common complaint among lactating women. Vasospasm of the nipple should be considered in the differential diagnosis of breast pain, particularly when no other signs of infection or trauma are encountered. This report demonstrates a case of vasospasm successfully treated with nifedipine. CASE: A 26-year-old breastfeeding multipara presented with intermittent episodes of extreme pain associated with blanching of the nipple. The pain subsided upon return of normal color to the nipple. She was able to continue breastfeeding after successful treatment with nifedipine. CONCLUSION: Vasospasm of the nipple causes severe episodic breast pain and may lead to discontinuation of breastfeeding if not appropriately treated. This phenomenon is not well reported in the obstetric and gynecologic literature, although the obstetrician may be the first physician to evaluate a patient with symptoms. Patients with episodic nipple pain and pallor can be successfully treated with nifedipine.

Gender-related differences in fetal heart rate during first trimester

Objective: Many expecting parents wish to ascertain fetal gender early in pregnancy. Our goal was to determine whether fetal heart rate (FHR) of males and females during the first trimester is significantly different. Materials and Methods: From November 1997 to February 2003 we enrolled pregnant women with singleton gestations who underwent obstetric sonography at less than 14 weeks of gestational age. Indications for the sonographic study included first-trimester bleeding, uncertain gestational dating, poor obstetrical history, and aneuploidy screening by nuchal translucency. The sonographic studies were performed by a single sonographer and reviewed by the first author. The FHR was determined by m-mode. All subjects underwent second-trimester sonography at 18.0–24.0 weeks’ gestation by the same team, and fetal gender was recorded. Multiple gestations, miscarriages and pregnancies with uncertain fetal gender were excluded. Sonographically assigned fetal gender was confirmed at delivery. Results: Of the 966 first-trimester studies performed, 477 met the inclusion criteria. Of these, 244 (51%) were female and 233 (49%) were males. There were no statistical differences in mean maternal age, gravidity, parity, and mean gestational age at the time of the first study (9.0 ± 2.3 weeks for female fetuses and 9.0 ± 2.3 weeks for males, p = 0.7). The average female FHR was 151.7 ± 22.7 bpm and male FHR was154.9 ± 22.8 bpm (p = 0.13). Discussion: Contrary to beliefs commonly held by many pregnant women and their families, there are no significant differences between male and female FHR during the first trimester.