Osteoprotegerin in pregnant adolescents differs by race and is related to infant birth weight z-score.

Osteoprotegerin (OPG) is involved in the regulation of bone turnover, but little is known about this protein during pregnancy or among neonates. We undertook a prospective longitudinal study to identify relationships between OPG, markers of bone turnover and birth outcomes in 155 pregnant adolescents (13-18 years) and their newborns. Maternal blood samples were collected at mid-gestation and at delivery. Cord blood was obtained at delivery. Serum OPG, estradiol and markers of bone formation (osteocalcin) and resorption (N-telopeptide) were assessed in all samples. Placental OPG expression was assessed in placental tissue obtained at delivery. Bone markers and OPG increased significantly from mid-gestation (26.0 ± 3.4 weeks) to delivery (39.3 ± 2.6 weeks). Neonatal OPG was significantly lower, but bone turnover markers were significantly higher than maternal values at mid-gestation and at parturition (P < 0.001). African-American adolescents had higher concentrations of OPG than Caucasian adolescents at mid-gestation (P = 0.01) and delivery (P = 0.04). Gestational age and estradiol were also predictors of maternal OPG at mid-gestation and delivery. OPG concentrations in cord blood were correlated with maternal OPG concentrations and were negatively associated with infant birth weight z-score (P = 0.02) and ponderal index (P = 0.02). In conclusion, maternal OPG concentrations increased across gestation and were significantly higher than neonatal OPG concentrations. Maternal and neonatal OPG concentrations were not associated with markers of bone turnover or placental OPG expression, but neonatal OPG was inversely associated with neonatal anthropometric measures. Additional research is needed to identify roles of OPG during pregnancy.

Impact of maternal and neonatal iron status on placental transferrin receptor expression in pregnant adolescents.

OBJECTIVE: To elucidate the role of maternal and neonatal iron status on placental transferrin receptor (TfR) expression. STUDY DESIGN AND OUTCOMES: Ninety-two healthy pregnant adolescents (ages 14-18 years) were followed across pregnancy. Maternal iron status (hemoglobin, hematocrit, serum ferritin, TfR, and total body iron) was assessed in mid-gestation (21-25 wks) and at delivery in the mother and neonate. Placental TfR protein expression was assessed by western blot in placental tissue collected at delivery. RESULTS: Placental TfR expression was inversely associated with maternal iron status at mid-gestation (hemoglobin p = 0.046, R(2) = 0.1 and hematocrit p = 0.005, R(2) = 0.24) and at delivery (serum ferritin p = 0.02, R(2) = 0.08 and total body iron p = 0.02, R(2) = 0.07). Mothers with depleted body iron stores had significantly greater placental expression of TfR than mothers with body iron stores greater than zero (p = 0.003). Neonatal iron stores were also inversely associated with the expression of placental TfR (p = 0.04, R(2) = 0.06). Neonates with serum ferritin values ≤ 34 µg/L had significantly greater protein expression of placental TfR compared to neonates with cord serum ferritin values >34 µg/L (p = 0.01). CONCLUSIONS: Expression of placental TfR is associated with both maternal and neonatal iron demands. Increased expression of placental TfR may be an important compensatory mechanism in response to iron deficiency in otherwise healthy pregnant women.

Active management of labor: a meta-analysis of cesarean delivery rates for dystocia in nulliparas.

The objective of this article is to determine through meta-analysis of published literature whether active management of labor lowers the cesarean delivery rate for dystocia in nulliparas. Using MEDLINE and reference citations to 1966, 18 published reports in English on active management of labor were identified. Selection criteria for five selected studies included: tenets of active management followed, detailed description of patient selection and analysis, numerical data on cesarean deliveries for dystocia in nulliparas, and use of a control group. Data on cesarean deliveries performed on nulliparas for dystocia were abstracted onto 2 x 2 tables by both authors independently (one blinded to study authors, journal, institution, and conclusions), and quality ratings independently assessed. Differences were resolved by consensus. Individual odds ratios were calculated, with summary odds ratios and 95 percent confidence intervals determined using the Mantel-Haenszel method. Including the three highest quality studies (two randomized, one nonrandomized), there was a 34 percent decrease in cesarean delivery rates associated with active management (OR 0.66, 95 percent CI 0.54-0.81), without an increase in adverse neonatal outcome (OR for cesarean for non-reassuring fetal heart rate monitoring 0.91, 95 percent CI 0.68-1.22). Active management of labor is associated with a 34 percent decrease in the rate of cesarean delivery for dystocia in nulliparas. Along with the expected subsequent decrease in numbers of candidates for trials of labor, the decline in total cesarean deliveries over the entire population directly or indirectly attributable to active management is 13 percent.

Management of thromboembolic disease associated with pregnancy.

Our objective was to identify practice patterns of members of the Society of Perinatal Obstetricians with regard to the management of thromboembolic disease in pregnant women. We sent survey-questionnaires to members of the Society of Perinatal Obstetricians and requested information on antepartum and postpartum management of four clinical case scenarios. We also requested information on the evaluation of hypercoagulability and on the dosing and monitoring of heparin during pregnancy. We received 515 responses after a single mailing (47%). Most respondents utilize some form of anticoagulation in pregnant women with a history of thromboembolic disease, although there was variation in the duration and intensity of anticoagulation. Nearly all respondents (96%) use full anticoagulation with heparin for pregnant women with prosthetic heart valves. Most respondents evaluate pregnant women for hypercoagulable disorders who present with a thromboembolism or have a history of thromboembolic disease. There is considerable variation with respect to the dosing and monitoring of heparin therapy during pregnancy. Although most SPO members recommend anticoagulation in pregnant women with a history of venous thromboembolism, there is marked variation in the intensity, duration, and monitoring of heparin therapy in pregnant patients. Randomized prospective studies are needed to establish accurate recurrence risks and to evaluate the efficacy of anticoagulation in pregnant women with a history of venous thromboembolism.

Early versus late amniotomy for labor induction: a randomized trial.

OBJECTIVE: Our purpose was to determine the impact of early and late amniotomy on labor induction with continuous oxytocin infusion at term. STUDY DESIGN: A total of 209 women admitted for labor induction were randomized to early or late amniotomy. The early amniotomy group (n = 106) had membranes ruptured as soon as it was deemed safe and feasible. The late amniotomy group (n = 103) had membrane rupture performed at > or = 5 cm dilatation. The first 103 women received a continuous oxytocin infusion with incremental adjustments at 60-minute intervals as required. The next 106 women had adjustments every 30 minutes as required. Statistical analysis was confined to concurrent groups. RESULTS: Early amniotomy was associated with shorter labor (13.3 vs 17.8 hours, p = 0.001), chorioamnionitis (22.6% vs 6.8%, p = 0.002), and significant fetal umbilical cord compression (12.3% vs 2.9%, p = 0.017). The benefit regarding shortening of labor was limited to women having oxytocin increments every 30 minutes as required (13.3 vs 17.8 hours, p = 0.001). Alternatively, the increase in chorioamnionitis was confined to the 60-minute group (39% vs 11%, p < 0.001), which also demonstrated a trend toward increased moderate and severe variable decelerations (19.6% vs 6.4%, p = 0.08). CONCLUSIONS: When a protocol of 60-minute increments in oxytocin infusion rate is desired, amniotomy should be performed late in labor to reduce chorioamnionitis and significant umbilical cord compression. Alternatively, if early amniotomy is necessary, oxytocin should be adjusted every 30 minutes as tolerated.