Growth restriction: identifying fetuses at risk.

PURPOSE: Examine risks of intrauterine growth restriction (IUGR) and composite perinatal outcomes with estimated fetal weights (EFW) 10-20th%, and compare outcomes using umbilical artery Doppler (UAD). MATERIALS AND METHODS: Retrospective, cohort evaluating ultrasound (US) EFW 10-20th%, between 2002 and 2012. Cases were identified with EFW % 10-20. Controls, EFW >20th% were obtained for each case, matched by gestational age, and US date. Unadjusted and adjusted logistic regression was used for outcomes. RESULTS: Seven hundred and sixty-seven cases met criteria with matched controls. Fetuses having EFW 10-20th% (GA 33.6 ± 3.7 weeks) had increased IUGR on follow up ultrasound (OR 26.5[10.2-68.7], p < .01), small for gestational age (SGA) (OR 9.2 [6.9-12.3], p < .01), neonatal intensive care unit (NICU) admissions (OR 2.4 [1.6-3.6], p < .01), and composite perinatal morbidity (OR 7.8 [6.0-10.1], p < .01) on adjusted analyses. Abnormal UAD in cases had greater rates of 5 min Apgar <7, NICU admission and composite morbidity (p < .05). CONCLUSIONS: Pregnancies with EFW 10-20th% at the time of initial US are at increased risk for developing IUGR and being SGA at birth, with more NICU admissions and composite perinatal outcomes; abnormal UAD evaluation in cases conveyed further increase in outcomes.

Outcomes With Cerclage Alone Compared With Cerclage Plus 17α-Hydroxyprogesterone Caproate.

OBJECTIVE: To examine the differences in perinatal outcomes among women with a prior preterm birth who received cerclage compared with cerclage plus 17α-hydroxyprogesterone caproate. METHODS: Women with transvaginal cerclage placement and a prior delivery between 16 and 36 weeks of gestation were identified over a 10-year period (July 2002 to May 2012) in this retrospective cohort study. Exclusion criteria were delivery at another institution, abdominal cerclage, multiple gestations, and major fetal anomalies. Maternal demographics, gestational age at cerclage, gestational age at delivery, preterm prelabor rupture of membranes (PROM), and birth weight were compared between women with a cerclage and cerclage plus 17α-hydroxyprogesterone caproate. The primary outcome was delivery at less than 24 weeks of gestation. RESULTS: Of the 411 women who had a cerclage, 260 met inclusion criteria. Of these, 171 received a cerclage alone and 89 received cerclage plus 17α-hydroxyprogesterone caproate. The two groups were not different with respect to maternal demographics and gestational age at cerclage. There was a significant difference among those who received indomethacin at the time of cerclage, betamethasone administration, and history of a loop electrosurgical excision procedure-cold knife cone and cerclage. Delivery at less than 24 weeks of gestation occurred in 6% of women receiving both 17α-hydroxyprogesterone caproate and cerclage compared with 16% in the cerclage only group (odds ratio [OR] 0.31, 95% confidence interval 0.10-0.78, P=.01). In the multivariate analysis controlling for indomethacin use, prior cerclage, and loop electrosurgical excision procedure-cold knife cone there was a 73% reduction in delivery in the combined treatment group compared with cerclage alone (adjusted OR 0.26, P=.02). A multivariant analysis was conducted with correction for indomethacin at the time of cerclage, prior cerclage, and loop electrosurgical excision procedure-cold knife cone and cerclage surgery. Even after controlling for significant variables, there remained a 73% reduction in delivery at less than 24 weeks of gestation in the cerclage plus 17α-hydroxyprogesterone caproate cohort (adjusted OR 0.26, P=.02). CONCLUSION: Women receiving transvaginal cerclage plus 17α-hydroxyprogesterone caproate had a 69% relative reduction in delivery at less than 24 weeks of gestation when compared with women receiving cerclage alone. We found no difference in overall preterm delivery or preterm PROM. In this cohort, compared with cerclage alone, the likelihood of a viable neonate improves with both treatments.

Does increase in birth weight change the normal labor curve?

OBJECTIVE: This study is designed to assess the effect of birth weight on the duration of labor. STUDY DESIGN: Retrospective review of the electronic database created by the Consortium on Safe Labor, reflecting labor and delivery information from 12 clinical centers from 2002 to 2008. Population included all laboring women in the 19 participating hospitals, excluding those with malpresentation, fetal anomalies, elective repeat cesarean, multiple gestations, gestational age less than 34 weeks, and delivery with less than two cervical examinations. Birth weight categories include less than 2,500 g, 2,500 to 3,000 g, 3,000 to 3,500 g, 3,500 to 4,000 g, and greater than 4,000 g. Interval censored regression analysis was used to determine distribution of times for cervical dilation progression in centimeters. RESULTS: A total of 146,904 maternal records were reviewed. In nulliparous, traverse times increased as birth weight increased, both in successful trial of labor and also those who ultimately required cesarean delivery (p < 0.01). In multiparous with successful trial of labor, traverse times increased as birth weight increased from 5 to 8 cm (p < 0.01). From 8 to 10 cm, traverse times increased by birth weight, though this was not statistically significant. CONCLUSION: We have shown that in a large cohort of contemporary laboring women, as birth weight increases, progression in labor is, in fact slower.

Labor patterns in twin gestations.

OBJECTIVE: To compare labor progression in twin vs singleton gestations. STUDY DESIGN: Retrospective review of electronic database created by Consortium on Safe Labor, reflecting labor and delivery information from 12 clinical centers 2002-2008. Women with twin gestations, cephalic presentation of presenting twin, gestational age ≥34 weeks, with ≥2 cervical examinations were included. Exclusion criteria were fetal anomalies or demise. Singleton controls were selected by the same criteria. Categorical variables were analyzed by χ(2); continuous by Student t test. Interval censored regression was used to determine distribution for time of cervical dilation in centimeters, or "traverse times," and controlled for confounding factors. Repeated-measures analysis constructed mean labor curves by parity and number of fetuses. RESULTS: A total of 891 twin gestations were compared with 100,513 singleton controls. Twin gestations were more often older, white or African American, earlier gestational age, increased prepregnancy body mass index, and with lower birthweight. There was no difference in number of prior cesarean deliveries, induction, or augmentation, or epidural use. Median traverse times increased at every centimeter interval in nulliparous twins, in both unadjusted and adjusted analysis (P < .01). A similar pattern was noted for multiparas in both analyses. Labor curves demonstrated a delayed inflection point in the labor pattern for nulliparous and multiparous twin gestations. CONCLUSION: Both nulliparous and multiparous women have slower progression of active phase labor with twins even when controlling for confounding factors.

A comparison of obstetric maneuvers for the acute management of shoulder dystocia.

OBJECTIVE: To assess the efficacy of obstetric maneuvers for resolving shoulder dystocia and the effect that these maneuvers have on neonatal injury when shoulder dystocia occurs. METHODS: Using an electronic database encompassing 206,969 deliveries, we identified all women with a vertex fetus beyond 34 0/7 weeks of gestation who incurred a shoulder dystocia during the process of delivery. Women whose fetuses had a congenital anomaly and women with an antepartum stillbirth were excluded. Medical records of all cases were reviewed by trained abstractors. Cases involving neonatal injury (defined as brachial plexus injury, clavicular or humerus fracture, or hypoxic-ischemic encephalopathy or intrapartum neonatal death attributed to the shoulder dystocia) were compared with those without injury. RESULTS: Among 132,098 women who delivered a term cephalic liveborn fetus vaginally, 2,018 incurred a shoulder dystocia (1.5%), and 101 (5.2%) of these incurred a neonatal injury. Delivery of the posterior shoulder was associated with the highest rate of delivery when compared with other maneuvers (84.4% compared with 24.3-72.0% for other maneuvers; P<.005 to P<.001) and similar rates of neonatal injury (8.4% compared with 6.1-14.0%; P=.23 to P=.7). The total number of maneuvers performed significantly correlated with the rate of neonatal injury (P<.001). CONCLUSION: Delivery of the posterior shoulder should be considered following the McRoberts maneuver and suprapubic pressure in the management of shoulder dystocia. The need for additional maneuvers was associated with higher rates of neonatal injury.

Characteristics associated with severe perineal and cervical lacerations during vaginal delivery.

OBJECTIVE: To characterize potentially modifiable risk factors for third- or fourth-degree perineal lacerations and cervical lacerations in a contemporary U.S. obstetric practice. METHODS: The Consortium on Safe Labor collected electronic medical records from 19 hospitals within 12 institutions (228,668 deliveries from 2002 to 2008). Information on patient characteristics, prenatal complications, labor and delivery data, and maternal and neonatal outcomes were collected. Only women with successful vaginal deliveries of cephalic singletons at 34 weeks of gestation or later were included; we excluded data from sites lacking information about lacerations at delivery and deliveries complicated by shoulder dystocia; 87,267 and 71,170 women were analyzed for third- or fourth-degree and cervical lacerations, respectively. Multivariable logistic regressions were used to adjust for other factors. RESULTS: Third- or fourth-degree lacerations occurred in 2,516 women (2,223 nulliparous [5.8%], 293 [0.6%] multiparous) and cervical lacerations occurred in 536 women (324 nulliparous [1.1%], 212 multiparous [0.5%]). Risks for third- or fourth-degree lacerations included nulliparity (7.2-fold risk), being Asian or Pacific Islander, increasing birth weight, operative vaginal delivery, episiotomy, and longer second stage of labor. Increasing body mass index was associated with fewer lacerations. Risk factors for cervical lacerations included young maternal age, vacuum vaginal delivery, and oxytocin use among multiparous women, and cerclage regardless of parity. CONCLUSION: Our large cohort of women with severe obstetric lacerations reflects contemporary obstetric practices. Nulliparity and episiotomy use are important risk factors for third- or fourth-degree lacerations. Cerclage increases the risk for cervical lacerations. Many identified risk factors may not be modifiable.

Discussion: 'Factor V Leiden mutation' by Kjellberg et al.

In the roundtable that follows, clinicians discuss a study published in this issue of the Journal in light of its methodology, relevance to practice, and implications for future research.

The maternal body mass index: a strong association with delivery route.

OBJECTIVE: We sought to assess body mass index (BMI) effect on cesarean risk during labor. STUDY DESIGN: The Consortium on Safe Labor collected electronic data from 228,668 deliveries. Women with singletons > or = 37 weeks and known BMI at labor admission were analyzed in this cohort study. Regression analysis generated relative risks for cesarean stratifying for parity and prior cesarean while controlling for covariates. RESULTS: Of the 124,389 women, 14.0% had cesareans. Cesareans increased with increasing BMI for nulliparas and multiparas with and without a prior cesarean. Repeat cesareans were performed in > 50% of laboring women with a BMI > 40 kg/m(2). The risk for cesarean increased as BMI increased for all subgroups, P < .001. The risk for cesarean increased by 5%, 2%, and 5% for nulliparas and multiparas with and without a prior cesarean, respectively, for each 1-kg/m(2) increase in BMI. CONCLUSION: Admission BMI is significantly associated with delivery route in term laboring women. Parity and prior cesarean are other important predictors.

Respiratory morbidity in late preterm births.

CONTEXT: Late preterm births (340/7-366/7 weeks) account for an increasing proportion of prematurity-associated short-term morbidities, particularly respiratory, that require specialized care and prolonged neonatal hospital stays. OBJECTIVE: To assess short-term respiratory morbidity in late preterm births compared with term births in a contemporary cohort of deliveries in the United States. DESIGN, SETTING, AND PARTICIPANTS: Retrospective collection of electronic data from 12 institutions (19 hospitals) across the United States on 233,844 deliveries between 2002 and 2008. Charts were abstracted for all neonates with respiratory compromise admitted to a neonatal intensive care unit (NICU), and late preterm births were compared with term births in regard to resuscitation, respiratory support, and respiratory diagnoses. A multivariate logistic regression analysis compared infants at each gestational week, controlling for factors that influence respiratory outcomes. MAIN OUTCOME MEASURES: Respiratory distress syndrome, transient tachypnea of the newborn, pneumonia, respiratory failure, and standard and oscillatory ventilator support. RESULTS: Of 19,334 late preterm births, 7055 (36.5%) were admitted to a NICU and 2032 had respiratory compromise. Of 165,993 term infants, 11,980 (7.2%) were admitted to a NICU, 1874 with respiratory morbidity. The incidence of respiratory distress syndrome was 10.5% (390/3700) for infants born at 34 weeks' gestation vs 0.3% (140/41,764) at 38 weeks. Similarly, incidence of transient tachypnea of the newborn was 6.4% (n = 236) for those born at 34 weeks vs 0.4% (n = 155) at 38 weeks, pneumonia was 1.5% (n = 55) vs 0.1% (n = 62), and respiratory failure was 1.6% (n = 61) vs 0.2% (n = 63). Standard and oscillatory ventilator support had similar patterns. Odds of respiratory distress syndrome decreased with each advancing week of gestation until 38 weeks compared with 39 to 40 weeks (adjusted odds ratio [OR] at 34 weeks, 40.1; 95% confidence interval [CI], 32.0-50.3 and at 38 weeks, 1.1; 95% CI, 0.9-1.4). At 37 weeks, odds of respiratory distress syndrome were greater than at 39 to 40 weeks (adjusted OR, 3.1; 95% CI, 2.5-3.7), but the odds at 38 weeks did not differ from 39 to 40 weeks. Similar patterns were noted for transient tachypnea of the newborn (adjusted OR at 34 weeks, 14.7; 95% CI, 11.7-18.4 and at 38 weeks, 1.0; 95% CI, 0.8-1.2), pneumonia (adjusted OR at 34 weeks, 7.6; 95% CI, 5.2-11.2 and at 38 weeks, 0.9; 95% CI, 0.6-1.2), and respiratory failure (adjusted OR at 34 weeks, 10.5; 95% CI, 6.9-16.1 and at 38 weeks, 1.4; 95% CI, 1.0-1.9). CONCLUSION: In a contemporary cohort, late preterm birth, compared with term delivery, was associated with increased risk of respiratory distress syndrome and other respiratory morbidity.

Effects of magnesium on central arterial compliance in preeclampsia.

OBJECTIVE: The objective of the study was to investigate the effect of MgSO4 infusion on central arterial compliance, using radial artery applanation tonometry in women with preeclampsia. STUDY DESIGN: Seventy women with preeclampsia were prospectively recruited. Radial pulse waveforms were obtained and the aortic waveforms constructed. The arterial compliance surrogates, augmentation pressure (AP) and augmentation index (AIx-75), were derived from the aortic waveform and then compared: prior to MgSO4 (t1), 1 hour after MgSO4 bolus (t2), 4 hours after MgSO4 infusion (t3), and 24 hours after MgSO4 cessation (t4). Statistical analysis was performed using differences of least squared means with Tukey Kramer adjustments. RESULTS: The AP and AIx-75 at t2-t4 were significantly lower compared with t1, with the greatest decrease in arterial stiffness at t3 (P<.05). CONCLUSION: In preeclampsia, MgSO4 improved central arterial compliance. This effect was most exaggerated after 4 hours of infusion and remained 24 hours following MgSO4 completion, suggesting either a sustained arterial compliance effect or resolution of the vasoconstrictive effect of preeclampsia.

Maternal and neonatal outcomes by labor onset type and gestational age.

OBJECTIVE: We sought to determine maternal and neonatal outcomes by labor onset type and gestational age. STUDY DESIGN: We used electronic medical records data from 10 US institutions in the Consortium on Safe Labor on 115,528 deliveries from 2002 through 2008. Deliveries were divided by labor onset type (spontaneous, elective induction, indicated induction, unlabored cesarean). Neonatal and maternal outcomes were calculated by labor onset type and gestational age. RESULTS: Neonatal intensive care unit admissions and sepsis improved with each week of gestational age until 39 weeks (P < .001). After adjusting for complications, elective induction of labor was associated with a lower risk of ventilator use (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.28-0.53), sepsis (OR, 0.36; 95% CI, 0.26-0.49), and neonatal intensive care unit admissions (OR, 0.52; 95% CI, 0.48-0.57) compared to spontaneous labor. The relative risk of hysterectomy at term was 3.21 (95% CI, 1.08-9.54) with elective induction, 1.16 (95% CI, 0.24-5.58) with indicated induction, and 6.57 (95% CI, 1.78-24.30) with cesarean without labor compared to spontaneous labor. CONCLUSION: Some neonatal outcomes improved until 39 weeks. Babies born with elective induction are associated with better neonatal outcomes compared to spontaneous labor. Elective induction may be associated with an increased hysterectomy risk.

Discussion: 'Microcephaly associated with congenital heart defect' by Barbu et al.

In the roundtable that follows, clinicians discuss a study published in this issue of the Journal in light of its methodology, relevance to practice, and implications for future research. Article discussed: Barbu D, Mert I, Kruger M, Bahado-Singh RO. Evidence of fetal central nervous system injury in isolated congenital heart defect: microcephaly at birth. Am J Obstet Gynecol 2009;201:43.e1-7.

Epidemiology and biology of multiple gestations.

Twins have always aroused interest and have been represented throughout history. Conjoined twins have caused even more sensation, the best-known pair being Chang and Eng Bunker, who were born in Thailand in 1811 and inspired the term Siamese twins. Recently, higher-order multiples have caused controversy, and there has been heavy media coverage of large-number deliveries, such as the McCaughey septuplets. In this article, we review the incidence, types, and causes of multiple gestations.

Risk factors for severe perineal tear: can we do better?

Our aim was to investigate the risk factors associated with severe perineal tears defined as either third- or forth-degree tears and, ultimately, find strategies for prevention. We carried a retrospective analysis of a computerized perinatal database, collected prospectively, from a single county hospital between January 1, 1993 and June 30, 1998. Singleton vaginal vertex deliveries were analyzed for potential risk factors using univariate and multiple logistic regression analysis including all two-way interactions. Severe perineal tear occurred in 1905 (8.2%) of 23,244 vaginal deliveries. In the multiple logistic regression analysis, the following factors carried a significantly higher risk for severe laceration: midline episiotomy, primary vaginal delivery, use of pudendal block, forceps deliveries, and birth weight more than 4000 g. The study of interactions demonstrated that mediolateral episiotomy was associated with an increased risk for severe tear only during the first vaginal delivery, but not during a repeat vaginal delivery. Our data suggest that primary vaginal delivery, fetal weight above 4000 g, and the use of pudendal analgesia can help identify in advance patients at highest risk for severe perineal tear. During the delivery of these patients usage of vacuum (instead of forceps) and restricting the use of midline episiotomy might reduce the incidence of severe perineal tear. In cases where episiotomy seems crucial, the use of a mediolateral episiotomy may reduce the likelihood of severe perineal tear.

Glyburide compared to insulin for the treatment of gestational diabetes mellitus: a cost analysis.

OBJECTIVE: To compare the costs associated with glyburide compared to insulin for the treatment of gestational diabetes unresponsive to dietary therapy. STUDY DESIGN: A cost model was designed. The model excluded costs that were identical for both treatment arms, such as the cost of monitoring glucose control. Insulin treatment costs included average wholesale drug costs, wholesale delivery costs (syringes, alcohol pads), and costs of office staff educating patients. Glyburide costs were based on average wholesale drug costs. Downstream costs of potential inpatient evaluation for hypoglycemia were included in the model. RESULTS: In our baseline model, glyburide was significantly less costly than insulin for the treatment of gestational diabetes. The average cost saving per patient based on wholesale drug costs and hospital costs was US$165.84. Actual retail drug savings and hospital charge savings are potentially considerably greater. The strongest determinant of cost savings was medication cost. The model was less sensitive to the one-time costs of inpatient treatment and patient education. CONCLUSION: Glyburide is less costly than insulin for the treatment of gestational diabetes. Cost models can be useful to physicians deciding between two equally efficacious medications, allowing them to incorporate information about their individual practice styles with a complex balance of cost implications.