Mode of Delivery in Previable Births.

Preterm birth before 23 weeks of gestation typically results in neonatal death (5% survival). Society for Maternal-Fetal Medicine and American College of Obstetricians and Gynecologists published consensus guidelines recommending cesarean delivery (CD) not be performed for fetal indications between 20 and 226/7 weeks given the lack of proven benefit. We sought to quantify the previable CD rate and identify characteristics associated with previable CD. We performed a population-based retrospective cohort study of all live births in Ohio (2006-2015). Frequency of previable CD was stratified by week of gestation, defined as delivery between 16 and < 23 weeks of gestation. Maternal, obstetric, and neonatal characteristics were compared between women who underwent vaginal delivery versus CD. Multivariable logistic regression estimated the relative influence of maternal and fetal factors on the outcome of CD among previable live births. Of 1,463,506 live births in Ohio during the 10-year study period, 2,865 births (0.2%) occurred during the previable period of 16 to 22 weeks. Nearly 1 in 10 live births at less than 23 weeks was delivered by cesarean (n = 273/2,865), CD rate 9.5% (95% confidence interval, 8.5-10.7). At 16 to 22 weeks of gestation, the CD rates were 0, 5.5, 7.6, 3.5, 5.4, 10.1, and 15.1%, respectively. Factors associated with CD included increasing parity, increasing birth weight, maternal corticosteroid administration, and fetal malpresentation. Previable neonates born by CD were more likely to be admitted to the NICU, receive ventilator support, and more likely to be living at the time of birth certificate filing. Nearly 1 out of 10 births during the previable period was delivered via cesarean. Factors associated with previable CD suggest intent for neonatal interventions, such as NICU admission and supportive therapies. Our findings support that education and adherence with guidelines for care of previable births are a potential area of focus for perinatal quality improvement efforts.

Rossi RM ，DeFranco EA 《-》

Racial disparity in previable birth.

Extremely preterm birth of a live newborn before the limit of viability is rare but contributes uniformly to the infant mortality rate because essentially all cases result in neonatal death. The objective of the study was to quantify racial differences in previable birth and their contribution to infant mortality and to estimate the relative influence of factors associated with live birth occurring before the threshold of viability. This was a population-based retrospective cohort of all live births in Ohio over a 7 year period, 2006-2012. Demographic, pregnancy, and delivery characteristics of previable live births at 16 0/7 to 22 6/7 weeks of gestation were compared with a referent group of live births at 37 0/7 to 42 6/7 weeks. Rates of birth at each week of gestation were compared between black and white mothers, and relative risk ratios were calculated. Logistic regression estimated the relative risk of factors associated with previable birth, with adjustment for concomitant risk factors. Of 1,034,552 live births in Ohio during the study period, 2607 (0.25% of all live births) occurred during the previable period of 16-22 weeks. There is a significant racial disparity in the rate and relative risk of previable birth, with a 3- to 6-fold relative risk increase in black mothers at each week of previable gestational age. The incidence of previable birth for white mothers was 1.8 per 1000 and for black mothers, 6.9 per 1000. Factors most strongly associated with previable birth, presented as adjusted relative risk ratio (95% confidence interval [CI]), were maternal characteristics of black race adjusted relative risk 2.9 (95% CI, 2.6-3.2), age ≥ 35 years 1.3 (95% CI, 1.1-1.6), and unmarried 2.1 (95% CI, 1.8-2.3); fetal characteristics including congenital anomaly, 5.4 (95% CI, 3.4-8.1) and genetic disorder, 5.1 (95% CI, 2.5-10.1); and pregnancy characteristics including prior preterm birth 4.4 (95% CI, 3.7-5.2) and multifetal gestation, twin, 16.9 (95% CI, 14.4-19.8) or triplet, 65.4 (95% CI, 32.9-130.2). The majority, 80%, of previable births (16-22 weeks) were spontaneous in nature, compared with 73% in early preterm births (23-33 weeks), 72% in late preterm births (34-36 weeks), and 65% of term births (37-42 weeks) (P < .001). Previable births constituted approximately 28% of total infant mortalities in white newborns and 45% of infant mortalities in black infants in Ohio during the study period. There is a significant racial disparity in previable preterm births, with black mothers incurring a 3- to 6-fold increased relative risk compared with white mothers, most of which are spontaneous in nature. This may explain much of the racial disparity in infant mortality because all live-born previable preterm births result in death. Focused efforts on the prevention of spontaneous previable preterm birth may help to reduce the racial disparity in infant mortality.

DeFranco EA ，Hall ES ，Muglia LJ 《-》

Maternal Complications Associated With Periviable Birth.

Rossi RM ，DeFranco EA 《-》

Planned home births: the need for additional contraindications.

Planned home births in the United States are associated with fewer interventions but with increased adverse neonatal outcomes such as perinatal and neonatal deaths, neonatal seizures or serious neurologic dysfunction, and low 5-minute Apgar scores. The American College of Obstetricians and Gynecologists' Committee on Obstetric Practice states that, to reduce perinatal death and to improve outcomes at planned home births, strict criteria are necessary to guide the selection of appropriate candidates for planned home birth. The committee lists 3 absolute contraindications for a planned home birth: fetal malpresentation, multiple gestations, and a history of cesarean delivery. The aim of this study was to evaluate whether there are risk factors that should be considered contraindications to planned home births in addition to the 3 that are listed by the American College of Obstetricians and Gynecologists. We conducted a population-based, retrospective cohort study of all term (≥37 weeks gestation), normal weight (≥2500 grams), singleton, nonanomalous births from 2009-2013 using the Centers for Disease Control and Prevention's period-linked birth-infant death files that allowed for identification of intended and unintended home births. We examined neonatal deaths (days 0-27 after birth) across 3 groups (hospital-attended births by certified nurse midwives, hospital-attended births by physicians, and planned home births) for 5 risk factors: 2 of the 3 absolute contraindications to home birth listed by the American College of Obstetricians and Gynecologists (breech presentation and previous cesarean delivery) and 3 additional risk factors (parity [nulliparous and multiparous], maternal age [women <35 and ≥35 years old], and gestational age at delivery [37-40 and ≥41 weeks]). The overall risk of neonatal death was significantly higher in planned home births (12.1 neonatal death/10,000 deliveries; P<.001) compared with hospital births by certified nurse midwives (3.08 neonatal death/10,000 deliveries) or physicians (5.09 neonatal death/10,000 deliveries). Neonatal mortality rates were increased significantly at planned home births, with the following individual risk factors: breech presentation (neonatal mortality rate, 127.52/10.000 births), nulliparous pregnant women (neonatal mortality rate, 22.5/10,000), previous cesarean delivery (18.91/10,000 births), and a gestational age ≥41 weeks (neonatal mortality rate, 17.17/10,000 births). Planned home births with ≥1 of the 5 risk factors had significantly higher neonatal death risks compared with deliveries with none of the risks. Neonatal death risk was further increased when a woman's age of ≥35 years was combined with either a first-time birth or a gestational age of ≥41 weeks. In this study, we show 2 risk factors with significantly increased neonatal mortality rates at planned home births in addition to the 3 factors that are listed by the American College of Obstetricians and Gynecologists. These additional risks factors have neonatal mortality rates that are approaching or exceeding those for planned home birth after cesarean delivery: first-time births and a gestational age of ≥ 41 weeks. Therefore, 2 additional risk factors (first-time births and a gestational age of ≥41 weeks) should be added to the 3 absolute contraindications of planned home births that are listed by the American College of Obstetricians and Gynecologists (previous cesarean delivery, malpresentation, multiple gestations) for a total of 5 contraindications for planned home births.

Grünebaum A ，McCullough LB ，Sapra KJ ，Arabin B ，Chervenak FA ... -  《-》

Contemporary Trends in Cesarean Delivery Utilization for Live Births Between 22 0/7 and 23 6/7 Weeks of Gestation.

Rossi RM ，Hall E ，DeFranco EA 《-》