Incidence, Intrapartum Risk Factors, and Prognosis of Neonatal Hypoxic-Ischemic Encephalopathy Among Infants Born at 35 Weeks Gestation or More.

INTRODUCTION: Neonatal hypoxic-ischemic encephalopathy (HIE) is associated with neonatal mortality, acute neurological injury, and long-term neurodevelopmental disabilities; however, the association between intrapartum factors and HIE remains unclear. METHODS: This population-based cohort study used linked obstetrical and newborn data derived from the Nova Scotia Atlee Perinatal Database (NSAPD, 1988-2015) and the AC Allen Perinatal Follow-Up Program Database (2006-2015) for all pregnancies with live, non-anomalous newborns ≥35 weeks gestation, not delivered by pre-labour cesarean section. Temporal trends in HIE incidence were described, and logistic regression estimated odds ratios (OR) with 95% confidence intervals (CI) for the association of intrapartum factors with HIE. RESULTS: The NSAPD identified 227 HIE cases in the population of 226 711 deliveries from 1988 to 2015. Women with clinical chorioamnionitis in labour (OR 8.0; 95% CI 3.9-16), emergency cesarean delivery (OR 10; 95% CI 7.6-14), shoulder dystocia (OR 3.5; 95% CI 2.1-5.7), placental abruption (OR 18; 95% CI 11-29), and cord prolapse (OR 30; 95% CI 15-61) were more likely to have newborns with HIE. Two-thirds of newborns with HIE had an abnormal intrapartum fetal heart rate tracing. The mortality rate among infants with HIE was 27% by 3 years of age. Neurodevelopmental outcomes in the surviving infants were normal in 43% and showed severe developmental delay in 40%. CONCLUSION: Overall, the rate of HIE was low in infants born at ≥35 weeks gestation. The identification of associated intrapartum factors should promote increased surveillance in these clinical situations and emphasize the importance of careful management to optimize newborn outcomes.

Operative vaginal delivery - An historical perspective.

This chapter will cover the evolution of forceps and vacuum-assisted delivery of the foetus in cephalic presentation. The options available before the development of obstetric forceps are briefly reviewed. The invention of the forceps in the early 17th century was followed by their evolution over four centuries with the introduction of the pelvic curve, axis-traction and rotational forceps. The phase of prophylactic forceps delivery will be discussed. The development of vacuum-assisted delivery has evolved over the past 150 years. However, in practical terms, the modern era of vacuum-assisted delivery began with Tage Malmström's vacuum extractor in the early 1950s. The evolution of the modern vacuum extractor with metal, soft and hard plastic cups will be reviewed.

Type of Labour in the First Pregnancy and Cumulative Perinatal Morbidity.

OBJECTIVE: To estimate cumulative perinatal morbidity among infants delivered at term, according to the type of labour in the first pregnancy, when the first pregnancy was low risk. METHODS: In a 26-year population-based cohort study (1988-2013) using the Nova Scotia Atlee Perinatal Database, we identified the type of labour in successive pregnancies in low-risk, nulliparous women at term in their first pregnancy (who had at least one subsequent pregnancy), and also identified perinatal outcomes in subsequent deliveries according to the type of labour in the first pregnancy. RESULTS: A total of 37 756 pregnancies satisfied inclusion and exclusion criteria; of these, 1382 (3.7%) had a Caesarean section without labour in the first pregnancy. Rates of most adverse perinatal outcomes were low (≤ 1%). The risks for stillbirth were low in subsequent deliveries, including those that followed CS without labour in the first pregnancy, and the risks for the overall severe perinatal morbidity outcome were less than 10% for all subsequent deliveries. CONCLUSION: The absolute risks for severe perinatal morbidity outcomes in a population of low-risk women (with up to four additional pregnancies) were small, regardless of type of labour in the first pregnancy. This finding provides important information on perinatal outcomes in subsequent pregnancies when considering type of labour in the first pregnancy.

Type of Labour in the First Pregnancy and Cumulative Maternal Morbidity.

OBJECTIVE: To estimate cumulative maternal morbidity among women who delivered at term in their first pregnancy on the basis of type of labour in the first pregnancy. METHODS: Using a 25-year population-based cohort (1988 to 2012) derived from the Nova Scotia Atlee Perinatal Database, we determined the type of labour in successive pregnancies in low-risk, nulliparous women at term in their first pregnancy (who had at least one subsequent pregnancy), and the maternal outcomes in subsequent deliveries based on the type of labour in the first pregnancy. RESULTS: A total of 36 871 pregnancies satisfied inclusion and exclusion criteria, 1346 of which were delivered by Caesarean section without labour in the first pregnancy. Rates of most adverse maternal outcomes were low (≤1%). The type of labour in the first pregnancy influenced the subsequent risk of postpartum hemorrhage and blood transfusion, and the risks increased with successive deliveries when labours were spontaneous in onset or were induced. The risks for abnormal placentation were low with subsequent deliveries, including following CS without labour in the first pregnancy, and risks for overall severe maternal morbidity were less than 10% for all subsequent deliveries. CONCLUSION: The absolute risks for severe maternal morbidity outcomes in a population of women without a high number of subsequent pregnancies were small (regardless of type of labour in the first pregnancy); this provides important information for women, families, and caregivers when considering pregnancy outcomes related to type of labour.

Objectif : Estimer la morbidité maternelle cumulative chez les femmes qui ont accouché à terme dans le cadre de leur première grossesse, en fonction du type de travail au cours de celle-ci. Méthodes : En utilisant une étude de cohorte de 25 ans en population générale (de 1988 à 2012) issue de la Nova Scotia Atlee Perinatal Database, nous avons déterminé le type de travail dans le cadre des grossesses successives chez des femmes exposées à de faibles risques qui ont accouché à terme dans le cadre de leur première grossesse (et qui ont connu au moins une autre grossesse), ainsi que les issues maternelles dans le cadre des accouchements subséquents, en fonction du type de travail dans le cadre de la première grossesse. Résultats : Au total, 36 871 grossesses ont satisfait aux critères d'inclusion et d'exclusion (dont 1 346 qui se sont soldées en une césarienne sans travail dans le cadre de la première grossesse). Les taux de la plupart des issues indésirables maternelles étaient faibles (≤ 1 %). Le type de travail dans le cadre de la première grossesse a exercé une influence sur le risque subséquent d'hémorragie postpartum et de transfusion sanguine; de plus, les risques ont connu une hausse dans le cadre des accouchements successifs lorsque le travail était spontané ou qu'il était déclenché. Les risques de placentation anormale étaient faibles dans le cadre des accouchements subséquents, y compris à la suite d'une césarienne sans travail dans le cadre de la première grossesse; les risques de morbidité globale grave chez la mère étaient inférieurs à 10 % pour tous les accouchements subséquents. Conclusion : Au sein d'une population de femmes n'ayant pas connu un nombre élevé de grossesses subséquentes, les risques absolus de morbidité maternelle grave étaient faibles (peu importe le type de travail dans le cadre de la première grossesse); cela offre d'importants renseignements aux femmes, aux familles et aux soignants lorsque les issues de grossesse sont envisagées en fonction du type de travail.

Trends in the prevalence of cerebral palsy among very preterm infants (<31 weeks' gestational age).

BACKGROUND: The birth prevalence of cerebral palsy varies over time among very preterm infants, and the reasons are poorly understood. OBJECTIVE: To describe the variation in the prevalence of cerebral palsy among very preterm infants over time, and to relate these differences to other maternal or neonatal factors. METHODS: A population-based cohort of very preterm infants was evaluated over a 20-year period (1988 to 2007) divided into four equal epochs. RESULTS: The prevalence of cerebral palsy peaked in the third epoch (1998 to 2002) while mortality rate peaked in the second epoch (1993 to 1997). Maternal anemia, tocolytic use and neonatal need for home oxygen were highest in the third epoch. CONCLUSIONS: Lower mortality rates did not correlate well with the prevalence of cerebral palsy. Maternal risk factors, anemia and tocolytic use, and the newborn need for home oxygen were highest during the same epoch as the peak prevalence of cerebral palsy.

HISTORIQUE: La prévalence de paralysie cérébrale à la naissance varie au fil du temps chez les nourrissons très prématurés, et on en comprend mal les raisons. OBJECTIF: Décrire la variation de la prévalence de paralysie cérébrale chez les nourrissons très prématurés au fil du temps et les relier à d'autres facteurs relatifs à la mère ou à la période néonatale. MÉTHODOLOGIE: Les chercheurs ont évalué une cohorte de nourrissons très prématurés sur 20 ans (1988 à 2007), divisée en quatre périodes d'égale longueur. RÉSULTATS: La prévalence de paralysie cérébrale a atteint un pic pendant la troisième période (1998 à 2002), tandis que le pic du taux de mortalité est survenu pendant la deuxième période (1993 à 1997). L'anémie et l'utilisation de tocolytiques chez la mère, ainsi que l'assistance ventilatoire néonatale à domicile, étaient plus élevées pendant la troisième période. CONCLUSIONS: Les taux de mortalité plus faibles n'étaient pas bien corrélés avec la prévalence de paralysie cérébrale. Les facteurs de risque de la mère, c'est-à-dire l'anémie et l' utilisation de tocolytiques, de même que l'assistance ventilatoire du nouveau-né à domicile, étaient tous plus élevés pendant la période qui s'associait à la plus forte prévalence de paralysie cérébrale.

Overlapping compared with end-to-end repair of complete third-degree or fourth-degree obstetric tears: three-year follow-up of a randomized controlled trial.

OBJECTIVE: To report on a 3-year follow-up of women who underwent overlapping repair of a complete third-degree or fourth-degree obstetric tear. METHODS: Primiparous women sustaining a complete third-degree or a fourth-degree tear of the perineum were randomized to a primary sphincter repair using either an end-to-end or an overlapping surgical technique. At 1, 2, and 3 years, questionnaires on rates of flatal and fecal incontinence were mailed to participants. RESULTS: At 1 year, women who underwent an end-to-end repair reported lower rates of flatal and fecal incontinence than women who had an overlapping repair. For flatal incontinence the rates were 31% compared with 56% (95% confidence interval for the rate difference 6-43%, P=.012). For fecal incontinence, the rates were 7% compared with 16% (95% confidence interval for the rate difference -4% to 21%, P=.17). The difference between the two methods of surgical repair had largely disappeared by the end of year 2. CONCLUSION: At 1-year follow-up, end-to-end repair of complete third-degree or fourth-degree obstetric anal sphincter tears is associated with significantly lower rates of anal incontinence when compared with overlapping repair. There is no long-term benefit associated with either technique over the other. CLINICAL TRIAL REGISTRATION: ISRCTN Register, http://isrctn.org, ISRCTNO 4149919. LEVEL OF EVIDENCE: I.

Neonatal outcome following failed Kiwi OmniCup vacuum extraction.

OBJECTIVE: To evaluate neonatal outcomes following failed vacuum extraction using the Kiwi OmniCup vacuum device. METHODS: We conducted a retrospective study of 288 failed vacuum deliveries using the OmniCup device. The neonatal morbidity was recorded for each delivery. RESULTS: Of the 288 women involved, 82.3% were nulliparous. In 245 cases (85.1%), failed vacuum was followed by successful forceps delivery; failed vacuum and failed forceps was followed by Caesarean section in 5.9%; failed vacuum was followed by spontaneous vaginal delivery in 3.8%; and failed vacuum was followed by Caesarean section in 5.2%. Cephalhematoma was diagnosed in 19.8% of the 288 infants delivered. There were no cases of neonatal intracranial or subgaleal hemorrhage. CONCLUSION: Although the method of delivery following failed vacuum extraction is controversial, and most national guidelines warn of increased neonatal morbidity with subsequent use of forceps, the low morbidity in this study is reassuring. In our cohort, low forceps delivery (station > 2 cm) following failed vacuum extraction was not associated with serious neonatal morbidity.

The influence of changing post-term induction of labour patterns on severe neonatal morbidity.

OBJECTIVE: To estimate the influence of changing practice patterns of post-term induction of labour on severe neonatal morbidity. METHODS: This population-based cohort study used data from the Nova Scotia Atlee Perinatal Database to evaluate the effect of post-term induction of labour on stillbirth and neonatal mortality and severe neonatal morbidity in low-risk pregnancies. The study population included all pregnant women ≥ 40 weeks' gestation delivering in Nova Scotia from 1988 to 2008 who underwent induction of labour with a single fetus in cephalic presentation. Major congenital anomalies and pre-existing or severe gestational hypertension and diabetes were excluded. Women delivering post-term from 1994 to 2008 (after the Post-term Pregnancy Trial) were compared with women delivering from 1988 to 1992 to evaluate outcomes with changing maternal characteristics and obstetric practice patterns. RESULTS: Evaluation and comparison of time epochs (1988 to 1992, 1994 to 1998, 1999 to 2003, and 2004 to 2008) demonstrated an increased risk for perinatal mortality or severe neonatal morbidity, especially low five-minute Apgar score, among both nulliparous and multiparous women. There were no significant differences in the risks for stillbirth or perinatal mortality over time. Comparable relationships were demonstrated in a subgroup of lower risk women. CONCLUSION: The increase in post-term induction of labour with time is associated with a significant increase in severe neonatal morbidity, especially among infants born to multiparous women. Evaluation of the antepartum and intrapartum management of these low-risk pregnancies may provide additional information to reduce morbidity.

Acute disseminated intravascular coagulation in obstetrics: a tertiary centre population review (1980 to 2009).

OBJECTIVE: To determine the antecedent factors, morbidity, and mortality associated with disseminated intravascular coagulation (DIC) in a Nova Scotia tertiary maternity hospital over a 30-year period. METHODS: Cases of DIC were identified from the Nova Scotia Atlee Perinatal Database for the years 1980 to 2009 and the hospital charts reviewed. The clinical diagnosis of DIC was confirmed or refuted using a combination of the International Society of Thrombosis and Haemostasis scoring system and an obstetrical DIC-severity staging system. The cause of DIC was determined from chart review. Maternal outcomes included massive transfusion (≥ 5 units), hysterectomy, admission to ICU, acute tubular necrosis (ATN) requiring dialysis, and death. Neonatal outcomes included Apgar scores, birth weight, NICU admission, and death. Treatment of DIC was assessed by blood products administered, postpartum hemorrhage management, and laboratory measurements. RESULTS: There were 49 cases of DIC in 151 678 deliveries (3 per 10,000) over the 30 years. Antecedent causes included placental abruption (37%), postpartum hemorrhage or hypovolemia (29%), preeclampsia/HELLP (14%), acute fatty liver (8%), sepsis (6%), and amniotic fluid embolism (6%). The associated maternal morbidity included transfusion ≥ 5 units (59%), hysterectomy (18%), ICU admission (41%), and ATN requiring dialysis (6%). There were three maternal deaths, giving a case fatality rate of 1 in 16. The perinatal outcomes included stillbirth (25%), neonatal death (5%), and NICU admission (72.5%). CONCLUSION: Obstetrical DIC is an uncommon condition associated with high maternal and perinatal morbidity and mortality. Prompt recognition and treatment with timely administration of blood products is crucial in the management of this life-threatening disorder.

Contribution of select maternal groups to temporal trends in rates of caesarean section.

OBJECTIVE: To estimate the contribution of select maternal groups to temporal trends in Caesarean section (CS) rates. METHODS: Using the Nova Scotia Atlee Perinatal Database, all deliveries by CS during the 24-year period from 1984 to 2007, at the Women's Hospital, IWK Health Centre were identified. Deliveries by CS were classified into groups using parity (nullipara/multipara), plurality (singleton/multiple), presentation (cephalic/breech/transverse), gestational age (term/preterm), history of previous CS (previous CS/no previous CS), and labour (spontaneous/induced/no labour). CS rates in each group and the contribution of each group to the overall CS rate was determined for three eight-year epochs. The risk of CS in each group over time, accounting for identified maternal, fetal, and obstetric practice factors, was evaluated using logistic regression. RESULTS: Of 113,016 deliveries, 23,232 (20.6%) were identified as deliveries by CS meeting the inclusion and exclusion criteria. The CS rate rose from 16.8% in 1984 to 1991 to 26.8% in 2000 to 2007 (P < 0.001). The biggest contributors to the overall CS rate in the last study epoch (2000-2007) were nulliparous women with singleton, cephalic, term pregnancies with spontaneous or induced labour; women with singleton, cephalic, term pregnancies with previous CS; and women with breech presentation. Adjusted analyses explained some increases in the rate of CS and demonstrated reduced risks in others. CONCLUSION: Only some temporally increased CS rates in select maternal groups remain increased after adjusting for confounding variables. The identification of potentially modifiable maternal risk factors, re-evaluation of the indications and techniques for induction of labour in nulliparous women, provision of clinical services for vaginal birth after Caesarean section, and external cephalic version for selected breech presentation are important clinical management areas to consider for safely lowering the Caesarean section rate.

Overlapping compared with end-to-end repair of third- and fourth-degree obstetric anal sphincter tears: a randomized controlled trial.

OBJECTIVE: To compare overlapping repair with end-to-end repair of obstetric tears and to investigate which procedure results in a higher rate of flatal incontinence. METHODS: One-hundred forty-nine primiparous women sustaining a complete third- or a fourth-degree tear of the perineum were assigned randomly to a primary sphincter repair using either an end-to-end (n=75) or an overlapping surgical technique (n=74) using 3-0 polyglyconate. Outcome measures at 6 months included rates of flatal and fecal incontinence, quality-of-life scores, integrity of the internal and external anal sphincters by anal ultrasonography, and anal sphincter function as reflected by anal manometry. RESULTS: Women who underwent overlapping repair compared with end-to-end repair had higher rates of flatal incontinence, 61% compared with 39% (odds ratio [OR] 2.44, confidence interval [CI] 1.2-5.0). The rate of fecal incontinence was also higher, 15% compared with 8% (OR 1.97, CI 0.62-6.3) but did not attain statistical significance. Rates of internal and external anal sphincter defects did not differ significantly between groups and did not correlate with anal incontinence symptoms. Fecal incontinence was higher when there was a defect in both sphincter muscles. Anal sphincter function as assessed by manometry did not differ significantly between groups. CONCLUSION: End-to-end repair of third- or fourth-degree obstetric anal sphincter tears is associated with lower rates of anal incontinence when compared with overlapping repair. CLINICAL TRIAL REGISTRATION: ISRCTN Register, isrctn.org, ISRCTN04149919. LEVEL OF EVIDENCE: I.

Maternal critical care in obstetrics.

OBJECTIVE: To determine the factors leading to maternal critical care in a tertiary obstetric hospital and the associated trends. METHODS: We conducted a review of the medical records of all women who required transfer for critical care from a free-standing obstetric unit to a general hospital over a 24-year period (1982-2005). RESULTS: During the 24-year period there were five maternal deaths directly associated with 122,001 deliveries (4.1/100,000) and, in addition, 117 women were transferred to the general hospital for critical care (1.0/1000). The death-to-transfer ratio was 1 in 23. Of the women transferred, 93/117 (79.5%) required intensive care and 24/117 (20.5%) needed specialized medical or surgical services not available in the obstetric unit. Of the women transferred, 16/117 (13.7%) were antepartum, and 101/117 (86.3%) were postpartum. Hemorrhage and hypertensive disorders combined to make up 56.4% of all maternal transfers. Women with a multiple pregnancy were more likely to require transfer than those with a singleton pregnancy (RR 3.34; 95% CI 1.4-7.59, P=0.01). CONCLUSION: The majority of maternal transfers for critical care occur postpartum, and in more than half of the cases the reason for transfer is hemorrhage or hypertensive disease. Women with a multiple pregnancy had a significantly greater rate of transfer than those with a singleton, and women with a triplet pregnancy had a greater rate than those with twins. There was a non-significant increase in the number of maternal transfers over the study period.