Perinatal morbidity associated with late preterm deliveries compared with deliveries between 37 and 40 weeks of gestation

European guidelines on perinatal care: corticosteroids for women at risk of preterm birth

of recommendationsCorticosteroids should be administered to women at a gestational age between 24⁺⁰ and 33⁺⁶weeks, when preterm birth is anticipated in the next seven days, as these have been consistently shown to reduce neonatal mortality and morbidity. (Strong-quality evidence; strong recommendation). In selected cases, extension of this period up to 34⁺⁶weeks may be considered (Expert opinion). Optimal benefits are found in infants delivered within 7 days of corticosteroid administration. Even a single-dose administration should be given to women with imminent preterm birth, as this is likely to improve neurodevelopmental outcome (Moderate-quality evidence; conditional recommendation).Either betamethasone (12 mg administered intramuscularly twice, 24-hours apart) or dexamethasone (6 mg administered intramuscularly in four doses, 12-hours apart, or 12 mg administered intramuscularly twice, 24-hours apart), may be used (Moderate-quality evidence; Strong recommendation). Administration of two "all" doses is named a "course of corticosteroids".Administration between 22⁺⁰ and 23⁺⁶weeks should be considered when preterm birth is anticipated in the next seven days and active newborn life-support is indicated, taking into account parental wishes. Clear survival benefit has been observed in these cases, but the impact on short-term neurological and respiratory function, as well as long-term neurodevelopmental outcome is still unclear (Low/moderate-quality evidence; Weak recommendation).Administration between 34 + 0 and 34 + 6 weeks should only be offered to a few selected cases (Expert opinion). Administration between 35⁺⁰ and 36⁺⁶weeks should be restricted to prospective randomized trials. Current evidence suggests that although corticosteroids reduce the incidence of transient tachypnea of the newborn, they do not affect the incidence of respiratory distress syndrome, and they increase neonatal hypoglycemia. Long-term safety data are lacking (Moderate quality evidence; Conditional recommendation).Administration in pregnancies beyond 37⁺⁰weeks is not indicated, even for scheduled cesarean delivery, as current evidence does not suggest benefit and the long-term effects remain unknown (Low-quality evidence; Conditional recommendation).Administration should be given in twin pregnancies, with the same indication and doses as for singletons. However, existing evidence suggests that it should be reserved for pregnancies at high-risk of delivering within a 7-day interval (Low-quality evidence; Conditional recommendation). Maternal diabetes mellitus is not a contraindication to the use of antenatal corticosteroids (Moderate quality evidence; Strong recommendation).A single repeat course of corticosteroids can be considered in pregnancies at less than 34⁺⁰weeks gestation, if the previous course was completed more than seven days earlier, and there is a renewed risk of imminent delivery (Low-quality evidence; Conditional recommendation).

Management of Intrahepatic Cholestasis of Pregnancy: Recommendations of the Working Group on Obstetrics and Prenatal Medicine - Section on Maternal Disorders

Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disease specific to pregnancy. The cardinal symptom of pruritus and a concomitant elevated level of bile acids in the serum and/or alanine aminotransferase (ALT) are suggestive for the diagnosis. Overall, the maternal prognosis is good. The fetal outcome depends on the bile acid level. ICP is associated with increased risks for adverse perinatal outcomes, including preterm delivery, meconium-stained amniotic fluid, and stillbirth. Acute fetal asphyxia and not chronic uteroplacental dysfunction leads to stillbirth. Therefore, predictive fetal monitoring is not possible. While medication with ursodeoxycholic acid (UDCA) improves pruritus, it has not been shown to affect fetal outcome. The indication for induction of labour depends on bile acid levels and gestational age. There is a high risk of recurrence in subsequent pregnancies.

Late preterm births: neonatal mortality and morbidity in twins vs. singletons

OBJECTIVE

To examine the outcomes of twins and singletons in the late preterm period.

MATERIALS AND METHODS

This is a retrospective cohort study of data obtained for 165,894 births in California who delivered between 34 + 0 and 36 + 6 weeks. The primary outcome was neonatal and infant mortality. The secondary outcomes included the following neonatal morbidities: respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), seizure, and sepsis. Univariate analysis was performed using chi-square test and multivariable logistic regression was used to adjust for potential confounders.

RESULTS

There were 143,891 singleton and 22,003 twin gestations included in the study. There was no difference in the primary outcome, neonatal and infant mortality between twins and singletons delivered at 34 and 36 weeks. After controlling for multiple potential confounders, significant differences in secondary outcomes of neonatal morbidity were identified. At 34 weeks, twins had significantly higher rates of IVH (aOR 2.47 (95%CI 1.08-5.64)), NEC (aOR 2.46 (95%CI 1.42-4.29)), RDS (aOR 1.60 (95%CI 1.45-1.77)), and sepsis (aOR 1.19 (95%CI 1.05-1.34)) compared to singletons. By 36 weeks, only an increased risk of RDS persisted among twins.

CONCLUSIONS

While there was no difference in mortality among twins and singletons in the late preterm period, twins may have significantly increased neonatal morbidity compared to singletons delivered between 34 + 0 and 36 + 6 weeks.

Neonatal Morbidities in Infants Born Late Preterm at 35-36 Weeks of Gestation: A Swedish Nationwide Population-based Study

OBJECTIVE

To assess risk for neonatal morbidities among infants born late preterm at 35-36 gestational weeks, early term (37-38 weeks), and late-term (41 weeks) infants, compared with full-term (39-40 weeks) infants.

STUDY DESIGN

This nationwide population-based cohort study included 1 650 450 non-malformed liveborn singleton infants born at 35-41 weeks between 1998 and 2016 in Sweden. The relative risks for low Apgar score (0-3) at 5 minutes; respiratory, metabolic, infectious, and neurologic morbidities; and severe neonatal morbidity (composite outcome) were adjusted for maternal, pregnancy, delivery, and infant characteristics.

RESULTS

Compared with infants born at 39-40 weeks, the adjusted relative risks and proportions of infants born at 35-36 weeks were higher for metabolic morbidity 7.79 (95%, 7.61 to 7.97; 33.75% vs 3.11%), respiratory morbidity 5.54 (95% CI, 5.24 to 5.85; 5.49% vs 0.75%), severe neonatal morbidity 2.42 (95% CI, 2.27 to 2.59; 3.40% versus 1.03%), infectious morbidity 1.98 (95% CI, 1.83 to 2.14; 2.53% vs 0.95%), neurologic morbidity 1.74 (95% CI, 1.48 to 2.03; 0.54% vs 0.23%), and low Apgar score 2.07 (95% CI, 1.72 to 2.51; 0.42% vs 0.12%). The risks for respiratory, severe neonatal morbidity, infectious, neurologic morbidities, and low Apgar score were highest at 35 weeks, gradually decreased until 39 weeks, and increased during 39-41 weeks.

CONCLUSIONS

Infants born late preterm at 35-36 weeks of gestation are at increased risk of neonatal morbidities, although the absolute risks for severe neonatal morbidities are low. Our findings reinforce the need of preventing late preterm delivery to decrease the burden of neonatal morbidity and help professionals and families with a better risk assessment.

Timing of Repeat Cesarean Delivery for Women with a Prior Classical Incision

OBJECTIVE

This study aimed to compare neonatal outcomes for delivery at 36 weeks compared with 37 weeks in women with prior classical cesarean delivery (CCD).

STUDY DESIGN

This was a secondary analysis of the prospective observational cohort of the Eunice Kennedy National Institute for Child and Human Development's Maternal-Fetal Medicine Unit Network Cesarean Registry. Data on cases of repeat cesarean delivery (RCD) in the setting of a prior CCD were abstracted and used for analysis. This study compared outcomes of women who delivered at 36^0/7 to 36^6/7 versus 37^0/7 to 37^6/7 weeks. The primary outcome was a composite of adverse neonatal outcomes that included neonatal intensive care unit (NICU) admission, respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), hypoglycemia, mechanical ventilation, sepsis, length of stay ≥5 days, and neonatal death. A composite of maternal outcomes that included uterine rupture, blood transfusion, general anesthesia, cesarean hysterectomy, venous thromboembolism, maternal sepsis, intensive care unit admission, and surgical complications was also evaluated.

RESULTS

There were 436 patients included in the analysis. Women who delivered at 36 weeks (n = 176) were compared those who delivered at 37 weeks (n = 260). There were no differences in baseline characteristics. Delivery at 37 weeks was associated with a reduction in composite neonatal morbidity (24 vs. 34%, adjusted odds ratio [aOR] = 0.61 [0.31-0.94]), including a decrease in NICU admission rates (20 vs. 29%, aOR = 0.63 [0.40-0.99]), hospitalization ≥5 days (13 vs. 24%, aOR = 0.48 [0.29-0.8]), and RDS or TTN (9 vs. 19%, aOR = 0.43 [0.24-0.77]). There was no difference in adverse maternal outcomes (7 vs. 7%, aOR = 0.98 [0.46-2.09]).

CONCLUSION

Delivery at 37 weeks for women with a history of prior CCD is associated with a decrease in adverse neonatal outcomes, compared with delivery at 36 weeks.

KEY POINTS

· Classical cesarean section may have increased risk of uterine rupture in future pregnancies.. · This study compares outcomes of delivery at 370/7 to 376/7 versus 360/7 to 366/7 weeks.. · Delivery at 370/7 to 376/7 weeks was associated with decreased neonatal morbidity..

[Intrahepatic cholestasis of pregnancy]

Die Schwangerschaftscholestase („intrahepatic cholestasis of pregnancy“, ICP) ist die häufigste schwangerschaftsspezifische Lebererkrankung. Das Leitsymptom Juckreiz sowie eine begleitende Serumkonzentrationserhöhung von Gallensäuren und/oder der Alaninaminotransferase (ALT) sind wegweisend in der Diagnosestellung. Die mütterliche Prognose ist gut. Das fetale Outcome ist abhängig von der Gallensäurenkonzentration. Die ICP ist dabei sowohl mit Frühgeburt als auch mit intrauterinem Fruchttod (IUFT) assoziiert. Dieser ist Folge einer akuten fetalen Asphyxie, nicht einer chronischen uteroplazentaren Dysfunktion. Ein prädiktives Monitoring, z. B. durch Kardiotokographie (CTG) oder Ultraschall gibt es nicht. Eine medikamentöse Therapie mit Ursodeoxycholsäure (UDCA) bessert den Juckreiz, aber beeinflusst das fetale Outcome nicht nachweislich. Eine Entbindungsindikation ist in Abhängigkeit von Gallensäurenkonzentration und Gestationsalter gegeben. In Folgeschwangerschaften besteht ein hohes Wiederholungsrisiko.

Reference intervals for 26 common biochemical analytes in term neonates in Jilin Province, China

Background

Biochemical analytes provide information for neonatal disease management and therapy, and population-based reference intervals (RIs) are essential to accurately interpret laboratory test results. This study aimed to establish local RIs for biochemical assays in term neonates.

Methods

A total of 195 healthy term neonates from birth to 3rd day were recruited as reference individuals prospectively. Analytes of 26 common biochemistries were measured using the VITROS 5600 Integrated System. The 3-level nested ANOVA was performed to assess the need for partitioning RIs of each analyte, and RIs were derived by a nonparametric method or robust method. Multiple regression analysis was used to evaluate specific correlations between the analytes and individual characteristics including age, gender, gestational age, birthweight and delivery mode.

Results

There were no between-sex differences in all analytes, whereas there were significant between-day-age differences in 6 analytes. Small between-delivery-mode differences were observed in the results for potassium, phosphorus, and urea. The major related factor of most analytes was postnatal age. During the first 3 days, values of iron, lipids and lipoproteins increased; creatinine, urea, uric acid, creatine kinase and lactate dehydrogenase decreased; other analytes showed slight changes or relatively stable trends. Reference limits of some analytes, particularly lactate dehydrogenase and alkaline phosphatase, were significantly different from adult and pediatric groups.

Conclusions

RIs of 26 common biochemical analytes are established for term neonates aged 0 to 3 days in northeast China. Additionally, it is suggested that age-related changes should be valued in the clinical decision-making process for newborns.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02565-8.

Pregnancy duration with use of 17-α-hydroxyprogesterone caproate in a retrospective cohort at high risk of recurrent preterm birth

BACKGROUND

The use of 17-α-hydroxyprogesterone caproate for the prevention of recurrent spontaneous preterm birth has become widespread, yet there are conflicting data regarding its efficacy.

OBJECTIVE

We sought to determine whether administration of 17-α-hydroxyprogesterone caproate was associated with pregnancy prolongation in women at a high risk of recurrent spontaneous preterm birth.

STUDY DESIGN

This is a retrospective cohort study of women with singleton pregnancies and a history of spontaneous preterm birth at <37 weeks' gestation who received care at our academic tertiary care center between 2009 and 2019. We included women with gestations that progressed beyond 16 weeks. We excluded those who underwent history-indicated cerclage placement. We first examined the characteristics of women who received 17-α-hydroxyprogesterone caproate and those who did not. Covariates with a P value of ≤.2 on this univariate analysis were considered for incorporation into a Cox proportional hazards model to assess the association between 17-α-hydroxyprogesterone caproate use and pregnancy prolongation up to 35 weeks.

RESULTS

Of 861 women included in the study, 570 (66.2%) reported non-Hispanic black racial identity, 237 (27.5%) lived in zip codes with a high infant mortality rate (≥12.1/1000 infants), 287 (33.3%) had more than 1 previous spontaneous preterm birth, 372 (43.2%) had previous spontaneous preterm birth at ≤32 weeks' gestation, and 242 (28.1%) were smokers. Here, 152 pregnancies (17.6%) were complicated by spontaneous preterm birth at <35 weeks' gestation. Factors independently associated with pregnancy duration up to 35 weeks included weight gain of <0.2 kg (0.5 lb) per week, first recorded weight of <98 kg (215 lb), obstetrical history, non-Hispanic white racial identity, lack of prenatal care, and vaginal bleeding. Gestational age at delivery was also independently associated with interventions typically employed for midtrimester cervical shortening and/or dilation, including ultrasound- and examination-indicated cerclage, pessary placement, and vaginal progesterone administration. The use of 17-α-hydroxyprogesterone caproate was not associated with pregnancy prolongation (adjusted hazard ratio, 0.83; 95% confidence interval, 0.60-1.15).

CONCLUSION

The risk profile of our cohort is similar to that of women enrolled in the landmark trial that led to the Food and Drug Administration's approval of 17-α-hydroxyprogesterone caproate. Despite the high-risk nature of the pregnancies examined, we found no association between use of the medication in daily clinical practice and pregnancy prolongation up to 35 weeks. This finding adds to the mounting evidence that calls into question the drug's efficacy in reducing the risk of recurrent spontaneous preterm birth.

The effect of antenatal corticosteroids on small-for-gestational age preterm neonates

Objective: Treatment of preterm small-for-gestational age (SGA) neonates with antenatal corticosteroids (ACS) is not entirely straightforward. We sought to examine the effect of a full course of ACS on outcomes of SGA and non-SGA preterm singletons.Patients and methods: We compared maternal characteristics and outcomes of preterm births at <28 and 28 + 0-33 + 0 weeks' gestation that received a complete course of ACS within a week before birth. We further divided our cohort into those with or without a SGA neonate.Results: We included 290 infants: 73 (25.2%) and 217 (74.8%) born at <28 and 28 + 0-33 + 0 weeks' gestation, respectively. Analysis of maternal characteristics showed a strong association of maternal body mass index (p = .01), along with smoking during pregnancy (OR 0.4, 95% CI 0.2, 0.9), with being SGA. Spontaneous onset of delivery more commonly occurred in non-SGA preterm neonates, whereas iatrogenic induction of labor prevailed with SGA neonates (p < .01). There was no significant difference between SGA and non-SGA infants in all the tested neonatal variables except for necrotizing enterocolitis, which prevailed in the SGA group.Conclusion: A full course of ACS appears to have the same effect in SGA and non-SGA preterm singletons in our studied cohort on all neonatal outcomes but for necrotizing enterocolitis, where its role in SGA preterm neonates seems to be detrimental rather than beneficial to the fetus.

Meconium aspiration syndrome: Incidence and outcomes using discharge data

BACKGROUND

Meconium aspiration syndrome (MAS) is a leading cause of morbidity and mortality among term, otherwise healthy newborns, yet population studies are rare. Definitions, outcomes and International Classification of Diseases (ICD) codes are heterogenous, complicating estimates of incidence, outcomes and risks.

AIMS

To measure population incidence, risks and outcomes of MAS by ICD codes.

STUDY DESIGN

Retrospective population study.

SUBJECTS

Kids Inpatient Database (KID) 2012, a nationally representative weighted sample of newborn discharges in the United States.

OUTCOME MEASURES

Incidence, demographic distribution, and comorbidity associated with MAS.

RESULTS

In 2012 there were 9295 weighted discharges diagnosed MAS with symptoms (2.49/1000) and 4304 cases without symptoms (1.15/1000). Newborns with symptoms had nearly twice the length of stay (LOS) (6.68 vs 3.65 days, p 0.001) and nearly 3 times the total charges ($44,473 versus $15,461, p < 0.001) as those without symptoms. Incidence of death was over four times higher (7.7/1000 vs 1.7/1000, p < 0.001), persistent pulmonary hypertension 3 times higher (57.6/1000 vs 15.8/1000, p < 0.001), and hypoxic ischemic encephalopathy 5 times higher (6.2/1000 vs 1.2/1000, p < 0.001) among MAS cases with respiratory symptoms than MAS cases without respiratory symptoms. Odds ratio of MAS with symptoms was 1.54 (95% CI 1.39-1.73) for black newborns compared to whites.

CONCLUSIONS

Discharge data are useful for providing population estimates of MAS incidence. Prior studies have used consolidated ICD codes for MAS (with and without respiratory symptoms), yet these represent very different disease severities. Combining MAS diagnoses with and without respiratory symptoms misrepresents incidence and disease severity, complicating comparisons of outcomes and prevention strategies.

Short term outcomes in term and late preterm neonates admitted to the well-baby nursery after resuscitation in the delivery room

OBJECTIVE

To determine the risk for deterioration in well-baby nursery (WBN) admissions after resuscitation.

STUDY DESIGN

A single center retrospective study (2015-2016) of 370 resuscitated WBN admissions.

RESULTS

Of the 11,307 admissions, 3.27% received resuscitation with 183 receiving continuous positive airway pressure (CPAP) alone and 187 receiving positive pressure ventilation (PPV) ± CPAP. Resuscitated neonates were more frequently transferred to the NICU (11.6 versus 3.9%, p < 0.001) compared to those without resuscitation. More neonates requiring CPAP alone were transferred to the NICU compared to those requiring PPV ± CPAP (15.85 versus 7.49%, p = 0.01). Univariate risk ratios for transfer were elevated for CPAP alone and lower gestational age categories. Multivariate regression analyses demonstrated increased transfer risk across gestational age categories only.

CONCLUSIONS

Neonates admitted to the WBN after delivery room resuscitation are at increased risk for NICU transfer compared to those without resuscitation. This study supports the recommendation for post-resuscitation care.

Antenatal corticosteroids after 34 weeks' gestation: Do we have the evidence?

There is evidence to support the use of antenatal corticosteroids prior to late preterm birth at 35⁺⁰ to 36⁺⁶ weeks' gestation and for specific 'at-risk' populations, such as planned cesarean section birth and infants of women with diabetes in pregnancy, to reduce short-term neonatal respiratory morbidity. However, the overall size of effect at late preterm and term gestational ages is less than for early and moderate preterm birth and should be countered against the potential harms. Evidence from randomized trials suggest an increase in the incidence of neonatal hypoglycemia after corticosteroid use prior to late preterm birth; any effect of antenatal corticosteroids on neonatal glycemic control after planned cesarean section birth or for infants born to mothers with diabetes in pregnancy is unknown. Accumulating evidence suggests neonatal hypoglycemia may adversely affect childhood development. To date, no trials of antenatal corticosteroids after 34 weeks' gestation have reliably assessed outcomes beyond the neonatal period.

Risk Factors for Preterm Birth following Open Fetal Myelomeningocele Repair: Results from a Prospective Cohort

BACKGROUND

Fetal myelomeningocele (fMMC) repair is a therapeutic option in selected cases. This study aimed to identify risk factors for preterm birth (PTB) following open fMMC repair.

METHODS

Sixty-seven women underwent fMMC repair and delivered a baby between 2010 and 2018 at our center. Demographic, surgical, and pregnancy complications, including potential risk factors for PTB such as preterm premature rupture of membranes (PPROM), chorioamniotic membrane separation (CMS), and placental abruption were evaluated.

RESULTS

Maternal body mass index, maternal age, parity, previous uterine surgery, gestational age at fetal surgery, total surgery duration, surgical subcutaneous hematoma, oligohydramnios, and amniotic fluid leakage were not identified as risk factors for PTB. CMS (p = 0.028, 92 vs. 52%) and PPROM (p = 0.001, 95 vs. 52%) were highly associated with PTB. Placental abruption was found more often in women after fMMC repair than in a general obstetrical population (12 vs. 1%) and ended in premature birth in all cases (p = 0.024, 100 vs. 60%). However, the majority of women delivered at a gestational age >35 weeks.

CONCLUSIONS

In our study cohort, risk factors for PTB were PPROM, CMS, and placental abruption, whereas surgery duration did not influence outcome. We conclude that the surgery technique should aim to minimize CMS and amniotic fluid leakage.

Association between maternal and umbilical cord serum cobalt concentration during pregnancy and the risk of preterm birth: The Ma'anshan birth cohort (MABC) study

Cobalt is an essential trace element and has been suggested to be involved in oxidative stress and inflammatory responses. However, researches have paid little attention to the association between serum cobalt levels during pregnancy and the risk of preterm birth (PTB, <37 week of gestation). The purpose of this study was to determine the association between maternal and umbilical cord serum cobalt concentrations and the risk of PTB. A total of 2951, 3080, and 2698 serum samples were obtained from pregnant women in the first, the second trimester, and the umbilical cord blood, respectively. The tertile levels of ln-transformed cobalt were defined as low, medium and high levels for cobalt respectively. In our study, the rate of PTB (<37 weeks of gestation) was elevated in subjects with low cobalt levels in the first trimester of pregnancy (adjusted OR 1.61, 95% CI: 1.01, 2.58) and the second trimester of pregnancy (adjusted OR 1.62, 95% CI: 1.03, 2.54). The adjusted OR for PTB was 2.46 (95% CI: 1.34, 4.53) among subjects with low cobalt levels and 2.22 (95% CI: 1.19, 4.15) among subjects with medium cobalt levels in the umbilical cord serum. Our findings demonstrated that the lower levels in maternal and umbilical cord serum cobalt were associated with the increased the risk of PTB.

Intellectual disability in children aged less than seven years born moderately and late preterm compared with very preterm and term-born children - a nationwide birth cohort study

BACKGROUND

Prematurity has been shown to be associated with an increased risk of intellectual disability (ID).

METHOD

The aim was to establish whether the prevalence of ID, defined as significant limitations in both intellectual (intelligence quotient below 70) and adaptive functioning among moderately preterm (MP; 32⁺⁰ -33⁺⁶  weeks) and late preterm (LP; 34⁺⁰ -36⁺⁶  weeks) infants, is increased compared with that in term infants (≥37⁺⁰  weeks). Antenatal and neonatal risk factors for ID among gestational age groups were sought. The national register study included all live-born infants in Finland in 1991-2008, excluding those who died before one year age, or had any major congenital anomaly or missing data. A total of 1 018 256 infants (98.0%) were analysed: very preterm (VP; <32⁺⁰  weeks, n = 6329), MP (n = 6796), LP (n = 39 928) and term (n = 965 203).

RESULTS

By the age of seven years, the prevalence of ID was 2.48% in the VP group, 0.81% in the MP group, 0.55% in the LP group and 0.35% in the term group. Intracranial haemorrhage increased the ID risk in all groups. Male sex and born small for gestational age predicted an increased risk in all but the MP group.

CONCLUSIONS

The prevalence of ID decreased with increasing gestational age. Prevention of intracranial haemorrhages may have a beneficial effect on the neurodevelopmental outcomes of neonates.

The prediction of late-onset preeclampsia: Results from a longitudinal proteomics study

BACKGROUND

Late-onset preeclampsia is the most prevalent phenotype of this syndrome; nevertheless, only a few biomarkers for its early diagnosis have been reported. We sought to correct this deficiency using a high through-put proteomic platform.

METHODS

A case-control longitudinal study was conducted, including 90 patients with normal pregnancies and 76 patients with late-onset preeclampsia (diagnosed at ≥34 weeks of gestation). Maternal plasma samples were collected throughout gestation (normal pregnancy: 2-6 samples per patient, median of 2; late-onset preeclampsia: 2-6, median of 5). The abundance of 1,125 proteins was measured using an aptamers-based proteomics technique. Protein abundance in normal pregnancies was modeled using linear mixed-effects models to estimate mean abundance as a function of gestational age. Data was then expressed as multiples of-the-mean (MoM) values in normal pregnancies. Multi-marker prediction models were built using data from one of five gestational age intervals (8-16, 16.1-22, 22.1-28, 28.1-32, 32.1-36 weeks of gestation). The predictive performance of the best combination of proteins was compared to placental growth factor (PIGF) using bootstrap.

RESULTS

1) At 8-16 weeks of gestation, the best prediction model included only one protein, matrix metalloproteinase 7 (MMP-7), that had a sensitivity of 69% at a false positive rate (FPR) of 20% (AUC = 0.76); 2) at 16.1-22 weeks of gestation, MMP-7 was the single best predictor of late-onset preeclampsia with a sensitivity of 70% at a FPR of 20% (AUC = 0.82); 3) after 22 weeks of gestation, PlGF was the best predictor of late-onset preeclampsia, identifying 1/3 to 1/2 of the patients destined to develop this syndrome (FPR = 20%); 4) 36 proteins were associated with late-onset preeclampsia in at least one interval of gestation (after adjustment for covariates); 5) several biological processes, such as positive regulation of vascular endothelial growth factor receptor signaling pathway, were perturbed; and 6) from 22.1 weeks of gestation onward, the set of proteins most predictive of severe preeclampsia was different from the set most predictive of the mild form of this syndrome.

CONCLUSIONS

Elevated MMP-7 early in gestation (8-22 weeks) and low PlGF later in gestation (after 22 weeks) are the strongest predictors for the subsequent development of late-onset preeclampsia, suggesting that the optimal identification of patients at risk may involve a two-step diagnostic process.

Delta-6 desaturase activity during the first year of life in preterm infants

Term neonates have high delta-6 desaturase (D6D) activity, which is important for regulating polyunsaturated fatty acid's (PUFA) nutritional status. The aim was to investigate D6D activity in preterm infants and its postnatal changes. Forty-three appropriate-for-gestational-age infants were included. PUFA in red blood cells was analyzed at birth and at one, six, and 12 months of age. D6D activity was estimated by 20:3n-6/18:2n-6 ratio. At birth, preterm infants had D6D activity as high as that of term infants; D6D activity declined to about one-third at one month, then further decreased to about one-sixth at six months and remained stable until 12 months. The postnatal change in arachidonic acid exhibited a similar pattern to that of D6D activity; however, docosahexaenoic acid showed a transient decrease at one month and recovered to the cord blood level at six months. D6D may regulate PUFA profile in preterm infants, especially during the early postnatal period.

The transition from intra to extra-uterine life in late preterm infant: a single-center study

BACKGROUND

Infants born at 34 to 36 weeks of gestation (late preterm) are at greater risk for adverse outcomes than those born at 37 weeks of gestation or later. Aim of this paper is to examine risk factors for late preterm births and to investigate the complications of the transition period in late preterm infants (LPIs).

METHODS

All consecutive late preterm deliveries, excluded stillbirths, were included. Maternal and neonatal data, need for delivery room resuscitative procedures, temperature at birth (T1) and two hours after the admission (T2) were analyzed in all LPIs stratified by Gestational Age (GA) and divided into three groups (34, 35 and 36 weeks).

RESULTS

Two hundred seventy-six LPIs were analyzed. Pregnancy complications were present in 72 mothers (26.1 %), more frequently at 34 weeks of gestation respect to 35 and 36 weeks (p = 0.008, p = 0.006 respectively). Forty seven LPIs (17.1 %) needed for any resuscitation and 37 (13.4 %) were ventilated at birth. LPIs at 34 weeks were significantly more likely to receive ventilation respect to those at 35 and 36. At T1 the mean temperature resulted lower at 34 weeks respect to 36 weeks (p = 0.03). At T2 respect to T1, the rate of normothermic neonates increased at 35 and 36 weeks (p = 0.003, p = 0.005, respectively). Hypoglicemia rate was similar among the groups; 66.7 % of hypoglicemic neonates were hypothermic at T1. The rate of respiratory diseases and NICU admission decreased with increasing GA. Higher number of neonates ventilated at birth developed respiratory disorders respect to those unventilated (40.5 % vs 8.4 %; p < 0.001).

CONCLUSIONS

Transition period in LPIs may become critical, as resuscitation strategies can be required and heat loss can occur. LPIs, especially at 34 gestational weeks, are higher-risk group needing adequate and targeted management at birth.

Neonatal respiratory morbidity in late-preterm births in pregnancies with and without gestational diabetes mellitus

OBJECTIVE

To evaluate neonatal respiratory morbidity in infants born late-preterm to mothers with or without gestational diabetes mellitus (GDM).

METHODS

Analysis of a population-based cohort of all live-born singletons, born at 34 0/7 to 36 6/7 weeks to mothers with and without GDM, focusing on transient tachypnea of the newborn (TTN) and respiratory distress syndrome (RDS).

RESULTS

The study group comprised 363 (4.7%) singletons born to mothers with GDM and the controls were 7400 born to mothers without GDM. Mothers with GDM were older (31.4 ± 5.1 versus 29.5 ± 5.1 years, p < 0.001) and were more likely to be hypertensive (OR 1.5, 95% CI 1.1-2.1). Neonates of GDM mothers were heavier at birth (2769 ± 539 versus 2636 ± 473 g, p < 0.001). We found a similar incidence of RDS and TTN in both groups. The multiple regression analysis showed cesarean delivery and lower gestational age were independently associated with RDS and TTN.

CONCLUSION

GDM, per se, is not a major contributor to RDS in late pre-term infants. Rather, the combination of prematurity and cesarean birth act independently to increase the risk of respiratory morbidity.

Towards reducing variations in infant mortality and morbidity: a population-based approach

Background

Our aims were (1) to improve understanding of regional variation in early-life mortality rates and the UK’s poor performance in international comparisons; and (2) to identify the extent to which late and moderately preterm (LMPT) birth contributes to early childhood mortality and morbidity.

Objective

To undertake a programme of linked population-based research studies to work towards reducing variations in infant mortality and morbidity rates.

Design

Two interlinked streams: (1) a detailed analysis of national and regional data sets and (2) establishment of cohorts of LMPT babies and term-born control babies.

Setting

Cohorts were drawn from the geographically defined areas of Leicestershire and Nottinghamshire, and analyses were carried out at the University of Leicester.

Data sources

For stream 1, national data were obtained from four sources: the Office for National Statistics, NHS Numbers for Babies, Centre for Maternal and Child Enquiries and East Midlands and South Yorkshire Congenital Anomalies Register. For stream 2, prospective data were collected for 1130 LMPT babies and 1255 term-born control babies.

Main outcome measures

Detailed analysis of stillbirth and early childhood mortality rates with a particular focus on factors leading to biased or unfair comparison; review of clinical, health economic and developmental outcomes over the first 2 years of life for LMPT and term-born babies.

Results

The deprivation gap in neonatal mortality has widened over time, despite government efforts to reduce it. Stillbirth rates are twice as high in the most deprived as in the least deprived decile. Approximately 70% of all infant deaths are the result of either preterm birth or a major congenital abnormality, and these are heavily influenced by mothers’ exposure to deprivation. Births at < 24 weeks’ gestation constitute only 1% of all births, but account for 20% of infant mortality. Classification of birth status for these babies varies widely across England. Risk of LMPT birth is greatest in the most deprived groups within society. Compared with term-born peers, LMPT babies are at an increased risk of neonatal morbidity, neonatal unit admission and poorer long-term health and developmental outcomes. Cognitive and socioemotional development problems confer the greatest long-term burden, with the risk being amplified by socioeconomic factors. During the first 24 months of life each child born LMPT generates approximately £3500 of additional health and societal costs.

Conclusions

Health professionals should be cautious in reviewing unadjusted early-life mortality rates, particularly when these relate to individual trusts. When more sophisticated analysis is not possible, babies of < 24 weeks’ gestation should be excluded. Neonatal services should review the care they offer to babies born LMPT to ensure that it is appropriate to their needs. The risk of adverse outcome is low in LMPT children. However, the risk appears higher for some types of antenatal problems and when the mother is from a deprived background.

Future work

Future work could include studies to improve our understanding of how deprivation increases the risk of mortality and morbidity in early life and investigation of longer-term outcomes and interventions in at-risk LMPT infants to improve future attainment.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Respiratory consequences of late preterm birth

In developed countries most preterm births occur between 34 and 37 weeks' gestation. Deliveries during this 'late preterm' period are increasing and, since even mild prematurity is now recognised to be associated with adverse health outcomes, this presents healthcare challenges. Respiratory problems associated with late preterm birth include neonatal respiratory distress, severe RSV infection and childhood wheezing. Late preterm birth prematurely interrupts in utero lung development and is associated with maternal and early life factors which adversely affect the developing respiratory system. This review considers 1) mechanisms underlying the association between late preterm birth and impaired respiratory development, 2) respiratory morbidity associated with late preterm birth, particularly long-term outcomes, and 3) interventions which might protect respiratory development by addressing risk factors affecting the late preterm population, including maternal smoking, early life growth restriction and vulnerability to viral infection.

The risk of stillbirth and infant death by each additional week of expectant management in twin pregnancies

OBJECTIVE

The objective of the study was to compare the fetal/infant mortality risk associated with each additional week of expectant management with the mortality risk of immediate delivery in women with twin gestations.

STUDY DESIGN

A retrospective cohort study was performed utilizing 2006-2008 National linked birth certificate and death certificate data. The incidence of stillbirth and infant death were determined for each week of pregnancy from 32 0/7 weeks' through 40 6/7 weeks' gestation. Pregnancies complicated by fetal anomalies were excluded. These measures were combined to estimate the theoretic risk of remaining pregnant an additional week by adding the risk of stillbirth during the extra week of pregnancy with the risk of infant death encountered with delivery during the following week. This composite fetal/infant mortality risk was compared with the risk of infant death associated with delivery at the corresponding gestational age.

RESULTS

The risk of stillbirth increased with increasing gestational age, for example, between 37 and 38 weeks' gestation (12.5 per 10,000 vs 22.5 per 10,000; P<.05). As expected, the risk of infant death following delivery gradually decreased as pregnancies approached term gestation. Week-by-week differences were statistically significant (P<.05) between 32 and 36 weeks with decreasing risk of infant death at advancing gestational ages. The composite risk of stillbirth and infant death associated with an additional week of pregnancy had a significant increase from 37 to 38 weeks' gestation (43.9 per 10,000 vs 59.2 per 10,000; P<.05). At 37 weeks' gestation, the relative risk of mortality was statistically significantly lower with immediate delivery as compared with expectant management (relative risk, 0.87; 95% confidence interval, 0.77-0.99).

CONCLUSION

Our results suggest that fetal/infant death risk is minimized at 37 weeks' gestation; however, individual maternal and fetal characteristics must also be taken into account when determining the optimal timing of delivery for twin pregnancies.

The risk of infant and fetal death by each additional week of expectant management in intrahepatic cholestasis of pregnancy by gestational age

OBJECTIVE

The objective of the study was to characterize the risk of infant and fetal death by each additional week of expectant management vs immediate delivery in pregnancies complicated by cholestasis.

STUDY DESIGN

This was a retrospective cohort study of 1,604,386 singleton, nonanomalous pregnancies of women between 34 and 40 weeks' gestation with and without intrahepatic cholestasis of pregnancy (ICP) in the state of California during the years of 2005-2008. International Classification of Diseases, 9th version, codes and linked hospital discharge and vital statistics data were utilized. For each week of gestation, the following outcomes were assessed: the risk of stillbirth, the risk of delivery (represented by the risk of infant death at a given week of gestation), and the composite risk of expectant management for 1 additional week. Composite risk combines the risk of stillbirth at this gestational age week plus the risk of infant death if delivered at the subsequent week of gestation.

RESULTS

Among women with ICP, the mortality risk of delivery is lower than the risk of expectant management at 36 weeks' gestation (4.7 vs 19.2 per 10,000). The risk of expectant management remains higher than delivery and continues to rise by week of gestation beyond 36 weeks. The risk of expectant management in women with ICP reaches a nadir at 35 weeks (9.1 per 10,000; 95% confidence interval, 1.4-16.9) and rises at 36 weeks (19.2 per 10,000; 95% confidence interval, 7.6-30.8).

CONCLUSION

Among women with ICP, delivery at 36 weeks' gestation would reduce the perinatal mortality risk as compared with expectant management. For later diagnoses, this would also be true at gestational ages beyond 36 weeks. Timing of delivery must take into account both the reduction in stillbirth risk balanced with the morbidities associated with preterm delivery.

A. Holland A, Badawi N. The impact of surgery on the developmental status of late preterm infants - a cohort study

AIMS

Despite increasing evidence in the literature regarding the impact of late prematurity on subsequent developmental impairment, the developmental outcome of late preterm infants who undergo major surgery remains unclear. The aim of this study therefore was to determine the developmental outcome for a cohort of late preterm surgical population.

METHODS

Late preterm infants with a gestational age from 34-36 weeks inclusive who were enrolled in the state-wide prospective Development After Infant Surgery (DAISy) study and who had undergone non-cardiac major surgery within the first ninety days of life were eligible for inclusion. Infants were assessed at one and three years of ages.

RESULTS

Forty-six infants were enrolled in the study, of which 38 infants had a complete developmental assessment at one year of age. Of these infants, late preterm infants scored significantly lower than the standardized norms of the assessment on the expressive language and gross motor subscales. At three years of age 26 infants were reassessed: late preterm infants who underwent major surgery only scored significantly lower than the standardized norms on the cognitive subscale (p less than 0.001).

CONCLUSIONS

These data provide the evidence that late preterm infants who undergo major non-cardiac surgery are at risk of developmental impairment and consideration should be given to enrolling this cohort in multi-disciplinary developmental follow-up clinics.

Cerebral palsy among children born moderately and late preterm

OBJECTIVE

To compare the incidence of and risk factors for cerebral palsy (CP) in moderately preterm (MP) (32(+0)-33(+6) weeks) and late preterm (LP) (34(+0)-36(+6) weeks) infants with those in very preterm (VP) (<32(+0) weeks) and term infants (≥37 weeks).

METHODS

The national register study included all live-born infants in Finland from 1991 to 2008. Infants who died before the age of 1 year, had any major congenital anomaly, or had missing data were excluded. A total of 1 018 302 infants were included in the analysis and they were analyzed in 4 subgroups (VP, MP, LP, and term) and 3 time periods (1991-1995, 1996-2001, and 2002-2008).

RESULTS

By the age of 7 years, 2242 children with CP were diagnosed (0.2%). CP incidence was 8.7% in the VP, 2.4% in the MP, 0.6% in the LP, and 0.1% in the term group. The risk of CP was highest in the study period 1991-1995 in all groups. Factors predictive of an increased CP risk in the MP and LP groups included resuscitation at birth (odds ratio 1.60; 95% CI 1.01-2.53 and 1.78; 1.09-2.90), antibiotic treatment during the first hospitalization (1.63; 1.08-2.45 and 1.67; 1.13-2.44), 1-minute Apgar score <7 (1.70; 1.15-2.52 and 1.80; 1.21-2.67) and intracranial hemorrhage (7.18; 3.60-14.3 and 12.8; 5.58-29.2).

CONCLUSIONS

The incidence of CP is higher in LP and MP infants compared with term infants. There is a nonlinear decrease in incidence over time and with increasing gestational age.

Mild prematurity, proximal social processes, and development

OBJECTIVE

To elucidate the role of gestational age in determining the risk of poor developmental outcomes among children born late preterm (34-36 weeks) and early term (37-38 weeks) versus full term (39-41 weeks) by examining the contribution of gestational age to these outcomes in the context of proximal social processes.

METHODS

This was an analysis of the Canadian National Longitudinal Survey of Children and Youth. Developmental outcomes were examined at 2 to 3 (N= 15099) and 4 to 5 years (N= 12302). The sample included singletons, delivered at 34 to 41 weeks, whose respondents were their biological mothers. Multivariable modified Poisson regression was used to directly estimate adjusted relative risks (aRRs). We assessed the role of parenting by using moderation analyses.

RESULTS

In unadjusted analyses, children born late preterm appeared to have greater risk for developmental delay (relative risk = 1.26; 95% confidence interval [CI], 1.01 to 1.56) versus full term. In adjusted analyses, results were nonsignificant at 2 to 3 years (late preterm aRR = 1.13; 95% CI, 0.90 to 1.42; early term aRR = 1.11; 95% CI, 0.96 to 1.27) and 4 to 5 years (late preterm aRR = 1.06; 95% CI, 0.79 to 1.43; early term aRR = 1.03; 95% CI, 0.85 to 1.25). Parenting did not modify the effect of gestational age but was a strong predictor of poor developmental outcomes.

CONCLUSIONS

Our findings show that, closer to full term, social factors (not gestational age) may be the most important influences on development.

Does gestational diabetes mellitus affect respiratory outcome in late-preterm infants?

BACKGROUND

Both gestational diabetes mellitus (GDM) and late-preterm delivery at 34-36 weeks' gestation are independently associated with neonatal respiratory complications, but it is unknown whether their combination increases further its risk. We therefore appraised the independent effect of GDM on the respiratory outcome of late-preterm infants.

METHODS

In a retrospective cohort study, respiratory outcome of 911 infants delivered at 34-36 weeks' gestation between 1 January 2009 and 30 August 2012 from mothers with GDM (study group, n=130) was compared with infants delivered at the same gestation by mothers without GDM (control group, n=781).

RESULTS

The study group had significantly higher incidence of transient tachypnoea of newborn (TTN, p=0.02) and air leak (p=0.012), and required more respiratory support, including oxygen, continuous positive airway pressure (CPAP), mechanical ventilation and neonatal intensive care, with a longer length of hospital stay, but not duration on respiratory support. On logistic regression analysis, GDM is an independent risk factor for TTN (aOR=1.5, 95% C.I.1.0-2.4), CPAP (aOR=2.37, 95% C.I. 1.05-4.89), mechanical ventilation (aOR=4.02 95% C.I. 1.57-10.32) and neonatal intensive care (aOR 1.83, 95% C.I. 1.05-3.87).

CONCLUSIONS

Our results demonstrated an independent effect of GDM on the risk of severe respiratory complications in late-preterm infants. Additional close monitoring and timely intervention are necessary in the management of these infants.

Short-term respiratory outcomes in late preterm infants

Objective

To evaluate short-term respiratory outcomes in late preterm infants (LPI) compared with those of term infants (TI).

Methods

A retrospective study conducted in a single third level Italian centre (2005–2009) to analyse the incidence and risk factors of composite respiratory morbidity (CRM), the need for adjunctive therapies (surfactant therapy, inhaled nitric oxide, pleural drainage), the highest level of respiratory support (mechanical ventilation – MV, nasal continuous positive airway pressure – N-CPAP, nasal oxygen) and the duration of pressure support (hours in N-CPAP and/or MV).

Results

During the study period 14,515 infants were delivered. There were 856 (5.9%) LPI and 12,948 (89.2%) TI. CRM affected 105 LPI (12.4%), and 121 TI (0.9%), with an overall rate of 1.6%. Eighty-four LPI (9.8%) and 73 TI (0.56%) received respiratory support, of which 13 LPI (1.5%) and 16 TI (0.12%) were ventilated. The adjusted OR for developing CRM significantly increased from 3.3 (95% CI 2.0-5.5) at 37 weeks to 40.8 (95% CI 19.7-84.9%) at 34 weeks. The adjusted OR for the need of MV significantly increased from 3.4 (95% CI 1.2-10) at 37 weeks to 34.4 (95% CI 6.7-180.6%) at 34 weeks. Median duration of pressure support was significantly higher at 37 weeks (66.6 h vs 40.5 h). Twin pregnancies were related to a higher risk of CRM (OR 4.3, 95% CI 2.6-7.3), but not independent of gestational age (GA). Cesarean section (CS) was associated with higher risk of CRM independently of GA, but the OR was lower in CS with labour (2.2, 95% CI 1.4-3.4 vs 3.0, 95% CI 2.1-4.2).

Conclusions

In this single third level care study late preterm births, pulmonary diseases and supportive respiratory interventions were lower than previously documented. LPI are at a higher risk of developing pulmonary disease than TI. Infants born from elective cesarean sections, late preterm twins in particular and 37 weekers too might benefit from preventive intervention.

[Home care of premature rupture of membranes prior to 37 weeks' gestation]

OBJECTIVE

To compare maternal and perinatal outcome according to gestational age at delivery and length of latency period in a group of patients with preterm premature rupture of membranes. To propose and evaluate an antenatal protocol of home care in a selected group of them.

PATIENTS AND METHODS

Inclusion criteria was a delivery in our maternity related to a rupture of membranes prior to 37 week's gestation. Expectant management was applied. Home care management was proposed for patients hospitalised at least 5 days and meeting strict criteria. Maternal-fetal clinical monitoring was performed daily and biological and ultrasound monitoring weekly until 37 or 38 week's gestation.

RESULTS

We included 222 patients. There was a significant increase in perinatal complications for neonates before 36 week's gestation. Maternal and perinatal outcomes were not influenced by the latency period. In the overall patients, 44 were hospitalised at least 5 days and 9 could return at home. It seems that there was no difference concerning maternal and fetal complications between home care and hospitalized patients.

DISCUSSION AND CONCLUSION

In preterm premature rupture of membranes after 34 week's gestation, monitored expectant management can reduce prematurity complications without increasing infectious complications. After an initial hospitalization, for a small proportion of them, home care seems possible without increasing maternal and fetal morbidity.

Neonatal morbidity associated with late preterm and early term birth: the roles of gestational age and biological determinants of preterm birth

BACKGROUND

The aim of this study was to elucidate the role of gestational age in determining the risk of neonatal morbidity among infants born late preterm (34-36 weeks) and early term (37-38 weeks) compared with those born full term (39-41 weeks) by examining the contribution of gestational age within the context of biological determinants of preterm birth.

METHODS

This was a retrospective cohort study. The sample included singleton live births with no major congenital anomalies, delivered at 34-41 weeks of gestation to London-Middlesex (Canada) mothers in 2002-11. Data from a city-wide perinatal database were linked with discharge abstract data. Multivariable models used modified Poisson regression to directly estimate adjusted relative risks (aRRs). The roles of gestational age and biological determinants of preterm birth were further examined using mediation and moderation analyses.

RESULTS

Compared with infants born full term, infants born late preterm and early term were at increased risk for neonatal intensive care unit triage/admission [late preterm aRR=6.14, 95% confidence interval (CI) 5.63, 6.71; early term aRR=1.54, 95% CI 1.41, 1.68] and neonatal respiratory morbidity (late preterm aRR=6.16, 95% CI 5.39, 7.03; early term aRR=1.46, 95% CI 1.29, 1.65). The effect of gestational age was partially explained by biological determinants of preterm birth acting through gestational age. Moreover, placental ischaemia and other hypoxia exacerbated the effect of gestational age on poor outcomes.

CONCLUSIONS

Poor outcomes among infants born late preterm and early term are not only due to physiological immaturity but also to biological determinants of preterm birth acting through and with gestational age to produce poor outcomes.

ADHD and learning disabilities in former late preterm infants: a population-based birth cohort

BACKGROUND AND OBJECTIVE

Previous studies suggest that former late preterm infants are at increased risk for learning and behavioral problems compared with term infants. These studies have primarily used referred clinical samples of children followed only until early school age. Our objective was to determine the cumulative incidence of attention deficit/hyperactivity disorder (ADHD) and learning disabilities (LD) in former late preterm versus term infants in a population-based birth cohort.

METHODS

Subjects included all children born 1976 to 1982 in Rochester, MN who remained in the community after 5 years. This study focused on the comparison of subjects in 2 subgroups, late preterm (34 to <37 weeks) and term (37 to <42 weeks). School and medical records were available to identify individuals who met research criteria for ADHD and LD in reading, written language, and math. The Kaplan-Meier method was used to estimate the cumulative incidence of each condition by 19 years of age. Cox models were fit to evaluate the association between gestational age group and condition, after adjusting for maternal education and perinatal complications.

RESULTS

We found no statistically significant differences in the cumulative incidence of ADHD or LD between the late preterm (N = 256) versus term (N = 4419) groups: ADHD (cumulative incidence by age 19 years, 7.7% vs 7.2%; P = .84); reading LD (14.2% vs 13.1%; P = .57); written language LD (13.5% vs 15.7%; P = .36), and math LD (16.1% vs 15.5%; P = .89).

CONCLUSIONS

These data from a population-based birth cohort indicate that former late preterm infants have similar rates of LD and ADHD as term infants.

Trends in the distribution of gestational age and contribution of planned births in New South Wales, Australia

BACKGROUND

There is concern that the rate of planned births (by pre-labour caesarean section or induction of labour) is increasing and that the gestation at which they are being conducted is decreasing. The aim of this study was to describe trends in the distribution of gestational age, and assess the contribution of planned birth to any such changes.

METHODS

We utilised the New South Wales (NSW) Perinatal Data Collection to undertake a population-based study of all births in NSW, Australia 1994-2009. Trends in gestational age were determined by year, labour onset and plurality of birth.

RESULTS

From 1994-2009, there was a gradual and steady left-shift in overall distribution of gestational age at birth, with a decline in the modal gestational age from 40 to 39 weeks. For singletons, there was a steady but significant reduction in the proportion of spontaneous births. Labour inductions increased in the proportion performed, with a gradual and changing shift in the distribution from a majority at 40 weeks to an increase at both 37-39 weeks and 41 weeks gestation. The proportion of pre-labour caesareans also increased steadily at each gestational age and doubled since 1994, with most performed at 39 weeks in 2009 compared with 38 weeks up to 2001.

CONCLUSIONS

Findings suggest a changing pattern towards births at earlier gestations, fewer births commencing spontaneously and increasing planned births. Factors associated with changing clinical practice and long-term implications on the health and well-being of mothers and babies should be assessed.

Risks associated with delivering infants 2 to 6 weeks before term--a review of recent data

BACKGROUND

There is an increasing trend towards delivery before 39 weeks of gestational age. The short- and long-term effects of early delivery on the infant have only recently received scientific attention.

METHODS

Selective review of the literature

RESULTS

Delivery at any time before 39 weeks is associated with significantly higher infant mortality and with an increase of the risk of impairments after birth from 8% to 11%. The increase in risks of various kinds is disproportionately more pronounced the earlier the child is delivered. For example, the risk of needing respiratory support or artificial ventilation after birth increases from 0.3% with delivery at 39-41 weeks of gestational age to 1.4% at 37 weeks and 10% at 35 weeks, while the risk of death or neurological complications increases from 0.15% at 39-41 weeks of gestation to 0.66% at 35 weeks. Delivery at 34.0 to 36.6 weeks of gestation also has long-term effects. Compared to delivery at term, the frequency of cerebral palsy rises threefold, from 0.14% to 0.43%; the risk of death in early adulthood rises by about half, from 0.046 to 0.065%; and the risk of dependence on government benefits in early adulthood also rises by about half, from 1.7% to 2.5%.

CONCLUSION

Studies from the USA have shown that the number of medically indicated deliveries before 39 weeks can be lowered by 70% to 80% through consistently applied measures for quality improvement. If similar results could be achieved in Germany, the iatrogenic complications of delivery would become less common in this country as well.

Increasing rates of prematurity and epidemiology of late preterm birth

Preterm birth rates in Australia have risen in the last two decades, mostly accounted for by the rise in late preterm births. Late preterm births (34-36 weeks) comprise 70% of all preterm births, which translates to approximately 16,000 births annually in Australia. The precise causes for this trend are unclear; however, possible aetiologies include increasing maternal age, increased use of artificial reproductive technologies and increased multiple births. Compared with term-born children, late preterm children not only have increased mortality and in-hospital morbidity including respiratory difficulties, but also long-term cognitive, school performance, behaviour and psychiatric problems. The potential public health and educational burden of late preterm birth is considerable. More research is required in this area to understand the risk factors for late preterm birth and to help identify those children at highest risk of developmental deficits.

NEONATAL OUTCOMES FOLLOWING LATE PRETERM BIRTH

It is well recognised that birth before 32 weeks of gestation is associated with substantial neonatal morbidity and mortality and these risks have been extensively reported. The focus of perinatal research for many years has therefore been very preterm and extremely preterm delivery, since the likelihood and severity of adverse neonatal outcomes are highest within this group. In contrast, until recently, more mature preterm infants have been understudied and indeed, almost ignored by researchers.

Prospective risk of late stillbirth in monochorionic twins: a regional cohort study

OBJECTIVE

Monochorionic (MC) pregnancies are routinely delivered electively at late preterm gestation with the aim of avoiding stillbirth at term. The aim of this study was to evaluate the prospective risk of late stillbirth in a large regional cohort of twin pregnancies of known chorionicity.

METHODS

This was a retrospective study of all twin pregnancy births of known chorionicity between 2000 and 2009 from a large regional cohort consisting of nine hospitals. Prospective risk was calculated per 1000 fetuses rather than pregnancies, as each twin pregnancy had two gestations at risk of stillbirth.

RESULTS

A total of 3005 twin pregnancies delivered after 26 weeks' gestation in the Southwest Thames Obstetric Research Collaborative. The total risk of stillbirth after 26 weeks in MC twins (19.1 per 1000 fetuses) was significantly higher than in dichorionic (DC) twins (6.5 per 1000 fetuses), with an odds ratio (OR) of 2.97 (95% CI, 1.71-5.18). The risk of stillbirth in MC twins did not change significantly between 26 weeks (1.8 per 1000 fetuses) and 36 weeks (3.4 per 1000 fetuses), with an OR of 1.85 (95% CI, 0.3-13.2). The equivalent figures for DC twins were 0.6 per 1000 fetuses and 2.1 per 1000 fetuses, respectively (OR, 3.4 (95% CI, 0.9-13.2)).

CONCLUSIONS

The risk of stillbirth in MC twins does not appear to increase significantly near term. This may be due to a policy of routine surveillance and elective delivery from 36 weeks. The data do not support a policy of elective delivery before 36 weeks' gestation in MC pregnancies.