Risk factors for very preterm delivery out of a level III maternity unit: The EPIPAGE‐2 cohort study

Abstract

Background Regionalisation programmes aim to ensure that very preterm infants are born in level III units (inborn) through antenatal referral or transfer. Despite widespread knowledge about better survival without disability for inborn babies, 10%‐30% of women deliver outside these units (outborn). Objective To investigate risk factors associated with outborn deliveries and to estimate the proportion that were probably or possibly avoidable. Methods We used a national French population‐based cohort including 2205 women who delivered between 24 and 30+6 weeks in 2011. We examined risk factors for outborn delivery related to medical complications, antenatal care, sociodemographic characteristics and living far from a level III unit using multivariable binomial regression. Avoidable outborn deliveries were defined by pregnancy risk (obstetric history, antenatal hospitalisation) and time available for transfer. Results 25.0% of women were initially booked in level III, 9.1% were referred, 49.8% were transferred, and 16.1% had outborn delivery. Risk factors for outborn delivery were gestational age <26 weeks (adjusted relative risk (aRR) 1.37, 95% confidence interval (CI) 1.13, 1.66), inadequate antenatal care (aRR 1.39, 95% CI 1.10, 1.81), placental abruption (aRR 1.66, 95% CI 1.27, 2.17), and increased distance to the closest level III unit ((aRR 2.79, 95% CI 2.00, 3.92) in the 4th versus 1st distance quartile). Among outborn deliveries, 16.7% were probably avoidable, and 25.6% possibly avoidable, which could increase the proportion of inborn deliveries between 85.9% and 92.9%. Avoidable outborn deliveries were mainly associated with gestational age, intrauterine growth restriction, preterm premature rupture of membranes, and haemorrhage, but not distance. Conclusions Our study identified some modifiable risk factors for outborn delivery; however, when regionalised care relies heavily on antenatal transfer, as it does in France, only some outborn deliveries may be prevented. Earlier referral of high‐risk women will be needed to achieve full access to tertiary care.

Survival and neurodevelopmental impairment of outborn preterm infants at 5.5 years of age: an EPIPAGE-2 prospective, matched study using multiple imputation

“…These results are consistent with other studies that suggest benefits of antenatal transfer are greater with decreasing GA 1 7 35. Moreover, while over 80% of children were inborn and a regionalised system of care has existed in France since the 1990s,23 there remain a subset of outborns that could potentially be avoided 34…”

“…When we looked at only the 24–27 week infants, the adjusted estimate showed improved outcomes for inborns. Analyses performed by week of GA suggested a trend favouring inborn infants at lower GAs, although not at the GAs of 24 and 25 weeks for which attitudes in France in 2011 were known to be more mixed 33 34. These results are consistent with other studies that suggest benefits of antenatal transfer are greater with decreasing GA 1 7 35.…”

“…33 34 These results are consistent with other studies that suggest benefits of antenatal transfer are greater with decreasing GA. 1 7 35 Moreover, while over 80% of children were inborn and a regionalised system of care has existed in France since the 1990s, 23 there remain a subset of outborns that could potentially be avoided. 34 At 2 years of age, there were no differences in outcomes between our inborn and outborn groups, similar to two smaller Australian studies that looked at infants of 23-28 weeks' GA 11 and 23-25 weeks' GA. 7 Similarly, there were no differences in neonatal outcomes other than for necrotising enterocolitis which was of borderline statistical significance (p=0.043) and may be a chance finding due to multiple testing; this warrants further investigation.…”

Measuring severe neonatal morbidity using hospital discharge data in France

“…In France, levels of care are defined as follows: 1 (care for low-risk newborns, no neonatal unit), 2A and 2B (intermediate special care units) and 3 (neonatal intensive care). 25 We then compared lethality and length of hospital stay (LOS) amongst births with NOAI morbidity codes in outlier versus other hospitals to test whether over-coding might explain outlying values, as done in previous research to explore regional differences in Medicare diagnostic codes. 26 We also compared individual NAOI components to identify morbidities which might be particularly affected by coding variability.…”

“…These analyses were stratified by level of neonatal care to account for referral patterns and expected higher rates of severe morbidity in more specialised hospitals. In France, levels of care are defined as follows: 1 (care for low‐risk newborns, no neonatal unit), 2A and 2B (intermediate special care units) and 3 (neonatal intensive care) 25 …”