- Trends Over Time
- Preterm Births in Wales
- Outcome by Gestation and Birthweight
- Homebirths in Wales
Trends over Time
There were 33,527 registrable births (livebirths and stillbirths) in 2015, to mothers resident in Wales at the time of birth (Figure 1). This is similar to registrable births in 2013 and 2014 but represents a 13% increase since 2002 but a decrease from 2010 (Table A1). The observed trend in number of births follows a similar pattern in Scotland1.
Of these registrable births 93.1% occurred in Welsh hospitals, 2.7% were born in hospitals outside Wales, 2.8% were homebirths and 1.4% were elsewhere or unknown. The average age of mothers at childbirth in Wales was 28.8 years (SD 5.7), compared to 28.6 years (SD 5.8) in 2014. Overall, 4.56% of births were to women aged under 20 years and 16.83% were to women aged 35 or over (Table A2). Comparable rates in 2014 were 4.2% and 13.4% respectively.
The distribution of births according to social deprivation quintiles varied by Health Board (Table A2 (2)). Overall in Wales, 25.43% of births occurred to women resident in the most deprived quintile. This rate varied from 5.02% in Powys Teaching Health Board, to 34.11% in Cwm Taf Health Board (Table A2(2)).
In total, there were 31,558 registrable births in Welsh hospitals, of which 1.1% were to non-Welsh residents.
Figure 1: Total number of births in Wales: 1994 to 2015
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Source NCCHD and AWPS/MBRRACE-UK
Preterm births in Wales
Between 2011 and 2015, there were 12,810 registrable preterm (< 37 weeks’ gestation) births (Table A3), which is 7.42% of all registrable births during this period.
Figure 2 shows preterm birth rates by gestation bands, which suggests that there has been minimal changes in rates over the last ten years, with the extreme preterm, (less than 28 weeks’ gestation), birth rates showing the least variation over time.
Table A3 documents the preterm birth rates by deprivation quintiles, and shows minimal variation in the rates of extreme preterm births across the deprivation quintiles. However, the rates of preterm birth after 28 weeks’ gestation are higher in the most deprived quintile (Table A3).
A number of risk factors are known to contribute to preterm birth, including in vitro fertilisation, multiple pregnancies, and maternal weight. Cnattingius2 noted that the risk of spontaneous extremely preterm delivery ( or equal to 30) and that the risks of medically indicated preterm deliveries increased with BMI among overweight and obese women. Welsh data on maternal weight is not accurately collected, and thus we are not able to report it here.
Table A4 shows preterm birth by Health Board of residence in Wales: 2011 to 2015 and 2006 to 2010. Rates vary slightly between regions.
Figure 2: Preterm birth rates by gestational age per 1,000 registrable births in Wales: 1994 to 2015
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Outcome by Gestation and Birthweight
Improvements in perinatal care, antenatal corticosteroids, surfactant therapy and advances in neonatal care have all resulted in improved outcome of very preterm infants. In Wales, the survival figures compare favourably with UK and international figures3-5.
The most significant improvement has been observed in the infants born at 24 and 25 weeks’ gestation. In Wales, in 1994, the survival up to 1 year was 19% for 24 weeks’ and 46% for 25 weeks’ gestation6. In 2014, the survival up to one month after a livebirth was 58.6% for 24 weeks’ gestation and 76.2% for 25 weeks’ gestation. In 2014, the survival up to one year after a livebirth was 40.00% for 24 weeks’ gestation and 69.57% for 25 weeks’ gestation (Table A5 (2)). In 2015, the survival up to one month after a livebirth was 71.43% for 24 weeks’ gestation and 87.10% for 25 weeks’ gestation (Table A5). Survival up to one year after a livebirth for 2015 will be published in next year’s annual report.
In 2014, there were five infants born alive between 20-22 weeks’ gestation, none surviving to one year of age. The survival figures for infants born at 22 weeks’ gestation have remained similar. Between 2004 and 2008, two of the twenty-one infants that were born alive at 22 weeks’ gestation survived to one year; between 2010 and 2014, none of the 19 infants that were born alive at 22 weeks survived to one year of age (Table A6(2)). The survival figures for infants born at 23 weeks’ gestation have remained similar. Between 2004 and 2008 14.3% of the infants born alive at 23 weeks gestation survived to one year of age; between 2010 to 2014 16.44% of the infants that were born alive at 23 weeks’ gestation survived to one year of age. (Table A6 (2)). Survival figures are similar to the Epicure 2006 data; survival of liveborn infants to discharge from hospital was 2% at 22 weeks’ gestation, 19% at 23 weeks’ gestation, 40% at 24 weeks’ gestation, 66% at 25 weeks’ gestation7.
One-year survival rates for preterm births increased significantly with gestational age from 23 weeks. One-year survival rates are 48.32% at 24 weeks, 66.12% at 25 weeks, 76.02% at 26 weeks’ and 89.00% at 27 weeks’ gestation for the five years 2010-2014 (Table A6).
Birthweight specific survival in Wales in 2015 and in the five years 2011-2015 are shown in Tables A7 and A8. In 2014, none of the 12 infants that were born alive weighing less than 500g survived up to one year of age. In 2015, one of the 12 infants that were born alive weighing less than 500g survived up to one month of age.
Homebirths in Wales
Homebirths are offered to low-risk women in the UK. The homebirth figures presented in Figure 3 remain at approximately 3% for the last three years, having reached a peak in 2009 at 3.69%.
Figure 3: Homebirths in Wales: 1994 to 2015
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For data on rates of planned and unplanned homebirths prior to 2013 please see the AWPS annual report for 2012 which reports using data from unit coordinators in Wales.
1. REGISTRAR GENERAL of BIRTHS DEATHS AND MARRIAGES for SCOTLAND. SCOTLAND’S POPULATION 2011. The Registrar General’s Annual Review of Demographic Trends. 157th Edition ‘Available at:’
http://www.gro-scotland.gov.uk/files2/stats/annual-review-2011/rgar-2011.pdf Accessed August 2013.
2. Cnattingius S, Villamor E, Johansson S, Edstedt Bonamy AK, Persson M, Wikstrom AK, et al. Maternal obesity and risk of preterm delivery. JAMA : the journal of the American Medical Association 2013;309(22):2362-70
3. Field DJ, Dorling JS, Manktelow BN, Draper ES. Survival of extremely premature babies in a geographically defined population: prospective cohort study of 1994-9 compared with 2000-5. BMJ 2008;336(7655):1221-3
4. Larroque B, Breart G, Kaminski M, Dehan M, Andre M, Burguet A, et al. Survival of very preterm infants: Epipage, a population based cohort study. Arch Dis Child Fetal Neonatal Ed 2004 89(2):F139-F44
5. Costeloe K, Hennessy E, Gibson AT, Marlow N, Wilkinson A, for the EPICure Study Group. The EPICure Study: Outcomes to Discharge from Hospital for Infants Born at the Threshold of Viability. Pediatrics 2000;106(4):659-71
6. Cartlidge PH, Stewart JH. Survival of very low birthweight and very preterm infants in a geographically defined population. Acta paediatrica 1997;86(1):105-10
7. Costeloe KL, Hennessy EM, Haider S, Stacey F, Marlow N, Draper ES. Short term outcomes after extreme preterm birth in England: comparison of two birth cohorts in 1995 and 2006 (the EPICure studies). BMJ 2012; 345 doi: http://dx.doi.org/10.1136/bmj.e7976