Perinatal outcomes of a large cohort of extremely low gestational age infants (twenty-three to twenty-eight completed weeks of gestation),☆☆,,★★

https://doi.org/10.1016/S0022-3476(05)82015-3Get rights and content

Abstract

Objectives: To determine gestational age (GA)-specific mortality rates; the effects of GA, birth weight, sex, and multiple gestation on mortality rates; short-term morbidity for infants born at 23 to 28 weeks GA; and impairment rates at a corrected chronologic age of 18 months for those born at 23 to 25 weeks GA. Methods: A data base analysis was performed with a linked obstetric and a neonatal database. GA was determined by obstetric data and confirmed by early ultrasonography (available in 88%) on all births <30 weeks GA at British Columbia's tertiary perinatal center from 1983 to 1989. Results: Of 1024 births occurring between 23 and 28 weeks GA, 911 were live born. The mortality rate decreased with increasing GA: 84% at 23 weeks; 57% at 24 weeks; 45% at 25 weeks; 37% at 26 weeks; 23% at 27 weeks; and 13% at 28 weeks GA. For each GA, mortality rate versus birth weight plots showed a decreasing mortality rate with increasing birth weight, except for infants who were large for GA. Male infants had a higher mortality rate than female infants (odds ratio, 1.8; confidence interval, 1.4 to 2.5). Twins fared worse than singletons with a decreasing effect from 24 weeks GA (odds ratio, 10.3) to no effect at 28 weeks GA. The median number of days supported by mechanical ventilation and the length of stay in the neonatal intensive care unit decreased markedly with increasing GA. Eighteen-month outcome of survivors between 23 and 25 weeks GA with 93% follow-up rate revealed an overall impairment rate of 36%, but 6 of the 9 surviving 23-week infants had major impairments. Conclusions: The GA-specific perinatal outcome results of this large cohort provide information to assist in perinatal management decision making and for counseling parents prenatally. (J PEDIATR 1994;125:952-60)

Section snippets

Institution

The Grace/Children's Hospital complex serves a population of 3 million persons with approximately 45,000 births per year. The Grace Hospital has between 7000 and 8000 deliveries each year, one third of which are high-risk obstetric referrals. About 700 to 800 infants are admitted annually to the NICU in British Columbia's Children's Hospital, of whom 140 are outborn. The neonatal resuscitation team from the NICU attends all high risk deliveries in Grace Hospital. Infants in the NICU no longer

Study population

After obstetric review of the hospital records of all patients identified to have delivered live-born or stillborn infants at or less than 30 weeks GA in the Grace Hospital, it was found that 1024 infants born to 920 mothers had validated GAs between 23 and 28 weeks, inclusive, and they formed the study group. There were no survivors born before 23 completed weeks of gestation. Fetal ultrasonographic data from the first 24 weeks of gestation were available for 904 (88%) of the study infants. Of

DISCUSSION

These outcome data on infants born at extremely low GAs are based on the largest such population published to date. Exhaustive efforts were made to establish GA as accurately as possible and to overcome the shortcomings of previous studies. Our validation procedure for GA revealed a consistent tendency among clinicians to overestimate GA at these critically short GAs; on review, a correction was required in 34%, the error usually being an overestimate. There may be two reasons for this

References (42)

  • M Hack et al.

    Outcomes of extremely low-birth- weight infants between 1982 and 1988

    N Engl J Med

    (1989)
  • EL Hoffman et al.

    Birth weight less than 800 grams: changing outcomes and influences of gender and gestation number

    Pediatrics

    (1990)
  • Victorian Infant Collaborative Study Group

    Improvement of outcome for infants of birth weight under 1000 g

    Arch Dis Child

    (1991)
  • DL Phelps et al.

    28-Day survival rates of 6676 neonates with birth weights of 1250 grams or less

    Pediatrics

    (1991)
  • NW Svenningsen et al.

    Neonatal outcome of extremely small low birthweight liveborn infants below 901 g in a Swedish population

    Acta Paediatr Scand

    (1989)
  • Z Vekerdy-Lakatos et al.

    Infants weighing 1000 g or less at birth

    Acta Paediatr Scand Suppl

    (1989)
  • MC Allen et al.

    The limit of viability: neonatal outcome of infants born at 22 to 25 weeks' gestation

    N Engl J Med

    (1993)
  • G. Eg-Andersen

    Prediction of outcome in 164 infants born after 24 to 28 weeks gestation

    Acta Paediatr Scand Suppl

    (1989)
  • M Herschel et al.

    Survival of infants born at 24 to 28 weeks' gestation

    Obstet Gynecol

    (1982)
  • W Kitchen et al.

    Cesarean section or vaginal delivery at 24 to 28 weeks' gestation: comparison of survival and neonatal and two-year morbidity

    Obstet Gynecol

    (1985)
  • AGS Philip et al.

    Neonatal mortality risk for the eighties: the importance of birth weight/gestational age groups

    Pediatrics

    (1981)
  • Cited by (141)

    • Maternal and Perinatal Outcomes of Pregnancies Delivered at 23 Weeks' Gestation

      2015, Journal of Obstetrics and Gynaecology Canada
      Citation Excerpt :

      The rate of survival was 10.8% (25/232) when antepartum stillbirths were excluded and 12.8% (5/39) in centres that offered fetal heart rate monitoring at 23 weeks’ gestation. Previous studies have noted a wide range of survival rates for all births (including stillbirths) at this gestation, ranging from 0% to 37%.5–7,9–12,14,17–19,36,37 Some studies present survival rates for live births only, ranging from 0% to 53%.5,7,10,11,14,16–18,20,36,37,47

    • The Effect of Maternal Age on Adverse Birth Outcomes: Does Parity Matter?

      2010, Journal of Obstetrics and Gynaecology Canada
    View all citing articles on Scopus

    From the Departments of Pediatrics and of Obstetrics and Gynecology, Research Support Services, University of British Columbia, British Columbia's Children's Hospital and Grace Maternity Hospital, Vancouver, British Columbia, Canada.

    ☆☆

    Supported by British Columbia Health Research Foundation grant No. 134 (90-92).

    Reprint requests: Emily W. Y. Ling, British Columbia's Children's Hospital, Room 1N1, 4480 Oak St., Vancouver, British Columbia V6H 3V4, Canada.

    ★★

    0022-3476/94/$3.00 + 0 9/23/58440

    View full text