(Acta Paediatr Jpn 1992; 34: 61 2
- 616)
Survival Rate of Extremely Low Birthweight Infants and its Effect on the Amendment of the Eugenic Protection Act in Japan
'Maternal and Perinatal Center, Tokyo Women's Medical College, Tokyo; 'Subcommittee for Neonatal Surveillance, Committee of Newborn Infants, Japan Pediatric Society, Tokyo, Japan
Because of the increasing survival rate of extremely low birthweight infants in recent years, the viability limit in the Eugenic Protection Act in Japan was amended from 24 to 22 completed weeks of gestation. The Japan Pediatric Society's survey on the outcome of infants born in 1990 focused on infants born before 24 weeks gestation and less than 500 g. The survival rates of infants born in 23,22 and before 22 weeks gestation overall at 511 hospitals throughout Japan were 431118 (36%), 3/36 (8%) and 0/8 (OVo), respectively. Of 16 infants, none weighing less than 400 g at birth survived but 16 (12%)of 50 infants between 400 and 499 g survived. Upto-date statistical data is essential to the amendment of the concept of viability and subsequent ethical decision-making on extremely low birthweight infants. Key Words Viability, Extremely low birthweight infant, Abortion law, Medical ethics, Neonatal mortality rate
Introduction In the Encyclopedia of Bioethics, Reich has stated that 'the emerging bioethics in medicine is inevitable in this era when the rapid advancement of modem science creates new conflicts between old and new concepts of life and death' 111. Especially in perinatal and neonatal medicine, where birth and death take place at the same time, out-of-date concepts about the viability of fetuses and premature infants create considerable confusion and problems [2-41. The advancement of perinatal and neonatal medicine is so rapid that ethical decisions based on Received July 17, 1992 Correspondence address: Hiroshi Nishida, M.D., Maternal and Perinatal Center, Tokyo Women's Medical College, 8- 1 Kawadacho, Shinjuku-ku. Tokyo 212, Japan.
medical knowledge should be revised as medical capabilities progress [5,6]. In 1991, the viability limit of fetal gestational age in the Eugenic Protection Act in Japan was amended from 24 weeks to 22 weeks because of the increasing number of infants surviving after less than 24 weeks gestation [7, 81. This article summarizes the most recent statistics on extremely low birthweight (ELBW) infants and their effect on the recent amendment to the Eugenic Protection Act in Japan.
Subjects and Method At the end of January 1991, the Subcommittee for Neonatal Surveillance of the Committee of Newborn Infants, Japan Pediatric Society, conducted a study on the outcome of neonates born in 1990 by mailing questionnaires and by tele-
Survival of extremely low birthweight infants (35) 613 Table 1. Neonatal mortality rates of infants born in 1990 and cared for at 51 1 hospitals with the facility to take care of sick neonates Birthweight (9)
No. admitted
Early neonatal death
Neonatal death
< 499 500- 999 1000-1499 1500- I999 2000-2499 2500
29
317 (43%) 15/16 (94%) 17/20 (85%) 21/25 (84%) 18/20 (90%) 20121 (95%) 11/12 (92%) 9/ 15 (60%)
of ELBW infants, and emphasizes the importance of ethical policy based on up-to-date medical achievements. The term ‘viability’does not simply mean ‘the ability to be born alive’ but does mean ‘the capability to grow and to develop normally in extrauterine environments’ [2, 81. Therefore, the discussion on viability should include the ultimate outcome of these ELBW infants from the viewpoints of physical and neurological growth and development. The incidence of major neurological sequelae, including cerebral palsy and mental retardation (IQ < 60), among 529 infants with birthweights less than 1,000g who were cared at 16 NICU in Tokyo between 1986 and 1988 and who were followed for more than 1 year was 18.0% (Table 6). When we further analyzed the follow-up data of very low birthweight infants cared for at Tokyo Women’s Medical College, only 8.8%of appropriate-for-date ELBW infants had major neurological sequelae, while 3 1.6% of light-for-date ELBW infants were handicapped (Table 7). These data allow us to speculate that
Vol. 34 No. 6 December 1992
Table 6. Incidence of neurological sequelae in infants < 1,000g in Tokyo 1986-88 Normal 428 (81%) Neurological sequelae 80 (15%) CP 30 (5.6%) MR 25 (4.7%) CP + MR 25 (4.7%) Borderline 21 (4%) Total 529 CP, cerebral palsy, MR, mental retardation.
even in these ELBW infants, prematurity per se plays a minor role in the occurrence of major sequelae, but most of their causes originated antenatally or perinatally. While there is a viability limit for ELBW infants, once they survive they should have the potential to grow and develop normally. If premature infants suffered from major sequelae, it was not because they were forced to live by modern technology in spite of their fatal destiny but because the antenatal, perinatal and postnatal management of them was inappropriate.
616 (38) Nishida and Ishizuka Table 7. Neurological Sequelae in Very Low Birthweight Infants (Tokyo Women’s Medical college 1984-89) Birthweight (9)
Light-for-date
Appropriate-for-date
Total
< 1000 1000-1499 Total
6/19 (31.6%) 4/26 (1 5.4%)
5/57 (8.8%) 2/59 (3.4%)
11/76 (14.5%) 6/85 (7.1%)
10/45 (22.2%)
7/116 (6.0%)
17/161 (10.6%)
Patients are followed for more than 1 year after estimated date of confinement.
Acknowledgements We thank members of the Committee of Newborn Infants (Chairman Dr Itsuro Yamanouchi), the Japan Neonatologist Association (President Dr Takeshi Hashimoto) and the doctors who participated in the survey for their support and co-operation.
References 1.
Reich WR. Introduction. In Reich WR ed: Encyclopedia of Bioethics. Free Press, New York. 1978, 1.
Dunn, PM. Age of fetal viability. Maternal Child Health 1985; 10: 102-104. 3. Editorial: Perinatal mortality rate-Time for a change?Lancet 1991; 337: 331-333. 4. Nishida H. Future ethical issues in neonatology: A Japanese perspective. Semin Perinatol 1987;-11:
6. 7.
8.
9.
2.
275-280. 5 . Nishida H. The viability of small premature
10.
infants and its effect on ethical decision making. Asian Med J 1989; 32: 562-567. Nishida H, Sakanoue M, Ishizuka Y. ‘How small is too small?’ in Japan 1983. Acta Paediatr Jpn 1986; 28: 195-201. Committee of Newborn Infant, Japan Society of Pediatrics. Report on the current status of NICU and neonatal mortality in Japan. J Jpn Pediatr Soc 1991; 95: 2454-2461 (in Jpn). Nishida H. The viability limit of gestation for the fetus and premature neonates. (The effect of recent amendment of Eugenic Protection Act in Japan). Asian Med J 1991; 35: 487-494. Ishizuka Y . Current conditions of NICU and mortality rate of very premature infants in Japan (Results of nationwide survey in January 1989). J Jpn Pediatr SOC1989 94: 84 1-847. Tada H. The annual report of the research on mental and physical disabilities by the Ministry of Health and Welfare. Study on improvement and evaluation of perinatal medical care system. 1989; H. Tada (ed.), Ministry of Health and Welfare, Tokyo, p 51-55.
Acta Paediatr Jpn
- 616)
Survival Rate of Extremely Low Birthweight Infants and its Effect on the Amendment of the Eugenic Protection Act in Japan
'Maternal and Perinatal Center, Tokyo Women's Medical College, Tokyo; 'Subcommittee for Neonatal Surveillance, Committee of Newborn Infants, Japan Pediatric Society, Tokyo, Japan
Because of the increasing survival rate of extremely low birthweight infants in recent years, the viability limit in the Eugenic Protection Act in Japan was amended from 24 to 22 completed weeks of gestation. The Japan Pediatric Society's survey on the outcome of infants born in 1990 focused on infants born before 24 weeks gestation and less than 500 g. The survival rates of infants born in 23,22 and before 22 weeks gestation overall at 511 hospitals throughout Japan were 431118 (36%), 3/36 (8%) and 0/8 (OVo), respectively. Of 16 infants, none weighing less than 400 g at birth survived but 16 (12%)of 50 infants between 400 and 499 g survived. Upto-date statistical data is essential to the amendment of the concept of viability and subsequent ethical decision-making on extremely low birthweight infants. Key Words Viability, Extremely low birthweight infant, Abortion law, Medical ethics, Neonatal mortality rate
Introduction In the Encyclopedia of Bioethics, Reich has stated that 'the emerging bioethics in medicine is inevitable in this era when the rapid advancement of modem science creates new conflicts between old and new concepts of life and death' 111. Especially in perinatal and neonatal medicine, where birth and death take place at the same time, out-of-date concepts about the viability of fetuses and premature infants create considerable confusion and problems [2-41. The advancement of perinatal and neonatal medicine is so rapid that ethical decisions based on Received July 17, 1992 Correspondence address: Hiroshi Nishida, M.D., Maternal and Perinatal Center, Tokyo Women's Medical College, 8- 1 Kawadacho, Shinjuku-ku. Tokyo 212, Japan.
medical knowledge should be revised as medical capabilities progress [5,6]. In 1991, the viability limit of fetal gestational age in the Eugenic Protection Act in Japan was amended from 24 weeks to 22 weeks because of the increasing number of infants surviving after less than 24 weeks gestation [7, 81. This article summarizes the most recent statistics on extremely low birthweight (ELBW) infants and their effect on the recent amendment to the Eugenic Protection Act in Japan.
Subjects and Method At the end of January 1991, the Subcommittee for Neonatal Surveillance of the Committee of Newborn Infants, Japan Pediatric Society, conducted a study on the outcome of neonates born in 1990 by mailing questionnaires and by tele-
Survival of extremely low birthweight infants (35) 613 Table 1. Neonatal mortality rates of infants born in 1990 and cared for at 51 1 hospitals with the facility to take care of sick neonates Birthweight (9)
No. admitted
Early neonatal death
Neonatal death
< 499 500- 999 1000-1499 1500- I999 2000-2499 2500
29
317 (43%) 15/16 (94%) 17/20 (85%) 21/25 (84%) 18/20 (90%) 20121 (95%) 11/12 (92%) 9/ 15 (60%)
of ELBW infants, and emphasizes the importance of ethical policy based on up-to-date medical achievements. The term ‘viability’does not simply mean ‘the ability to be born alive’ but does mean ‘the capability to grow and to develop normally in extrauterine environments’ [2, 81. Therefore, the discussion on viability should include the ultimate outcome of these ELBW infants from the viewpoints of physical and neurological growth and development. The incidence of major neurological sequelae, including cerebral palsy and mental retardation (IQ < 60), among 529 infants with birthweights less than 1,000g who were cared at 16 NICU in Tokyo between 1986 and 1988 and who were followed for more than 1 year was 18.0% (Table 6). When we further analyzed the follow-up data of very low birthweight infants cared for at Tokyo Women’s Medical College, only 8.8%of appropriate-for-date ELBW infants had major neurological sequelae, while 3 1.6% of light-for-date ELBW infants were handicapped (Table 7). These data allow us to speculate that
Vol. 34 No. 6 December 1992
Table 6. Incidence of neurological sequelae in infants < 1,000g in Tokyo 1986-88 Normal 428 (81%) Neurological sequelae 80 (15%) CP 30 (5.6%) MR 25 (4.7%) CP + MR 25 (4.7%) Borderline 21 (4%) Total 529 CP, cerebral palsy, MR, mental retardation.
even in these ELBW infants, prematurity per se plays a minor role in the occurrence of major sequelae, but most of their causes originated antenatally or perinatally. While there is a viability limit for ELBW infants, once they survive they should have the potential to grow and develop normally. If premature infants suffered from major sequelae, it was not because they were forced to live by modern technology in spite of their fatal destiny but because the antenatal, perinatal and postnatal management of them was inappropriate.
616 (38) Nishida and Ishizuka Table 7. Neurological Sequelae in Very Low Birthweight Infants (Tokyo Women’s Medical college 1984-89) Birthweight (9)
Light-for-date
Appropriate-for-date
Total
< 1000 1000-1499 Total
6/19 (31.6%) 4/26 (1 5.4%)
5/57 (8.8%) 2/59 (3.4%)
11/76 (14.5%) 6/85 (7.1%)
10/45 (22.2%)
7/116 (6.0%)
17/161 (10.6%)
Patients are followed for more than 1 year after estimated date of confinement.
Acknowledgements We thank members of the Committee of Newborn Infants (Chairman Dr Itsuro Yamanouchi), the Japan Neonatologist Association (President Dr Takeshi Hashimoto) and the doctors who participated in the survey for their support and co-operation.
References 1.
Reich WR. Introduction. In Reich WR ed: Encyclopedia of Bioethics. Free Press, New York. 1978, 1.
Dunn, PM. Age of fetal viability. Maternal Child Health 1985; 10: 102-104. 3. Editorial: Perinatal mortality rate-Time for a change?Lancet 1991; 337: 331-333. 4. Nishida H. Future ethical issues in neonatology: A Japanese perspective. Semin Perinatol 1987;-11:
6. 7.
8.
9.
2.
275-280. 5 . Nishida H. The viability of small premature
10.
infants and its effect on ethical decision making. Asian Med J 1989; 32: 562-567. Nishida H, Sakanoue M, Ishizuka Y. ‘How small is too small?’ in Japan 1983. Acta Paediatr Jpn 1986; 28: 195-201. Committee of Newborn Infant, Japan Society of Pediatrics. Report on the current status of NICU and neonatal mortality in Japan. J Jpn Pediatr Soc 1991; 95: 2454-2461 (in Jpn). Nishida H. The viability limit of gestation for the fetus and premature neonates. (The effect of recent amendment of Eugenic Protection Act in Japan). Asian Med J 1991; 35: 487-494. Ishizuka Y . Current conditions of NICU and mortality rate of very premature infants in Japan (Results of nationwide survey in January 1989). J Jpn Pediatr SOC1989 94: 84 1-847. Tada H. The annual report of the research on mental and physical disabilities by the Ministry of Health and Welfare. Study on improvement and evaluation of perinatal medical care system. 1989; H. Tada (ed.), Ministry of Health and Welfare, Tokyo, p 51-55.
Acta Paediatr Jpn
