title: Strength of association between umbilical cord pH and perinatal and long term outcomes: systematic review and meta-analysis.
abstract: OBJECTIVE
  To evaluate the association between umbilical cord pH at birth and long term outcomes.
  
  
  METHODS
  Systematic review and meta-analysis.
  
  
  METHODS
  Medline (1966-August 2008), Embase (1980-August 2008), the Cochrane Library (2008 issue 8), and Medion, without language restrictions; reference lists of selected articles; and contact with authors.
  
  
  METHODS
  Studies in which cord pH at birth was compared with any neonatal or long term outcome. Cohort and case-control designs were included.
  
  
  RESULTS
  51 articles totalling 481 753 infants met the selection criteria. Studies varied in design, quality, outcome definition, and results. Meta-analysis carried out within predefined groups showed that low arterial cord pH was significantly associated with neonatal mortality (odds ratio 16.9, 95% confidence interval 9.7 to 29.5, I(2)=0%), hypoxic ischaemic encephalopathy (13.8, 6.6 to 28.9, I(2)=0%), intraventricular haemorrhage or periventricular leucomalacia (2.9, 2.1 to 4.1, I(2)=0%), and cerebral palsy (2.3, 1.3 to 4.2, I(2)=0%).
  
  
  CONCLUSIONS
  Low arterial cord pH showed strong, consistent, and temporal associations with clinically important neonatal outcomes that are biologically plausible. These data can be used to inform clinical management and justify the use of arterial cord pH as an important outcome measure alongside neonatal morbidity and mortality in obstetric trials.
authors.affiliation: Department of Obstetrics, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham. g.l.malin@bham.ac.uk
authors.forename: Gemma L
authors.initials: GL
authors.lastname: Malin
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Morris
authors.forename: Khalid S
authors.initials: KS
authors.lastname: Khan
mesh_terms: D000138:Acidosis / Q000097:blood* / Q000401:mortality; D002547:Cerebral Palsy / Q000097:blood / Q000401:mortality; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007226:Infant Mortality; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000097:blood* / Q000401:mortality; D011379:Prognosis; D012307:Risk Factors
references.citation: Lyon Med. 1972 Apr 23;227(8):699-702
references.pmid: 5065507
references.citation: Z Geburtshilfe Perinatol. 1974 Feb;178(1):23-9
references.pmid: 4829692
references.citation: BMJ. 2001 Jul 7;323(7303):42-6
references.pmid: 11440947
references.citation: Z Geburtshilfe Neonatol. 2003 May-Jun;207(3):84-9
references.pmid: 12891466
references.citation: Arch Dis Child. 1983 Jan;58(1):15-9
references.pmid: 6830269
references.citation: BMJ. 2000 Apr 15;320(7241):1075-6
references.pmid: 10764378
references.citation: Am J Obstet Gynecol. 1996 May;174(5):1433-40
references.pmid: 9065108
references.citation: Int J Epidemiol. 1997 Dec;26(6):1137-41
references.pmid: 9447391
references.citation: J Matern Fetal Med. 2001 Aug;10(4):264-8
references.pmid: 11531153
references.citation: Obstet Gynecol. 1989 Apr;73(4):597-600
references.pmid: 2927855
references.citation: J Perinat Med. 2008;36(2):151-6
references.pmid: 18211252
references.citation: Resuscitation. 1999 Sep;42(1):11-7
references.pmid: 10524727
references.citation: BMC Med Res Methodol. 2006 Jul 12;6:31
references.pmid: 16836745
references.citation: Stat Med. 2002 Jun 15;21(11):1525-37
references.pmid: 12111918
references.citation: J Clin Epidemiol. 2009 Dec;62(12):1292-300
references.pmid: 19447007
references.citation: Am J Obstet Gynecol. 1996 Nov;175(5):1152-7
references.pmid: 8942481
references.citation: Obstet Gynecol. 1991 Dec;78(6):1103-7
references.pmid: 1945216
references.citation: Br J Obstet Gynaecol. 1986 Mar;93(3):217-22
references.pmid: 3964596
references.citation: BMJ. 2001 Jul 21;323(7305):157-62
references.pmid: 11463691
references.citation: Br J Obstet Gynaecol. 1997 Oct;104(10):1123-7
references.pmid: 9332988
references.citation: Proc R Soc Med. 1965 May;58:295-300
references.pmid: 14283879
references.citation: J R Soc Med. 2001 Dec;94(12):624-7
references.pmid: 11733588
references.citation: Am J Obstet Gynecol. 2001 Jun;184(7):1422-5; discussion 1425-6
references.pmid: 11408862
references.citation: Obstet Gynecol. 1991 Nov;78(5 Pt 1):768-73
references.pmid: 1923194
references.citation: J Matern Fetal Neonatal Med. 2002 Aug;12(2):123-6
references.pmid: 12420843
references.citation: Am J Obstet Gynecol. 2002 Jul;187(1):1-9
references.pmid: 12114881
references.citation: Lancet. 1995 Dec 2;346(8988):1449-54
references.pmid: 7490990
references.citation: Am J Obstet Gynecol. 1987 Sep;157(3):676-9
references.pmid: 3631168
references.citation: Arch Gynecol Obstet. 1993;253(2):103-15
references.pmid: 8215607
references.citation: Am J Obstet Gynecol. 1993 Jul;169(1):61-70
references.pmid: 8333477
references.citation: Int J Gynaecol Obstet. 2003 Jun;81(3):267-71
references.pmid: 12767568
references.citation: BMJ. 2004 Feb 7;328(7435):314
references.pmid: 14744822
references.citation: Am J Obstet Gynecol. 1999 Apr;180(4):1024-9
references.pmid: 10203673
references.citation: Zhonghua Fu Chan Ke Za Zhi. 1998 Aug;33(8):462-5
references.pmid: 10806742
references.citation: Pediatr Res. 2001 Jun;49(6):735-41
references.pmid: 11385130
references.citation: Ment Retard Dev Disabil Res Rev. 2001;7(1):56-64
references.pmid: 11241883
references.citation: Br J Obstet Gynaecol. 1994 Sep;101(9):774-81
references.pmid: 7524647
references.citation: Am J Obstet Gynecol. 1989 Sep;161(3):825-30
references.pmid: 2782367
references.citation: JAMA. 1994 Mar 2;271(9):703-7
references.pmid: 8309035
references.citation: Biol Neonate. 1995;67(1):39-46
references.pmid: 7748974
references.citation: Am J Obstet Gynecol. 1989 Jul;161(1):213-20
references.pmid: 2750807
references.citation: Stat Med. 2006 Oct 30;25(20):3443-57
references.pmid: 16345038
references.citation: JAMA. 2003 May 21;289(19):2554-9
references.pmid: 12759327
references.citation: Am J Obstet Gynecol. 2000 May;182(5):1210-4
references.pmid: 10819860
references.citation: Am J Obstet Gynecol. 1991 Feb;164(2):637-41
references.pmid: 1992716
references.citation: J Clin Epidemiol. 2005 Oct;58(10):982-90
references.pmid: 16168343
references.citation: Obstet Gynecol. 2002 Sep;100(3):557-60
references.pmid: 12220778
references.citation: Eur J Obstet Gynecol Reprod Biol. 2003 Jun 10;108(2):121-5
references.pmid: 12781397
references.citation: Int J Epidemiol. 2000 Jun;29(3):387-90
references.pmid: 10869307
references.citation: J Pediatr (Rio J). 2007 Mar-Apr;83(2):186-90
references.pmid: 17380228
references.citation: Am J Obstet Gynecol. 2007 Sep;197(3):301.e1-8
references.pmid: 17826429
references.citation: Int J Dev Neurosci. 2008 Feb;26(1):93-101
references.pmid: 17936538
references.citation: Eur J Obstet Gynecol Reprod Biol. 2007 Feb;130(2):169-75
references.pmid: 16621222
references.citation: Early Hum Dev. 2008 Jan;84(1):37-41
references.pmid: 17379460
references.citation: Am J Obstet Gynecol. 1994 Jan;170(1 Pt 1):48-53
references.pmid: 8296844
references.citation: Singapore Med J. 1998 Apr;39(4):151-5
references.pmid: 9676144
references.citation: J Midwifery Womens Health. 2005 Nov-Dec;50(6):498-506
references.pmid: 16260364
references.citation: Am J Obstet Gynecol. 2004 Oct;191(4):1305-10
references.pmid: 15507958
references.citation: J R Stat Soc Ser A Stat Soc. 2009 Jan;172(1):137-159
references.pmid: 19381330
references.citation: J Perinat Med. 1989;17(2):99-106
references.pmid: 2681671
references.citation: Early Hum Dev. 2005 Jun;81(6):535-44
references.pmid: 15935931
references.citation: Arch Dis Child Fetal Neonatal Ed. 1994 Sep;71(2):F93-6
references.pmid: 7979485
references.citation: Obstet Gynecol Clin North Am. 1999 Dec;26(4):695-709
references.pmid: 10587963
references.citation: BMJ. 1999 Oct 16;319(7216):1054-9
references.pmid: 10521205
references.citation: Obstet Gynecol. 2002 Jan;99(1):29-34
references.pmid: 11777506
references.citation: J Perinat Med. 1996;24(6):677-86
references.pmid: 9120752
references.citation: JAMA. 2000 Apr 19;283(15):2008-12
references.pmid: 10789670
references.citation: Am J Obstet Gynecol. 1992 Dec;167(6):1506-12
references.pmid: 1471655
references.citation: BMJ. 2003 Jan 4;326(7379):41-4
references.pmid: 12511463
references.citation: Am J Obstet Gynecol. 1997 Dec;177(6):1391-4
references.pmid: 9423740
references.citation: Am J Obstet Gynecol. 2001 Feb;184(3):447-50
references.pmid: 11228501
references.citation: Early Hum Dev. 1979 Jul;3(2):155-61
references.pmid: 43802
references.citation: Clin Exp Obstet Gynecol. 1995;22(3):235-9
references.pmid: 7554263
references.citation: Early Hum Dev. 1979 Jul;3(2):141-54
references.pmid: 535545
references.citation: Eur J Obstet Gynecol Reprod Biol. 2006 Jul;127(1):29-34
references.pmid: 16815469
references.citation: BMJ. 2009 Dec 30;339:b4184
references.pmid: 20042483
references.citation: Early Hum Dev. 1985 May;11(1):33-42
references.pmid: 4006823
references.citation: BMC Med Res Methodol. 2003 Nov 10;3:25
references.pmid: 14606960
references.citation: Rev Neurol. 2000 Jul 16-31;31(2):107-13
references.pmid: 10951663
references.citation: Am J Epidemiol. 1998 Mar 1;147(5):415-25
references.pmid: 9525527
references.citation: Int J Obstet Anesth. 1995 Apr;4(2):78-81
references.pmid: 15636982
references.citation: Am J Obstet Gynecol. 2004 Sep;191(3):864-71
references.pmid: 15467555
references.citation: Pediatrics. 1996 Apr;97(4):456-62
references.pmid: 8632928
references.citation: BMC Med Res Methodol. 2005 May 26;5:19
references.pmid: 15918898
references.citation: Obstet Gynecol. 1993 Jun;81(6):899-907
references.pmid: 8497353
references.citation: BMJ. 2001 Jul 14;323(7304):101-5
references.pmid: 11451790
references.citation: Z Kinder Jugendpsychiatr. 1985;13(1):24-30
references.pmid: 3837556
references.citation: Eur J Obstet Gynecol Reprod Biol. 2001 Mar;95(1):6-11
references.pmid: 11267714
references.citation: N Engl J Med. 2004 Nov 4;351(19):1985-95
references.pmid: 15525724
references.citation: Am J Perinatol. 1995 Nov;12(6):429-36
references.pmid: 8579656
references.citation: Am J Obstet Gynecol. 1994 Apr;170(4):991-8; discussion 998-9
references.pmid: 8166220
references.citation: Am J Epidemiol. 1987 May;125(5):761-8
references.pmid: 3551588
references.citation: Biol Neonate. 1999;75(1):9-17
references.pmid: 9831679
references.citation: BMJ. 2003 Sep 6;327(7414):557-60
references.pmid: 12958120