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532 The Relationship of “Complete” Cord Arterial Blood Gases to Gestational Age and Neonatal Outcome
420
532
SPO Abstracts
January 1992 Am J Obstet Gynecol
THE RELATIONSHIP OF -COMPLETE- CORD ARTERIAL BLOOD GASES TO GESTATIONAL AGE AND NEONATAL OUTCOME.A. Hiettl.. L.Devoe A.Youssef,XDept.OBGYN,Med.CoI.Georgia,Augusta,GA We reviewed umbilical artery blood gases(UABGs) in 3000 consecutive deliveries, 32 - 42 weeks' gestation,to determine rates of neonatal metabolic (MET),mixed(MIX),and respiratory (RESP) acidoses, (by criteria of Gilstrap, Obstet Gynecol 1987;70: 191 ), and gestational-age related rates of infant morbidity !lQ!. due to sequelae of respiratory distress or major anomalies. Acidosis types and rates were similar for term(T) and preterm(PT) groups (v. table, numbers in ( ) = morbidity). GA(wks) Total MID:. ~ MIX 32-36 37-42
261 2315
3(1) 16(7)
534
Recent reports OD hlKber order multiple births (triplets ... ltigher) cared for in tertiary centers SIIIIIIest that Ibeir survival bas improved dramaticaUy (e.II., Goaen et al. Am J Obstet Gynecoll990; 162: 4.54-9). But bospitalbased studies may not be aeneralizableto Ibe entire birth population. We Ibereforeanalyzed birthweiaht-specificinfant mortality rates (lMRs) BIDOOII sinaJetODS, twins, and hlKber order multiple births in Ibe U.S. in 1983-5 and compared Ibe latter rates to Ibose in 1960. 1u whites in 1983-5, Ibe relative risk (RR) of infant mortality &mOBIl bigher order multiple births compared to sinaJetODS was 15.9 (130.3 vs. 8.2 per 1000 live births). 10 blacks, Ibe RR was 13.2 (224.5 vs. 17.0). This was due aboost entirely to Ibe lower weiaht distribution of bigher order multiple births. 10 whites, 89% weiahed < 2500g, as compared to 4.8% of sinKletODS. 10 blacks, 92 % weiabed <2500g, as compared to 11.4% of sinilIetODS. Higher order multiple birtbs who weighed 500-999g bad about Ibe same IMR as singletODS. 10 weight categories 1000-24991, Ibe IMR in hlKber order multiple birtbs was much lower: weiaht-specific RRs ranaed from 0.30 to 0.73. Between 1960 and 1983-5, in bigh order multiple births Ibe IMR decJined 49% in VLBW white infants (from 683 to 351), 55% in VLBW black infants (from 941 to 423), 80% in whites weiabin111500-2499g (from 75 to 15), and 73% in blacks weiabinII 1500-24991 (from 129 to 35). Similar patterns were found in analyses of perinatal mortality. Thus, modera intensive care tecbniques bave bad a similar beneficial impact on Ibe survival of sinKletons, twins; and hlKber order multiple births.
17(6) 161(26)
20(9) 233(38) significantly lower for all T (3 %)
Morbidity was than PT (6%) acidosis groups. While morbidity rates rose as pH fell (7.20 -> 6.75), 50% of morbid cases in both groups occurred at pH >7.15 and < 7.20. Morbidity in the PT group was similarly distributed in all acidosis types (X2-A2,NS); in the T group, it was significantly higher with MET (p=.02). These data suggest that UA pH alone may be adequate for preterm infants as !l!Y. acidosis appears equally harmful. Term gestations require complete UABGs to discriminate risk of morbidity.
533
INTRAtrrERINE GROWfH RETARDATION: 1M U.S. DATA COMPARED TO PREVIOUS STANDARDS M. Kiely,' J.L. Kiely,' Materaal and Cbild Health Bureau, Heallb Resources and Services AdmiDistratiOD, Rockville, MD, and NCBS. 17 yean l1li0 Hoffman et al. published birth weiaht lor aestatioo percentiles based OD a 58% sample 01 aU US live births born in 1968 (Qbstet Gmf(;ol ~ 1974;29:651-81). The JIUI1I08I! 01 our analysis was to explore whetber distributiODS of birth weiaht lor lIestatiOD in Ibe US shifted upward between 1968 and 1M. We used US live birth files from Ibe National Center lor Health Statistics. For each year from 1968 to 1M, we calculated Ibe median birth weiaht and Ibe lOtb percentile for lIestatiODS between 28 and 45 weeks. This was dODe separately lor 8 Kr0UPS by race (blacks, whites), parity (primiparae, multiparae) and sex. 1u aU 8 race/parity/sex subKr0ups Ibere were substantial upward shifts in birth weiabt at lIestationalllles 0136 weeks and more. The lOtb percentile increased 80-190 Krams. The table below shows Ibese upward shifts for selected lIestationalllles BIDOOII males. These data provide further evidence for Ibe recommendatiOD of GoldenberK et al.
lNFANT MORTALITY iN mGHER ORDER MULTIPLE BlRTIlS, UNITED STATES 1960 AND 1983-1985. ~,' M. Kiely,' J.C. KJeimnan,' National Center for Healtb Statistics, Hyattsville, MD and Materaal and Cbild Health Bureau, URSA.
• See KJeimnan et al.(Am J EpidemioI1991; 133: 133-43) for a detailed analysis of U.S. time trends in infant mortality in twins and singletODS.
535
MENSTRUAL DATING-NOW AN INADEOUATE ESTIMATOR OF GESTATIONAL AGE MP Dombrowski. HM Wolfe, YW Brans: AA Saleh, RJ Sokol, Depts of Ob/Gyn and Pediatrics, Wayne State Univ.lHutzel Hosp., Detroit, MI Although current practice is to use fetal ultrasound and Ballard for gestational age (GA) dating, birth weight percentiles (BW '!btiles) are still based solely on GA by last menstrual periods (GA-LMP). The purpose of this study was to develop a standard consistent with current technology and practice. ObstetriC estimates of GA (GA-OB) were based on LMPs but corrected by ultrasounds and confirmed by Ballard exams. From a perinatal database, weights were obtained for 33,135 viable, singleton, structurally normal neonates. Depicted are the 10th, 50th and 90th '!btiles, based on GA-OB (bold lines) and GA-LMP (light lines). Data shown if n > 20/week. 4
4500
4lXXl 3500 300J
2500 2000
Tenlb percentile birth weiabt values at various gestational ages
I
36
I
38
I
40
I
1500
42
Wbites: 1968
2259
2621
2890
3010
1M
2426
2807
3050
3090
+167
+186
+160
+80
Difference Blacks: 1968
2227
2544
26"
2660
1988
2325
2665
2835
2835
+98
+121
+159
+175
Difference
1000 500 20
25
30
35
40
45
srP
Consistent with previously published BW '!btiles for neonates preterm by GA-LMP, data are widely divergent with a decrease in median BW '!btiles beyond 42 weeks when compared to BW '!btiles by GA-OB. We conclude: 1) use of ultrasound increases the precision of GA dating, 2) BW '!btiles based solely on LMP are likely to be inaccurate for preterm and post-term gestations, 3) since fetal growth typically continues to 44 weeks, macrosomia rather than growth retardation is the greater risk of post-datism.
532
SPO Abstracts
January 1992 Am J Obstet Gynecol
THE RELATIONSHIP OF -COMPLETE- CORD ARTERIAL BLOOD GASES TO GESTATIONAL AGE AND NEONATAL OUTCOME.A. Hiettl.. L.Devoe A.Youssef,XDept.OBGYN,Med.CoI.Georgia,Augusta,GA We reviewed umbilical artery blood gases(UABGs) in 3000 consecutive deliveries, 32 - 42 weeks' gestation,to determine rates of neonatal metabolic (MET),mixed(MIX),and respiratory (RESP) acidoses, (by criteria of Gilstrap, Obstet Gynecol 1987;70: 191 ), and gestational-age related rates of infant morbidity !lQ!. due to sequelae of respiratory distress or major anomalies. Acidosis types and rates were similar for term(T) and preterm(PT) groups (v. table, numbers in ( ) = morbidity). GA(wks) Total MID:. ~ MIX 32-36 37-42
261 2315
3(1) 16(7)
534
Recent reports OD hlKber order multiple births (triplets ... ltigher) cared for in tertiary centers SIIIIIIest that Ibeir survival bas improved dramaticaUy (e.II., Goaen et al. Am J Obstet Gynecoll990; 162: 4.54-9). But bospitalbased studies may not be aeneralizableto Ibe entire birth population. We Ibereforeanalyzed birthweiaht-specificinfant mortality rates (lMRs) BIDOOII sinaJetODS, twins, and hlKber order multiple births in Ibe U.S. in 1983-5 and compared Ibe latter rates to Ibose in 1960. 1u whites in 1983-5, Ibe relative risk (RR) of infant mortality &mOBIl bigher order multiple births compared to sinaJetODS was 15.9 (130.3 vs. 8.2 per 1000 live births). 10 blacks, Ibe RR was 13.2 (224.5 vs. 17.0). This was due aboost entirely to Ibe lower weiaht distribution of bigher order multiple births. 10 whites, 89% weiahed < 2500g, as compared to 4.8% of sinKletODS. 10 blacks, 92 % weiabed <2500g, as compared to 11.4% of sinilIetODS. Higher order multiple birtbs who weighed 500-999g bad about Ibe same IMR as singletODS. 10 weight categories 1000-24991, Ibe IMR in hlKber order multiple birtbs was much lower: weiaht-specific RRs ranaed from 0.30 to 0.73. Between 1960 and 1983-5, in bigh order multiple births Ibe IMR decJined 49% in VLBW white infants (from 683 to 351), 55% in VLBW black infants (from 941 to 423), 80% in whites weiabin111500-2499g (from 75 to 15), and 73% in blacks weiabinII 1500-24991 (from 129 to 35). Similar patterns were found in analyses of perinatal mortality. Thus, modera intensive care tecbniques bave bad a similar beneficial impact on Ibe survival of sinKletons, twins; and hlKber order multiple births.
17(6) 161(26)
20(9) 233(38) significantly lower for all T (3 %)
Morbidity was than PT (6%) acidosis groups. While morbidity rates rose as pH fell (7.20 -> 6.75), 50% of morbid cases in both groups occurred at pH >7.15 and < 7.20. Morbidity in the PT group was similarly distributed in all acidosis types (X2-A2,NS); in the T group, it was significantly higher with MET (p=.02). These data suggest that UA pH alone may be adequate for preterm infants as !l!Y. acidosis appears equally harmful. Term gestations require complete UABGs to discriminate risk of morbidity.
533
INTRAtrrERINE GROWfH RETARDATION: 1M U.S. DATA COMPARED TO PREVIOUS STANDARDS M. Kiely,' J.L. Kiely,' Materaal and Cbild Health Bureau, Heallb Resources and Services AdmiDistratiOD, Rockville, MD, and NCBS. 17 yean l1li0 Hoffman et al. published birth weiaht lor aestatioo percentiles based OD a 58% sample 01 aU US live births born in 1968 (Qbstet Gmf(;ol ~ 1974;29:651-81). The JIUI1I08I! 01 our analysis was to explore whetber distributiODS of birth weiaht lor lIestatiOD in Ibe US shifted upward between 1968 and 1M. We used US live birth files from Ibe National Center lor Health Statistics. For each year from 1968 to 1M, we calculated Ibe median birth weiaht and Ibe lOtb percentile for lIestatiODS between 28 and 45 weeks. This was dODe separately lor 8 Kr0UPS by race (blacks, whites), parity (primiparae, multiparae) and sex. 1u aU 8 race/parity/sex subKr0ups Ibere were substantial upward shifts in birth weiabt at lIestationalllles 0136 weeks and more. The lOtb percentile increased 80-190 Krams. The table below shows Ibese upward shifts for selected lIestationalllles BIDOOII males. These data provide further evidence for Ibe recommendatiOD of GoldenberK et al.
lNFANT MORTALITY iN mGHER ORDER MULTIPLE BlRTIlS, UNITED STATES 1960 AND 1983-1985. ~,' M. Kiely,' J.C. KJeimnan,' National Center for Healtb Statistics, Hyattsville, MD and Materaal and Cbild Health Bureau, URSA.
• See KJeimnan et al.(Am J EpidemioI1991; 133: 133-43) for a detailed analysis of U.S. time trends in infant mortality in twins and singletODS.
535
MENSTRUAL DATING-NOW AN INADEOUATE ESTIMATOR OF GESTATIONAL AGE MP Dombrowski. HM Wolfe, YW Brans: AA Saleh, RJ Sokol, Depts of Ob/Gyn and Pediatrics, Wayne State Univ.lHutzel Hosp., Detroit, MI Although current practice is to use fetal ultrasound and Ballard for gestational age (GA) dating, birth weight percentiles (BW '!btiles) are still based solely on GA by last menstrual periods (GA-LMP). The purpose of this study was to develop a standard consistent with current technology and practice. ObstetriC estimates of GA (GA-OB) were based on LMPs but corrected by ultrasounds and confirmed by Ballard exams. From a perinatal database, weights were obtained for 33,135 viable, singleton, structurally normal neonates. Depicted are the 10th, 50th and 90th '!btiles, based on GA-OB (bold lines) and GA-LMP (light lines). Data shown if n > 20/week. 4
4500
4lXXl 3500 300J
2500 2000
Tenlb percentile birth weiabt values at various gestational ages
I
36
I
38
I
40
I
1500
42
Wbites: 1968
2259
2621
2890
3010
1M
2426
2807
3050
3090
+167
+186
+160
+80
Difference Blacks: 1968
2227
2544
26"
2660
1988
2325
2665
2835
2835
+98
+121
+159
+175
Difference
1000 500 20
25
30
35
40
45
srP
Consistent with previously published BW '!btiles for neonates preterm by GA-LMP, data are widely divergent with a decrease in median BW '!btiles beyond 42 weeks when compared to BW '!btiles by GA-OB. We conclude: 1) use of ultrasound increases the precision of GA dating, 2) BW '!btiles based solely on LMP are likely to be inaccurate for preterm and post-term gestations, 3) since fetal growth typically continues to 44 weeks, macrosomia rather than growth retardation is the greater risk of post-datism.