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253 Cesarean section: Ranking risk factors for the Mexican American
316
spa Abstracts
Januar) 1991 Am J Ob,tet Gynecol
254 252 LONG-TERM EFFECTS OF INSTRUMENTAL DELIVERIES: A POPULATION BASED STUDY. D.S. Seidman x1 , R. Gale x2 , Y.L. Danon x3 ,4, A. Laor x3 , B. Chayen1 , D.K. Stevenson x5 . IDep. Obstet. Gynecol., Sheba Med. Center, Tel-Hashomer; 2Dep. Neonatol. Bikur Cholim Hosn., Jerusalem; 3IOF Med. Corps; 4Div. Pediatr. Immunol., Belinson Med. Cen. Israel; 50ep . Pediatr., Stanford, CA. To determine the long-term outcome of instrumental deliveries, 52,282 infants born in Jerusalem between Jan. 1964 and Dec. 1971 were followed-up for 17 years by matching computerized database records. The morbidity and intelliqence performance at 17-years of age associated with vacuum (n=1747) and forceps (n=937) extraction were compared with both soontaneous deliveries (n=47,500) and cesarean sections (n= 2098). A stepwise multiple reqression analvsis was used to estimate the influence of obstetrical interventions on intelligence test scores adjustinq for the effect of sex, birth weight, ethnic origin, paternal education, social class maternal age and birth order. The adjusted intelliqence scores were not siqnificantly different for subjects born by vacuum or forceps deliveries. Our findings sugqest that infants delivered by vacuum and forceos are not at risk for physical and conqnitive impairment at 17years of aqe.
253
CESAREAN SECTION: RANKING RISK FACTORS FOR THE MEXICAN AMERICAN. Oded Langer, Robert Huff, MIChael Berkus,' Department of OB/GYN, The University of Texas Health Science Center at San Antonio, TX There has been a substantial increase in the cesarean section (CS) rate over the past 15 years which is in part due to the continuous change in the indications for CIS. The purpose of this study was to measure the relative risk and influence of each factor for CIS on the decision-making process. 89,342 consecutive women delivering during 1970-85 were evaluated. Multivanate stepwise logistIC regression was used to determine the risk factors (30 potentially contributing dependent variables) and the I r effects on the odds ratio for CIS (dependent variable). The results revealed: 1) the primary indications for CIS were breech presentation (RR 58.45) and placenta previa (RR 18 42); 2) controlling for these 2 classic Indicators, only 8 factors were identified as significantly affecting the odds ratio for CIS: diabetes (2.64), prevIous CIS xl (036), CIS x2 (15.44), maternal age < 20 (2.79), maternal age> 35 (11.81), postdate (1.57), severe preeclampsia (2.46), abruptio placenta (1 84), fetal distress (3.28), and primigravida (3 00); 3) indications for CIS have remained constant during the 15-year period; and 4) Cox's multivariate survival model was used to predict the probability of CIS at various points of time during labor. The results are summarized:
Variable
Odds Ratio
Fetal wt > 4 4kg 1.66 Placenta previa 1 56 Bre&h 535 CIS x2 923 This study disclosed the risk factors and their net contnbution to the overall CIS rate upon labor floor admission. Furthermore, the survival model demonstrates that length of labor enhances the likelihood for vaginal delivery.
255
DOES MULTIPARITY IMPACT UPON FETAL WEIGHT? Oded Dept I YN, The Unlv of Texas Hlth Sci Ctr at San Antonio, TX The influence of parity on fetal weight is not well established Most studies have been based upon cross-sectional pooled data and not on a panel longitudinal design Our research question sought to examine the effect of multiparity on fetal weight 12,392 women with one or more subsequent deliveries (total 27,028) were evaluated longitudinally with each woman serving as her own control. The overall mean fetal weight by birth order (calculated from the total number of deliveries) served as a prime unit for analysis (shown ): !1Bn~er, xMichael 8erkus, Robert Huff, Louis Rld~way.
=
BIRTH FETAL WEIGHT
"OO~l ~ 3450
1 2 3 B,hH.OaOER 6 7 8 One-way analYSIS of vanance revealed Significantly lower fetal weight in first born vs. gravidas 1-8, para 2 vs parity 3-8, and para 3 vs. parity 4-8; no signifICant difference in fetal weight was disclosed from para 4 and higher. Additionally: 1) relative rISk for macrosomia is greater (RR 24,95%, Cl2.2-2 6) when high parity IS compared to first born; a higher risk (RR 1.3, 95%, CI 1.2-1.4) for low birth wei!Jht (LBW) was found only in first born compared to subsequent births; 2) linear relation exists between the rate of macrosomia (>4000g) and panty ranging from 45% (para 1) to 15% (para 8), P<.OOOI; in contrast, no relation exists between LBW «2500g) and parity with an overall rate of 8.2%; and 3) controlling for the effect of gestational age comparISon by birth percentile showed an association between LGA (> 90th percentile) and parity, with no relationship for SGA and panty We conclude that multiparity effects fetal weight In the first 3 pregnancies and IS also a risk factor for macrosomia In contrast, grand multiparity is not a risk factor for low-birth-weight infants.
PERINATAL MORTALITY: RANKING OBSTETRICAL RISK FACTORS IN 89.342 BIRTHS. Oded LanQjer, Robert Huff, 'Michael Berkus, 'Elly Xenakls Dept OB/GYN, nlV TX HSC at San AntOniO, TX. Research priorities have focused attention on the rates and causes of perinatal mortality but have failed to provide an estimate of the net effect of each factor This study identified and ranked risk factors contributing to pennatal mortality with the use of the logistic regression model. The resulting odds ratios indicate the net effect of a given factor when all other independent variables are controlled All consecutive deliveries (89,342) during the 1970-85 period were included. Perinatal mortality was defined as stillbirth > 20 weeks (wks)gestatlOn or deaths occurring dunng the first 28 postnatal days Results revealed: 1) of the 33 variables examined, only 9 were identified as significantly affecting the odds ratio for pennatal mortality: fetal weight <2500g (931), shoulder dystOCia (868), gestational age 26-29 wks (2279), 30-33 wks (386) and 2:42 wks (205), breech presentation (275), placenta previa (5.73). diabetes (3.54). preeclampsia (1 71), primagravida (1.61), maternal age < 20 (1.36) and 2:35 (431); and 2) the odds ratio of the different components of perinatal mortality are shown in the table below: Variable Stillbirth NO Day 1 NO Day 2-7 NO Day 8-28 GA 26-29wk NS 301 4.20 10.69 GA 30-33 wk NS NS NS 5.21 GA 34-37 wk NS NS NS 2 25 GA 2:42 wk 289 NS NS NS Age < 20 hr 1.75 NS NS NS Age 2:35 hr 620 NS NS NS Weight <2500g 396 828 500 NS Weight >4000g 2.19 NS NS NS Diabetes 2 54 NS NS NS Hypertension 3.79 NS NS NS Shoulder dys 11 53 7 07 NS NS Previous SB x2 267 NS 282 NS Breech NS 246 NS NS In conclusion, recognition of the magnitude of each factor and the time period in which it can cause irreverSible adverse outcome may further reduce perinatal mortality rates.
spa Abstracts
Januar) 1991 Am J Ob,tet Gynecol
254 252 LONG-TERM EFFECTS OF INSTRUMENTAL DELIVERIES: A POPULATION BASED STUDY. D.S. Seidman x1 , R. Gale x2 , Y.L. Danon x3 ,4, A. Laor x3 , B. Chayen1 , D.K. Stevenson x5 . IDep. Obstet. Gynecol., Sheba Med. Center, Tel-Hashomer; 2Dep. Neonatol. Bikur Cholim Hosn., Jerusalem; 3IOF Med. Corps; 4Div. Pediatr. Immunol., Belinson Med. Cen. Israel; 50ep . Pediatr., Stanford, CA. To determine the long-term outcome of instrumental deliveries, 52,282 infants born in Jerusalem between Jan. 1964 and Dec. 1971 were followed-up for 17 years by matching computerized database records. The morbidity and intelliqence performance at 17-years of age associated with vacuum (n=1747) and forceps (n=937) extraction were compared with both soontaneous deliveries (n=47,500) and cesarean sections (n= 2098). A stepwise multiple reqression analvsis was used to estimate the influence of obstetrical interventions on intelligence test scores adjustinq for the effect of sex, birth weight, ethnic origin, paternal education, social class maternal age and birth order. The adjusted intelliqence scores were not siqnificantly different for subjects born by vacuum or forceps deliveries. Our findings sugqest that infants delivered by vacuum and forceos are not at risk for physical and conqnitive impairment at 17years of aqe.
253
CESAREAN SECTION: RANKING RISK FACTORS FOR THE MEXICAN AMERICAN. Oded Langer, Robert Huff, MIChael Berkus,' Department of OB/GYN, The University of Texas Health Science Center at San Antonio, TX There has been a substantial increase in the cesarean section (CS) rate over the past 15 years which is in part due to the continuous change in the indications for CIS. The purpose of this study was to measure the relative risk and influence of each factor for CIS on the decision-making process. 89,342 consecutive women delivering during 1970-85 were evaluated. Multivanate stepwise logistIC regression was used to determine the risk factors (30 potentially contributing dependent variables) and the I r effects on the odds ratio for CIS (dependent variable). The results revealed: 1) the primary indications for CIS were breech presentation (RR 58.45) and placenta previa (RR 18 42); 2) controlling for these 2 classic Indicators, only 8 factors were identified as significantly affecting the odds ratio for CIS: diabetes (2.64), prevIous CIS xl (036), CIS x2 (15.44), maternal age < 20 (2.79), maternal age> 35 (11.81), postdate (1.57), severe preeclampsia (2.46), abruptio placenta (1 84), fetal distress (3.28), and primigravida (3 00); 3) indications for CIS have remained constant during the 15-year period; and 4) Cox's multivariate survival model was used to predict the probability of CIS at various points of time during labor. The results are summarized:
Variable
Odds Ratio
Fetal wt > 4 4kg 1.66 Placenta previa 1 56 Bre&h 535 CIS x2 923 This study disclosed the risk factors and their net contnbution to the overall CIS rate upon labor floor admission. Furthermore, the survival model demonstrates that length of labor enhances the likelihood for vaginal delivery.
255
DOES MULTIPARITY IMPACT UPON FETAL WEIGHT? Oded Dept I YN, The Unlv of Texas Hlth Sci Ctr at San Antonio, TX The influence of parity on fetal weight is not well established Most studies have been based upon cross-sectional pooled data and not on a panel longitudinal design Our research question sought to examine the effect of multiparity on fetal weight 12,392 women with one or more subsequent deliveries (total 27,028) were evaluated longitudinally with each woman serving as her own control. The overall mean fetal weight by birth order (calculated from the total number of deliveries) served as a prime unit for analysis (shown ): !1Bn~er, xMichael 8erkus, Robert Huff, Louis Rld~way.
=
BIRTH FETAL WEIGHT
"OO~l ~ 3450
1 2 3 B,hH.OaOER 6 7 8 One-way analYSIS of vanance revealed Significantly lower fetal weight in first born vs. gravidas 1-8, para 2 vs parity 3-8, and para 3 vs. parity 4-8; no signifICant difference in fetal weight was disclosed from para 4 and higher. Additionally: 1) relative rISk for macrosomia is greater (RR 24,95%, Cl2.2-2 6) when high parity IS compared to first born; a higher risk (RR 1.3, 95%, CI 1.2-1.4) for low birth wei!Jht (LBW) was found only in first born compared to subsequent births; 2) linear relation exists between the rate of macrosomia (>4000g) and panty ranging from 45% (para 1) to 15% (para 8), P<.OOOI; in contrast, no relation exists between LBW «2500g) and parity with an overall rate of 8.2%; and 3) controlling for the effect of gestational age comparISon by birth percentile showed an association between LGA (> 90th percentile) and parity, with no relationship for SGA and panty We conclude that multiparity effects fetal weight In the first 3 pregnancies and IS also a risk factor for macrosomia In contrast, grand multiparity is not a risk factor for low-birth-weight infants.
PERINATAL MORTALITY: RANKING OBSTETRICAL RISK FACTORS IN 89.342 BIRTHS. Oded LanQjer, Robert Huff, 'Michael Berkus, 'Elly Xenakls Dept OB/GYN, nlV TX HSC at San AntOniO, TX. Research priorities have focused attention on the rates and causes of perinatal mortality but have failed to provide an estimate of the net effect of each factor This study identified and ranked risk factors contributing to pennatal mortality with the use of the logistic regression model. The resulting odds ratios indicate the net effect of a given factor when all other independent variables are controlled All consecutive deliveries (89,342) during the 1970-85 period were included. Perinatal mortality was defined as stillbirth > 20 weeks (wks)gestatlOn or deaths occurring dunng the first 28 postnatal days Results revealed: 1) of the 33 variables examined, only 9 were identified as significantly affecting the odds ratio for pennatal mortality: fetal weight <2500g (931), shoulder dystOCia (868), gestational age 26-29 wks (2279), 30-33 wks (386) and 2:42 wks (205), breech presentation (275), placenta previa (5.73). diabetes (3.54). preeclampsia (1 71), primagravida (1.61), maternal age < 20 (1.36) and 2:35 (431); and 2) the odds ratio of the different components of perinatal mortality are shown in the table below: Variable Stillbirth NO Day 1 NO Day 2-7 NO Day 8-28 GA 26-29wk NS 301 4.20 10.69 GA 30-33 wk NS NS NS 5.21 GA 34-37 wk NS NS NS 2 25 GA 2:42 wk 289 NS NS NS Age < 20 hr 1.75 NS NS NS Age 2:35 hr 620 NS NS NS Weight <2500g 396 828 500 NS Weight >4000g 2.19 NS NS NS Diabetes 2 54 NS NS NS Hypertension 3.79 NS NS NS Shoulder dys 11 53 7 07 NS NS Previous SB x2 267 NS 282 NS Breech NS 246 NS NS In conclusion, recognition of the magnitude of each factor and the time period in which it can cause irreverSible adverse outcome may further reduce perinatal mortality rates.