S236

569

SMFM Abstracts

ANGIOTENSINOGEN (AGT) GENOTYPE AND I N S U L I N / G L U C O S E RATIO IRA BERNSTEIN 1, ADRIENNE SCHONBERG 1, KENNETH WARDS; tUniv, ofVT, OB/GYN, Burl., VT; 2Univ. ofUT, OB/GYN, Salt Lake City, UT

OBJECTIVE: The "Fetal Origins" hypothesis suggests that fetal growth restriction results in adult disease including hypertension and insulin resis- tance. The TT 235 polymorphism of AGT has been independently associated with preeclampsia, fetal growth restriction and adult hypertension. We sought to determine if the TT 235 AGT variant is associated with insulin resistance in young women reflected by elevated fSsting insulin/glucose ratios.

STUDY DESIGN: We studied 40 nulligravid healthy young women dur ing the follicular phase (day 10 _+ 2) of the menstrual cycle. None of the women were diabetic or hypertensive. Studies were pe r fo rmed in the pnstabsorptive state following an overnight fast. Plasma gluocose and insulin were measured by glucose oxidase and RIA respectively. AGT genotype was determined using mutagenically separated PCR. Analyses were per formed using ANOVA.

RESULTS: O f the 40 women studied, 13 car r ied the MM AGT polymorphism (33%), 22 were MT (55%) and 5 were TT (12%). There was no difference between groups with regard to age (MM 26.2 + 5.0, MT 25.4 -+ 5.1, TT 25.6 _+ 4.6 years P = .90 (mean + s.d.)), body mass index (MM 23.0 ± 2.3, MT 22.7 _+ 3.2, TT 22.8 + 44.5 k g / m 2 P= .97) or b lood glucose (MM 85.5 + 4.7, MT 84.9 + 5.9, TT 81.8 ± 10.8 m g / d l P= .52). Plasma insulin/glucose ratios (insulin (ulU/ml)/glucose (mg/dl) x 100) were similar across groups MM 2.35 (2.29- 2.58), MT 2.44 (2.23-2.70), TT 2.38 (2.25-2.58) (median (25-75th percentile), P = .57 ANOVA ranks).

CONCLUSION: The AGT polymorphism associated with fetal growth restr ict ion a n d adul t hypertensiort is taut associated with elevated insul in / glucose ratios in young healthy nulligravid women. These f indings do not support a link between the AGT TT polymorphism and insulin resistance as a genetic explanation for the "fetal origins" hypothesis.

571

December 2001 Am J Obstet Gynecol

ROLE OF UMBILICAL ARTERY CORD GAS PARAMETERS IN PREDICT- ING NEONATAL DEATH IN NEONATES WITH EARLY ONSET SEIZURES KEITH WILLIAMS 1, AVASH SINGH2; IYale University, Obstetrics and Gyne- cology, New Haven, CT; 2B C Childrens Hospital, Neonatology, Vancouver, British Columbia

OBJECTIVE: To correlate umbilical ar tery b lood gas parameters with neonatal death in neonates with early onset seizures secondary to Hypoxic lschemic Encephalopathy (HIE).

STUDY DESIGN: We reviewed the maternal and neonatal charts of 47 term neonates admit ted to NICU with HIE and early onset seizures with co rd b lood gases done. Patients were divided into two groups: 1. Infants with neonatal seizures who smwived. 2. Infants with neonatal seizures who expired related to HIE complications. Comparison of umbilical artery pH, PO2, PCO2, Base Deficit and neonatal death was done between the groups with student tests and multiple regression analysis.

RESULTS: Neither Cord ph nor Base Deficit was significantly different in the group that expired. The PO2 was significantly higher in the group that expired (Table). Multiple regression analysis showed that neonatal death was predicted only by elevated PCO2 and PO2.

CONCLUSION: In infants with HIE with seizures, nei ther the umbilical artery ph or base deficit is predictive of the poor outcome of neonatal death. The f inding of a high PO2 in neonates who expired is surprising and may indicate an inability of those infants to efficiently extract oxygen from blood.

Table

EXPIRED N O T EXPIRED SIGNIF

Number 14 33 Cord pH 6.89 + .15 6.94 ± 0.17 NS Base excess -17.04 _+ 5.34 -13.95 + 9.72 NS PCO2 109 _+ 31.88 94.9 + 36.27 NS PO2 18.36 +_ 9.15 12.33 + 7.51 .04 0 2 Sat 0.16 _+ .19 1.42 + 6.65 NS

570 THE CORRELATION OF NEWBORN SEIZURES DUE T O HYPOXIC IS- CHEMIC ENCEPHALOPATHY (HIE) IN NEONATES WITH SIGNIFICANT ACIDOSIS AT BIRTH WITH UMBILICAL ARTERY CORD GAS PARAME- TERS KEITH WILLIAMS 1, AVASH SINGH2; tyale University, Obstetrics and Gynecology, New Haven, CT; ~B C Childrens Hospital , Neonatology, Van- couver, British Colun-ibia

OBJECTIVE: To correlate umbilical ar tery b lood gas variables with neonatal seizures in neonates with significant acidosis at bir th (ph <7.1).

STUDY DESIGN: We reviewed the maternal and neonatal charts of 265 patients at gestational age >36 weeks with cord gases done at delivery and an umbilical artery p h <7.1. All infants transferred to the NICU were reviewed and those with neonatal seizures secondary to Hypoxic Ischemic Encephalopathy (HIE) identified. We used the perinatal outcome of early neonatal seizures secondary to HIE to divide the patients into two groups. The relat ionship between umbilical ar tery ph, base deficit, PO2 and PCO2 a n d neonata l seizures were determined with student tests and multiple regression analysis.

RESULTS: Umbilical artery Base Excess, PCO2 and PO2 were significantly elevated with newborn seizures, whereas cord ph was decreased (Table). Using mult iple regression analysis neonata l seizure was pred ic ted only by a low umbilical artery ph. A ph o f < 7 was more sensitive (73.8%) than a base deficit of -16 (52.5%) in predic t ing the development of neonata l seizures. Com- bining abnormal ph < 7 and base deficit > 16 did not predict perinatal out- come better.

CONCLUSION: Our data suggests that severe fi~tal acidemia identified by a ph of < 7.0 is the most important umbilical blood gas variable to predict early onset of neonatal seizures. Table

SEIZURES N O SEIZURES P

Number 40 225 Cord Ua pH 6.9 + .17 7.04 + .10 .004 Base deficit -14.96 + 8.57 -11.0 + 4.5 .0001 PO2 14.18 + 8.4 10.59 + 5.6 .01 PCO2 99.6 + 34.8 86.1 _+ 19.2 .018 0 2 Sat 1.018 + 5.5 0.129 _+ .107 .325

572 ELECTRICAL IMPEDANCE--A NOVEL APPROACH TO DETERMINE FETAL LUNG MATURITY MICHAEL P O ' C O N N E L L 1 , M VAN DER SCHUYFF 2, S W LINDOW3; tNational Maternity, Hospital, Dublin 2; 2UniveI~ sity of Cape Town, Cape Town; 3University of Hull, Obstetrics and Gynae- cology, Hull

OBJECTIVE: To assess fetal lung maturi ty using electrical impedance measurements of amniotic fluid and to compare these results with s tandard tests, (lecithin sphingomyelin ratio and bubble test), employed to assess fetal lung maturity.

STUDY DESIGN: One h u n d r e d and thirty-two women who underwent amniocentesis to estimate fetal lung maturity in Groote Schuur Hospital, Cape Town, gave written informed consent for a 5 ml sample of l iquor to be analyzed in the study. Eighty-five samples of immature l iquor were obtained from the Depar tment of Genetics, University of Leeds, following diagnostic second trimester testing for genetic disorders. Electrical impedence measurements on both sets of samples were obta ined by placing te t rapolar probes into the aliquots of amniotic fluid. A current of 10ktA was passed between 2 poles with the resultant potential being measured between the remaining two poles. In addition all samples had a bubble test performed. The Cape Town samples also had leci thin/sphingomyelin ratios performed.

RESULTS: Statistically significant correlations were noted at the .01 level when compar ing electrical impedance measurements with gestational age and the bubble test. The correlation between electrical impedance measurements and the l ec i th in / sph ingomyel in ratiowas signif icant at the .05 level. The correlations were seen with both the 5 mm and 8 mm probes.

CONCLUSION: This preliminary in vitro study demonstrates a potential ability for electrical impedance measurements of amniotic fluid to aid the determination of fetal lung maturity. However, the technology is complex and relatively expensive in the undex:developed and developing world setting, where amniocentesis for fetal lung maturity is commonly performed. Future work needs to explore the possibility to applying this technology to the in vivo setting in order to avoid amniocentesis.