383 OLDER MATERNAL AGE AND HIGHER PLURALITY: WHAT ARE THE RISKS?BARBARA LUKE1, MORTON B. BROWN2, University of Miami, Coral Gables,Florida, 2University of Michigan, Biostatistics, Ann Arbor, Michigan

OBJECTIVE: Since 1980, the percent of women ages 35 and older givingbirth has increased threefold for singletons, fourfold for twins, and sixfold fortriplets. Our objective was to evaluate the risks of complications withincreasing maternal age and increasing plurality.

STUDY DESIGN: The study population included pregnancies among womenages 25 and older from the 1995-2000 Birth Cohort Linked Birth/Infant DeathData Set for singletons and from the 1995-2000 Matched Multiple BirthData Set for twins and triplets: 14,359,932 singleton (SI), 234,996 twin (TW),and 11,240 triplet (TR) pregnancies. Maternal age groups included ages 25-29,30-34, 35-39, and 40C. Adjusted odds ratios (AORs) and 95% confidenceintervals were calculated to evaluate the risk 1) with increasing maternal agewithin each plurality, with ages 25-29 as the reference group; and 2) withincreasing plurality within each age group, with singletons as the referencegroup.

RESULTS: Within each plurality, increasing maternal age was associatedwith significantly higher risks of diabetes, chronic hypertension, pregnancy-associated hypertension, and eclampsia, but for multiples, lower risks oftocolysis (at 40C, SI-AOR 1.00 vs TW-AOR 0.67, TR-AOR 0.66), birth lessthan 29 weeks (at 40C, SI-AOR 1.62 vs TW-AOR 0.72, TW-AOR 0.52), andinfant mortality (at 40C, SI-AOR 1.44 vs TW-AOR 0.69, TW-AOR 0.29).Within age groups, increasing plurality was associated with significantly higherrisks of nearly all complications, often magnifying those associated withincreasing maternal age. For example, compared to singletons, the risk ofeclampsia among women ages 25-29 was TW-AOR 3.19, TR-AOR 4.21 versusTW-AOR 3.62, TR-AOR 6.78 among women ages 40C.

CONCLUSION: Older maternal age and higher plurality are each associatedwith increasing risks for many pregnancy complications. Despite this, com-pared to their younger counterparts, women ages 40C pregnant with multipleshad the lowest risks of tocolysis, early preterm delivery, and infant mortality.

384 IN IVF TWIN PREGNANCY, DOES A ‘‘VANISHING’’ TWIN LOWER OBSTETRIC RISK?GUOYANG LUO1, ROBIN B. KALISH1, PERNI SRIRAM1, STEPHEN CHASEN1, 1WeillMedical College of Cornell University, Obstetrics and Gynecology, NewYork, New York

OBJECTIVE: Our objective was to determine whether spontaneous reductionin IVF twin pregnancies results in obstetric outcomes comparable to IVFsingleton pregnancies.

STUDY DESIGN: Women with IVF pregnancies from 2003-2005 who had1st-trimester ultrasound and delivered in our hospital were identified. Thosewith documented reduction from dichorionic twins to a single viable fetus at!15 weeks were categorized as ‘‘vanishing twin’’ (VT) pregnancies, and werecompared to dichorionic twin and singleton pregnancies without reduction.Those with selective termination or fetal demise at R15 weeks were excluded.Charts were reviewed for obstetric and neonatal outcomes. Continuous datawere compared with Mann-Whitney U and Kruskal-Wallis test. Categoricdata were compared with Chi-square and Fisher’s exact test.

RESULTS: 124 singleton, 35 VT, and 50 twin pregnancies were included.There were no significant differences in maternal age or weight. Outcomes canbe seen in the Table, with statistical comparison made across the three groups.Gestational age at delivery was similar in the singleton and VT groups; twinsdelivered significantly earlier. Neonates from VT pregnancies weighed signif-icantly less than those from singleton pregnancies. The rate of small for gesta-tional age (SGA) neonates was highest in the twin group, with no significantdifference between the VT and singleton group (p=.23). There were no dif-ferences in the rates of preeclampsia, diabetes, or other obstetric complicationsbetween the three groups.

CONCLUSION: Spontaneous reduction of a twin to a singleton pregnancy isassociated with prolonged gestation and higher birthweight for the remainingfetus. Compared to singleton pregnancies without reduction, however, spon-taneous reduction is associated with lower birthweight.

Obstetric outcomes

Delivery data Singleton Vanishing twin Twin p value

Gest. age (weeks) 38.8G2.1 38.3G3.8 36.1G3.2 !.001Weight (g) 3336G606 3020G833 2490G447 !.001SGA 9.7% 17.1% 32.0% !.001

385 TWIN PREGNANCY IN ADVANCED MATERNAL AGE (AMA) WOMEN IS NOTASSOCIATED WITH INCREASED RATES OF ADVERSE NEONATAL OUTCOMESCECILIA LYONS1, MICHAEL HAYDON1, PAMELA RUMNEY1, DAVID LAGREW2, 1Uni-versity of California, Irvine, Obstetrics and Gynecology, Orange, California,2Saddleback Memorial Medical Center, Laguna Hills, California

OBJECTIVE: The prevailing opinion is that women who are AMA havepregnancies with poorer outcomes. Our aim is to determine if women of AMA(ageR 35) with twin pregnancies have worse neonatal outcomes as comparedto a group of younger controls (age!35).

STUDY DESIGN: A retrospective study of twin pregnancies at 3 hospitalsfrom1/1998-12/2004. There were 154 women age greater than 35 at deliveryand 146 women age less than 35 used as controls. Charts were reviewed formaternal demographics, method of conception and delivery outcomes. Statis-tical analysis was done using Student’s t test and Mann-Whitney Test.

RESULTS: Demographics were similar between groups aside from assistedreproduction which was used in 55% of the AMA patients and 21% of thecontrols. There were 308 infants delivered in the AMA group and 292 infantsdelivered in the control group. Outcomes for birthweight and Apgar scoreswere determined using live births.

The percentage of newborns admitted to the NICU was higher in the AMAgroup (47.2% vs 31% p!.0001), however, mean length of stay was higher inthe control group (17.6 vs 34.9 days p!.0001). There were a greater percentageof infants in the control group that were diagnosed with RDS (14% vs 8.9%p=0.05). There were no differences with respect to IVH, NEC, or sepsis. Therewere more previable infants delivered in the younger control group.

CONCLUSION: Outcomes in AMApatients were improved as compared to theiryoungercounterparts.AlthoughadmissionstotheNICUweremore likely intheAMAgroup, the lengthof stay in theNICUwas longer for the infants of youngermothers.

Gestational age at delivery %

Weeks at delivery Age !35 AgeR35 P-value

!28 10.3% 1.3% 0.001!32 17.1% 9.1% 0.04!35 35.6% 37.0% NS

Neonatal outcomes

Age!35 AgeR35 P-value

Mean birthweight 2317 2457 0.03!2500g 56.6% 48.7% 0.057!1500g 12.1% 7.2% 0.05Apgar 1 min !5 12.5% 6.6% 0.016Apgar 5 min !7 6.4% 3.0% 0.05

386 PROPOSAL FOR A STANDARDISED CLASSIFICATION SYSTEM FOR AUDIT OF INDUC-TION OF LABOUR. HELEN MC MILLAN1, TOMWALSH2, MICHAEL GANNON3, RICHARDHORGAN3, NAVEED KHAWAJA3, CLAIRE COLLINS4, MICHAEL GEARY1, 1RotundaHos-pital, Dublin, Dublin, Ireland, 2Royal College of Surgeons, Limerick, Ireland,3Rotunda Hospital, Dublin, Ireland, Obstetrics & Gynaecology, Dublin, Ire-land, 4Rotunda Hospital, Epidemiology, Dublin, Ireland

OBJECTIVE: -To propose a classification system for performing an audit ofinduction and to demonstrate its application.

STUDY DESIGN: This was a 6-month prospective observational study analyz-ing the outcomes of IOL . Demographics, the indication for IOL, the Bishopsscore and use of prostaglandin were recorded. We classified the indicationsas- 1)Post-date pregnancy, 2) Medical, 3) Prelabour Rupture of Membranes(PROM), 4) Oligohydramnios, 5) Placental indications, 6) Others, 7) Social.

RESULTS: 584 women were included in the trial. The outcomes for mode ofdeliverydependingonindicationforIOLandparityare shown inTable1. (*p!0.01significant differences bewteen parity for each respective indictation annotated.)

CONCLUSION: ‘‘Social’’ inductions have a high emergency CS rate of 44.4%for nulliparas and 14.8% for multiparas; the SVD rate for nulliparous womenwas 16.7%. Those induced for oligohydramnios have an emergency CS rate of64.0% for nulliparas and 31.6% for multiparas. In this scenario there may be anargument for considering an elective CS for these nulliparas. The classificationgroups proposed have endeavored to achieve mutually exclusive groupings,using easily accessible information. The resulting data is pragmatically useful.

Mode of delivery considering indication for induction of labour and parity

Indication type Delivery Nullip N (%) Multip N (%)

Postdates* SVD 33 (25.8%) 104 (83.9%)V/F 41 (32.0%) 8 (6.5%)CS 54 (42.2%) 12 (9.7%)

Social* SVD 3 (16.7%) 39 (72.2%)V/F 7 (38.9%) 7 (13.0%)CS 8 (44.4%) 8 (14.8%)

Placental* SVD 11 (27.5%) 22 (88.0%)V/F 9 (22.5%) 0CS 20 (50.0%) 3 (12.0%)

Medical* SVD 3 (15.8%) 24 (82.8%)V/F 7 (36.8%) 3 (10.3%)CS 9 (47.4%) 2 (6.9%)

Oligo SVD 7 (28.0%) 11 (57.9%)V/F 2 (8.0%) 2 (10.5%)CS 16 (64.0%) 6 (31.6%)

SMFM Abstracts S115