Pregnancy Outcome Patterns for Selected Birth Defects in Texas

1
Pregnancy Outcome Patterns for Selected Birth
Defects in Texas

• Mary Ethen, MPH
• Amy Case, MAHS
• Texas Birth Defects Monitoring Division

2
Features of the Texas Birth Defects Registry

• Active surveillance--trained staff visit
  facilities to collect information
• Coverage of more than 365,000 live births
  annually (statewide)
• Computerized database of infants and pregnancies
  affected by birth defects
• Emphasis on structural malformations
• Cases matched to vital record

3
Texas Birth Defects Registry Case Definition

• Mother resides in Texas at delivery
• Includes live births, fetal deaths, and elective
  terminations of any gestational age
• Infant/fetus must have one or more structural or
  chromosomal birth defects, or Fetal Alcohol
  Syndrome
• Defect must be diagnosed within the first year
  after delivery (within six years for Fetal
  Alcohol Syndrome)

4
Methods

• Deliveries in the Texas Birth Defects Registry
  that occurred 1999-2000
• Forty-nine major defect categories
• Gestational age calculated from last menstrual
  period (LMP) or neonatal examination

5
Methods

• Pregnancy outcome based on information abstracted
  from medical records
• Registry records matched to vital records
• 97 agreement between pregnancy outcome
  (Registry) and type of vital record matched

6
Live Birth

• Complete expulsion or extraction a product of
  conception
• Any gestational age
• After delivery, shows any vital signs (heartbeat,
  voluntary breathing, umbilical cord pulsation,
  voluntary muscle movement)
• Most common outcome by far of Registry cases

• 100 of Cases in Registry were Live Birth for
  these Defects
• Cataract
• Aniridia
• Hirschsprung Disease
• Biliary Atresia
• Bladder Exstrophy
• Congenital Hip Dislocation
• FAS

7
Fetal Death

• Spontaneous death of a product of conception
  prior to the complete expulsion or extraction
  from its mother.
• Onset of labor may be natural or induced.
• Also referred to as spontaneous abortion,
  miscarriage or stillbirth.
• Outcome in 1.83 of Texas infants and fetuses
  with a birth defect.

• Examples (any gestational age)
• Anencephaly (21.7)
• Holoprosencephaly (10.5)
• Anophthalmia (14.3)
• Lower Limb Reduction (10.5)
• Omphalocele (12.0)
• Trisomy 13 (10.5)
• Trisomy 18 (11.6)

8
Induced Termination

• After pregnancy is medically verified
• Intended to terminate intrauterine pregnancy
  (other than for the purpose of either the birth
  of a live infant or the removal of a dead fetus)
  
• Also referred to as
• induced abortion
• therapeutic abortion
• elective abortion
• elective termination
• Outcome in 2.32 of Texas infants and fetuses
  with a birth defect

• Examples (any gestational age)
• Anencephaly (48.9)
• Encephalocele (28.6)
• Holoprosencephaly (17.11)
• Anophthalmia (33.3)
• Omphalocele (16.4)
• Trisomy 13 (24.2)
• Trisomy 18 (40.7)

9
Pregnancy Outcome Gestational Age Categories

• Live Birth, Any Gestational Age
• Fetal Death lt20 Weeks Gestation
• Fetal Death 20 Weeks Gestation

• Induced Termination, lt20 Weeks Gestation
• Induced Termination, 20 Weeks Gestation
• Unspecified fetal death or medical termination

10
Factors that May Influence Pregnancy Outcome

• Mothers health (infections, treatment for
  chronic conditions)
• Prenatal diagnosis
• Prognosis for Child
• Lethality of defect
• Degree of impairment
• Expectation of health
• Co-occurring defects

• Others?
• __________________________
• __________________________
• __________________________

11
Infants and Fetuses with Any Monitored Defect
GA Gestational Age
12
Pregnancy Outcomes for Selected Neural Tube
DefectsTexas, 1999-2000
13
Pregnancy Outcomes for Selected Chromosomal
Defects (Trisomies), Texas, 1999-2000
14
Pregnancy Outcomes for Selected Abdominal Wall
DefectsTexas, 1999-2000
15
Pregnancy Outcomes for Selected Defects, Texas,
1999-2000
16
Reduction Defects of the Lower Limbs
17
Pregnancy Outcome Other than Live Birth, by
Maternal Race/Ethnicity
18
Percent of Cases Resulting in Induced
Termination by Maternal Race/Ethnicity
19
Percent of Cases Resulting in Fetal Death by
Maternal Race/Ethnicity
20
Limitations

• Possible misclassification of pregnancy outcomes
• Difficult to determine intended outcome from
  medical record
• Lethal/non-lethal conditions in the same defect
  group (e.g. renal agenesis/ dysgenesis)

• Birth defects among early fetal deaths
  (miscarriage) and early terminations likely to be
  under-ascertained
• Less severe defects co-occur with more severe
  defects
• Analysis not restricted to isolated defects

21
Acknowledgements

• TBDMD Surveillance Staff
• Texas Department of Health Bureau of Vital
  Statistics
• Mark Canfield, Ph.D., Director, Texas Birth
  Defects Monitoring Division