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Newborn Care and Newborn Infant

Indications for Prenatal Diagnostic Testing for Birth Defects

Cytogenetic Indications

1. Advanced maternal age (>35 yrs)
2. Previous offspring with chromosome abnormality, especially trisomy
3. Chromosome abnormality in either parent, especially translocation
4. Need to determine fetal sex when there is a family history of serious X-linked disease

Single gene disorder in a sibling or carrier parent

Multifactorial disorder in first-degree relatives

Routine Assessment of Intrauterine Growth and Maturation

Document maturity and EDC

1. Documentation of fetal heart tones for 30 weeks by Doppler ultrasound.
2. 36 weeks of positive pregnancy test (HCG).
3. Ultrasound examination documenting one of following:
1. Crown rump length between 6-11 weeks
2. Evaluation at 12-20 weeks that confirms clinical history and physical examination

Assessment of Continued Growth

1. Crown rump length, femur length, chest and abdominal circumference, head circumference

Assessment of Pulmonary Maturity

1. Presence of phosphatidylglycerol (PG) indicates maturity.
2. A ratio of lecithin to sphingomyelin (L:S) ratio >2 is consistent with maturity
3. Foam stability index: complete bubble ring indicates maturity
4. Delta optical density 650 >0.15 indicates maturity

Assessment of Placental Integrity

1. Ultrasound evaluation of placenta and fetus (location, size, morphology)
2. Doppler Flow Studies. Assessment of blood flow velocity in uterus, placenta, cord vessels, and fetal aorta/carotid arteries. May be useful in conditions of compromised blood flow (eg, IUGR, hypertension, diabetes mellitus and postmaturity). Elevated systolic:diastolic umbilical artery velocity ratio, elevated pulsatility index and reduced end-diastolic flow velocity suggest fetal distress.

Periumbilical Blood Sampling (PUBS)

1. HCT determination
2. Rapid karyotype
3. Platelet assessment
4. Acid-base assessment
5. Biochemical and serologic studies

Intrapartum Assessment