UNSW Embryology

Abnormal Development - Australian Statistics -Victoria

© Dr Mark Hill (2009)

Acknowledgements

Introduction

This current page shows the ten most frequently reported birth defects in the Australian state of Victoria between 2003-2004.

1. Hypospadias (More? Genital Abnormalities - Hypospadia)
2. Obstructive Defects of the Renal Pelvis (More? Urogenital Abnormalities)
3. Ventricular Septal Defect (More? Cardiovascular Abnormalities - Ventricular Septal Defect)
4. Congenital Dislocated Hip (More? Musculoskelal Abnormalities - Congenital Dislocation of the Hip (CDH))
5. Trisomy 21 or Down syndrome - (More? Abnormal Development - Trisomy 21)
6. Hydrocephalus (More? Neural Abnormalities - Hydrocephalus)
7. Cleft Palate (More? Head Abnormalities)
8. Trisomy 18 or Edward Syndrome - multiple abnormalities of the heart, diaphragm, lungs, kidneys, ureters and palate 86% discontinued (More? Abnormal Development - Trisomy 18)
9. Renal Agenesis/Dysgenesis - reduction in neonatal death and stillbirth since 1993 may be due to the more severe cases being identified in utero and being represented amongst the increased proportion of terminations (approximately 31%). (More? Kidney Abnormalities - Renal Agenesis)
10. Cleft Lip and Palate - occur with another defect in 33.7% of cases. (More? Head Abnormalities)

(Data from the Victorian Perinatal Data Collectionn Unit)

(More? Australian Statistics)

Neural Tube Defects

Neural tube defects that were just outside the top ten most common birth defects but are widely known.

Spina Bifida - (73%) of parents choose to discontinue a pregnancy affected by spina bifida.

Anencephaly - (94%) of parents choose to discontinue a pregnancy affected by anencephaly.

(Data from the Victorian Perinatal Data Collectionn Unit)

Birth Abnormality Factors

What factors influence the prevalence of birth defects? As well as sex of the child and the number of fetuses (twins, triplets, quads), the Birth Defects Register also collects maternal information such as the mother’s country of birth, region of residence and age. Some of these factors have been shown to influence the chance of having a baby with a birth defect.

Maternal age

The frequency of birth defects is highest among mothers aged 35 years and over. These women have almost a one and a half times increased risk of having a pregnancy affected by a birth defect compared to younger women. By the time a women is 40 years and over her chance is almost twice as high (7.4%). Hydrocephalus, ventricular septal defect, cleft palate, cleft lip and palate, congenital dislocated hip, trisomy 21 and trisomy 18 are all more likely to occur with older mothers. Younger maternal age was significantly associated with all neural tube defects, and obstructive defects of the renal pelvis.

Sex Female babies are more likely to have a birth defect than male babies; 4.7% of males compared with 3.7% of female babies had a birth defect in 2003-2004.

Plurality Multiple births (twin, triplets, and quads) are also slightly more likely to be affected by a birth defect than singleton births; 5% of multiple births had a birth defect compared to 4.3% of singleton births that had a birth defect.

(Data and Text from the Victorian Perinatal Data Collectionn Unit)

Quick Links

Development Notes ----------------- Menstrual Cycle Week 1 Week 2 Week 3 Week 4 Placenta Serial Images Genes/DNA Molecular Dev Abnormal Dev Postnatal Dev Notes Index

System Notes ----------------- Heart/Cardiovascular Respiratory Coelomic cavity Gastrointestinal Tract Head and Neck Neural Neural Crest Eye Ear Nose Endocrine Urogenital Musculoskeletal Integumentary

Movies ----------------- Embryo Growth Carnegie Stages Ultrasound Images Stage 13/14 Embryo Stage 22 Embryo Heart Septation Neural Neural Crest Other Embryos Larsen Movies

Other Embryos ----------------- Chicken Fly Frog Mouse Rabbit Rat Worm Zebrafish Guinea Pig

Glossary of Terms

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UNSW Embryology ISBN: 978 0 7334 2609 4

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