Congenital Upper Limb Anomalies 181with amniotic membrane disruption and repair, can cause intrauterine
amputations or deformations of the limbs. (Chung, 2004).
Hyperthermia
Hyperthermia is defined as a body temperature of at least 38.9°C and has
been described as an antimitotic teratogen after exposure between weeks 4 and
14 (Gilbert-Barness, 2010). In a retrospective study, Smith and colleagues
presented 21 patients who had been exposed during pregnancy to hyperthermia
caused by infections or by sauna bathing. When the mothers were exposed to
hyperthermia between 4 and 6 weeks’ gestation, severe mental deficiency,
seizures in infancy, microphthalmia, midface hypoplasia, and mild distal limb
abnormalities were the most consistent manifestations observed in their
offspring. Between 7 to 16 weeks’ gestation, predominant features in the
offspring were hypotonia, neurogenic arthrogryposis, and central nervous
system dysgenesis (Smith et al., 1978).
PRENATAL DIAGNOSIS
There are many reasons supporting the use of prenatal testing to identify
and diagnose CULA and other congenital anomalies. Foreknowledge will
enable the parents to begin planning for a child with special needs, start
addressing anticipated lifestyle changes, identify support groups and resources,
and become aware of potential interventions that may be considered as well as
the decision whether to carry the gestation to term.
Non-Invasive Screening Tools
Ultrasound scanning is offered to pregnant women around 11 to 14 weeks
of gestation. An examination of fetal limbs is part of a routine scan. There are
several potential benefits of routine prenatal ultrasound scanning at 10 to 20
weeks. It causes little discomfort for mothers and is simply and quickly
performed. It has no adverse effects for the mother or fetus. It allows the
instigation of therapeutic intervention or informed termination of pregnancy.
Data from Kevern et al., used two different groups to study prenatal detection
rates of limb anomalies and the accuracy of prenatal diagnosis. The data
suggests low sensitivity of this technique (15/60 anomalies were detected);