3. RESULTS
A total of 447 amniocentesis specimens were processed
during the study period. The mean (± SD) maternal age
was 31.82 ± 6.30 years. The major indications for amniocentesis
were positive maternal triple screening
(44%), advanced maternal age with positive maternal
triple screening (18.9%) and advanced maternal age
solely (15.5%) (Table 1). The mean (± SD) gestational
age at amniocentesis was 18.80 ± 2.70 weeks. The mean
(± SD) gestational age at delivery was 38.06 ± 2.44, and
the mean (± SD) birthweight was 3261.30 ± 850.40 g.
Cytogenetic analysis revealed an abnormal karyotype
in 19 pregnancies (4.3 %), nine of them being trisomy 21
(Table 2).
The overall spontaneous loss rate at less than 24
weeks of gestation was 0.89% (n = 4), and 41 preterm
deliveries (9.2%) before 37 weeks of gestation occurred.
Fifteen (3.4%) patients experienced preeclampsia. The
rate of low birthweight (< 2500 g) infants was 8.6%
(Table 3).sis