الفهرس 
Review of literatureOnly 14 pages are availabe for public view
 |  | from | 195 |  |  |
| | | from | 195 | | |
Abstract
Spontaneous preterm birth before 37 weeks’ gestation occurs in 7-11% of
pregnancies and before 34 weeks in 3-7% of pregnancies .The latter is more likely
to be due to pathological than physiological causes.
Preterm delivery, particularly before 34 weeks of gestation, accounts for
three-quarters of neonatal mortality and one-half of long-term neurological
impairment in children.
Risk prediction for preterm birth both for screening and diagnosis is based
on a combination of patients’ characteristics, symptoms, physical signs and
investigations.
Risk scoring, maternal anthropometry, ultrasound measurement of cervical
length, cervicovaginal fetal fibronectin (fFN), and testing for bacterial vaginosis
infection (BV), have been evaluated for their utility in predicting preterm birth.
The studies on these tests generally used preterm birth before 36 weeks’ gestation
as the outcome. Only cevicovaginal fFN and cervical length were also considered
for birth before 34 weeks’ gestation.
Fetal fibronectin is found in high concentrations in the amniotic fluid and in
the i Its function during pregnancy is likely the maintenance of the choriodecidual
extracellular matrix. It acts as the glue that attaches the fetal membranes to the
underlying uterine deciduas. It may also play a role in placental cleavage following
delivery nterface between the deciduas and the trophoplast cells. The fFN is often
found in the cervicovaginal secretion before 16-18 weeks of gestation, and again at
the end of normal pregnancy as labor approaches.
146
The aim of this work is to assess the cervicovaginal fetal fibronectin (fFN)
level in the gestational age between 22-26weeks in women with cervical cerclage
as a predictive method for preterm delivery before 36 weeks.
This study was carried out at Ain Shams University Maternity Hospital
during the period from November 2010 to September 2012. Women approached in
this study are those in antenatal out patient’s clinic and those admitted to the
antepartum inpatient high risk service.
The study is a prospective cohort study; the calculation of sample size was
performed by MedCalc® version 7.4 computer software. It was found that at least
98 patients with cervical cerclage are needed at the start of the study to detect a
difference of at least 30% in the incidence of preterm delivery with significance
level of 0.05 and power of 0.8.
Fetal fibronectin testing was done for all women with cervical cerclage at
gestational age between 22 to 26 weeks then the women are divided into two
groups; group (1) which included approximately 49 women with cerclage and fFN
negative, group (2) which included approximately 49 women with cerclage and
fFN positive.
The test will be done during the regular antenatal examination via taking a
sample of the vaginal discharge with a sterile plastic pipette under complete aseptic
conditions. Follow up for patients will be done via taking another appointment for
their next visit to the antenatal care clinic till the time of delivery, and by telephone
number to be informed about of time of current delivery.
The participating women were subjected to sterile speculum examination for
collection of cervico-vaginal sample for fetal fibronectin assay.
147
Radial immunodiffusion (RID) was used for the purpose of fibronectin assay
in this study.
The method involved antigen diffusing radially from the cylindrical well
through an agarose gel containing an appropriate mono-specific antibody.
Demographic variables assessed at the study for each group were maternal
age, gestational age at sampling, parity, number of previous cerclage, number of
previous abortions, number of preterm labor, number of term labor and gestational
age at current delivery.
Maternal age at sampling, gestational age at sampling, parity, number of
previous cerclage, number of previous abortion, number of previous preterm
delivery and number of previous term delivery all showed no significant difference
between the two groups with p˃0.05, but the only demographic variable that
showed an evident significant difference between the two groups with p˂0.001 is
the gestational age at current delivery which is considered preterm when occurred
before 36 weeks of gestation as based on the current study.
The diagnostic power of fFN in prediction of preterm labor (95% confidence
interval) showing that its specificity is 64.0% (54.3-72.6%) , sensitivity is 64.6%
(54.5-73.5%), with negative predictive value of 65.3%, positive predictive value of
63.3% and with efficacy of 64.3%.
The results of the study revealed that they were 34.7% of women with fFN
negative were delivered at gestational age less than 36 weeks, and they were 65.3%
of them were delivered full term. While they were 63.3% of women with fFN
positive were delivered prior to 36 weeks of gestation and 36.7% of them are
delivered full term.