Please select the eligibility criteria that correspond to the clinical trial below.
Title: Comparative Study on Tocolysis in Prevention of Preterm Labour
Brief Summary: Preterm birth is defined as birth before 37 completed weeks of gestation .it occurs in 11.1%of birth globally affecting an estimated 14.9 million babies every year . It is generally accepted that approximately 65%-70%of preterm births are spontaneous,40%-45% of them due to spontaneous preterm labor and 25%-30%following preterm rupture of membranes.preterm birth represents the single largest cause of morbidity and mortality for newborn and is estimated for 29%of deaths in the first four weeks of life and also is estimated for of major cause of morbidity for pregnant women .

Tocolytic agents include a wide range of drugs that can slow or suppress uterine contractions . Tocolytic are considered advantages in spontaneous preterm labor to : (a) allow time for the fetus to mature ,potentially avoiding deleterious effects of pre-maturity . (b)allow time for antenatal corticosteroids to be administered and have clinical effect. (c) allow time for intrauterine transfer to higher-care center where neonatal intensive care facilities are available . the ideal Tocolytic agent should be effective , easy to administer , without significant material ,fetal or neonatal side effects and permit time for antenatal corticosteroids to be administered and take effect . a variety of Tocolytic treatments have been used to inhibit uterine activity in women in spontaneous preterm labor , including betamimetics , calcium channel blockers , magnesium sulfate , prostaglandin inhibitors and oxytocin receptor antagonists however there is considerable global variation in types , doses and regimens of tocolytic agents uses to manage preterm labor .

A comparison study between Ritodrine, magnesium sulfate and Nifedipine in terms of effect and morbidity will be conducted.


Options:
A: Inclusion Criteria:

* Pregnant women with singleton pregnancies and intact membranes which have passed an episode of threatened preterm delivery (uterine contractions with cervical change) successfully treated with atosiban as acute tocolytic therapy.
* Cervical length ≤ 25 mm.

Exclusion Criteria:

* ≥ 3 cm cervical dilation, multiple pregnancy, maternal medical contraindication to tocolysis with nifedipine, atosiban or progesterone, or obstetric contraindication to tocolytic treatment (severe preeclampsia, intrauterine infection, placental abruption, fetal abnormality incompatible with life, fetal death)
B: Inclusion Criteria:

* Patients between 240/7-320/7 weeks gestation with findings consistent with preterm labor defined by at least one of the following criteria in accordance with regular uterine contractions (\>4 uterine contractions in 20 minutes):

  1. Cervix \> 2 cm in dilation or 80% effaced
  2. Positive fetal fibronectin (if performed).
  3. Demonstrated cervical change between two exams within 90 minutes.

Exclusion Criteria:

* Negative fetal fibronectin
* \> 5cm dilatation
* Multiple gestations
* Known fetal anomalies or chromosomal abnormalities
* Ruptured membranes
* Significant vaginal bleeding
* Suspected chorioamnionitis
* Preeclampsia or uncontrolled hypertension
* Non-reassuring fetal heart tracing
* Placenta previa and/or accreta
* Placenta abruption
* Intrauterine growth restriction
* Maternal renal disease
* Underlying maternal cardiac condition
* Symptomatic hyperthyroidism
* Significant maternal disease
* Contraindication to nifedipine or magnesium
* Cerclage presence
* Tocolytic use within the last 12 hours
* Hypotension (defined as average blood pressure of \<70/40's unresponsive to 1000 cc fluid bolus
C: Inclusion Criteria:

* . Gestational age between 24-37weeks

  * Symptoms such as low backache , cramping ,pelvic pressure, excessive vaginal discharge and vaginal spotting .
  * Regular uterine contractions at least of 30 seconds duration at a rate of more than 4/30 minutes
  * Cervical changes dilatation less than 3cm,effacement lessthan50%.
  * Intact membranes.

Exclusion criteria

* Active vaginal bleeding and placental abruption.
* Chorioamnionitis and intrauterine infection
* Fetal conditions : fetal death or distress, lethal congenital or chromosomal abnormalities and intra uterine growth restriction
* Maternal conditions indicate that pregnancy shouldn't be continued: eclampsia , severe preeclampsia and cardiac diseases
* Drug specific contraindications(contraindication of tocolysis)
D: Inclusion Criteria:

• Singleton pregnancy women between 22 and 34 weeks of gestation who presented with threatened preterm labor.

Exclusion Criteria:

* Multiple pregnancies
* Women with Preterm Prelabour Rupture of Membrane
* Fetal death
* Women with bad obstetric history
* Women with history of cervical incompetence
* Contraindication to Nifedipine such as cardiovascular disease, hyperthyroidism, severe pre eclampsia or to Utrogestan
* Maternal or fetal indication for immediate delivery, such as fetal distress, bleeding placenta previa, abruption placenta
* Contraindication for tocolysis, for example severe pre eclampsia, intrauterine growth restriction, fetal anomaly, chorioamnionitis, significant antepartum haemorrhage
* Cervical dilatation of 3cm or more
* Patients with previous tocolytic treatment during this pregnancy
* Women who refuse to participate in this study

Answer: C