Please select the eligibility criteria that correspond to the clinical trial below.
Title: Nifedipine Compared to Atosiban for Treating Preterm Labor. A Randomized Controlled Trial.
Brief Summary: The purpose of this study is to investigate the efficacy and the safety of nifedipine compared to atosiban for treating preterm labor.


Options:
A: Inclusion Criteria:

1. Twin pregnancy
2. Gestational age between 24+0 and 32+6 weeks
3. Intact amniotic membranes
4. Threatened preterm labor
5. Age 18-50.

Exclusion Criteria:

1. Rupture of membranes
2. Vaginal bleeding resulting from placenta previa or placental abruption
3. Fever above 38°C
4. Severe preeclampsia
5. Maternal cardiovascular or liver diseases
6. Systolic blood pressure less than 90 mm Hg
7. Known uterine malformation
8. Intrauterine growth restriction below the fifth percentile
9. Non-reassuring fetal status
10. Antepartum diagnosis of major fetal malformations
11. Fetal death
12. Previous tocolytic therapy or Betamethasone treatment
B: Inclusion Criteria:

* Initial episode of preterm labor for enrollment
* The diagnosis of preterm labor
* Gestational age between 24 and 32 weeks
* Singleton or twin gestation
* The ability to understand the requirements of the study

Exclusion Criteria:

* Cervical dilation \>5 cms
* Suspected chorioamnionitis
* Fetal distress
* Vaginal bleeding
* Severe pre-eclampsia
* History of gastrointestinal bleeding
* Abnormal renal function
* Suspicion of fetal malformation by ultrasound
* Known allergy to, or intolerance of, Magnesium sulfate and/or Indomethacin
* Documented rupture of amniotic membranes
* Multiple gestations of triplets or more.
C: Inclusion Criteria:

The study population and the inclusion criteria is established by patients between the 24th and 33+6th weeks of pregnancy, fixed by an ecography during the first three-month period, and with a threat of preterm labor (TLP), by the American College of Obstetricians and Gynecologists (ACOG's) criteria:

* Four contractions or more with a duration of at least 30 seconds during 30 minutes
* Documented cervix changes:

  * The cervix changes in a nulliparous woman are: both cervix tact with 0 to 4 cm of dilatation and cervical effacement of at least a 50% (vaginal ultrasound alternative with cervix length two standard curvatures under the average for the gestational age)
  * The cervix changes in a multiparous woman are: 1 to 4 cm of dilatation and cervical effacement of at least a 50% (same ecographic alternative as the nulliparous).
* Patient who had signed the informed consent.

Exclusion Criteria:

Exclusion criteria of the pregnant mother and intrauterine fetal:

* Prior treatment with a different tocolytic from the ones in the protocol.
* Chorioamnionitis.
* Premature rupture of membranes.
* Vaginal Bleeding.
* Major fetal malformations.
* Intrauterine growth retardation (IGR): IGR\<percentile 5.
* Cardiopathies (aortic stenosis, congestive heart failure).
* Blood Pressure lower than 100/60 mmHg.
* High transaminase levels.
* Uterine malformations.
* Use of magnesium sulphate.
* Severe hypertensive disorder, defined as blood pressure equal to or greater than 160/100 mmHg or any figure associated with severe preeclampsia.
* Non-reassuring cardiac frequency tracing defined as category II and III of National Institute of Child Health and Human Development (NICHD).
* Asthmatic patients treated with betamimetics.
* Hypertensive patients treated with vasodilators.
* Patient in treatment or treated with another product/s in investigation during the four weeks prior to randomization.
* Hypersensitivity to any drug of the study.
D: Inclusion Criteria:

1. Gestational age between 24 to 34 weeks which had been documented by a definite LMP and sonography up to 20 weeks.
2. All women fulfilled the criteria of preterm labor. The diagnosis of preterm labor required the presence of 4 uterine contractions or more over 30 minutes, each lasting at least 30 seconds, and documented cervical change. The cervical criteria were met when either of the following was present:

   1. Nulliparous women: a single cervical examination demonstrating dilatation of 0 cm to 4 cm and effacement of at least 50%
   2. Multiparous women: a single cervical examination demonstrating dilatation of 1 cm to 4 cm and effacement of at least 50%.
3. Provision of written informed consent

Exclusion Criteria:

1. Chorioamnionitis
2. Preterm rupture of membranes
3. Vaginal bleeding
4. Major fetal malformations
5. Severe hypertensive disorders
6. Intrauterine growth restriction (\< 5th percentile).
7. Non-reassuring fetal heart rate
8. Maternal contraindications

   1. Chronic hypertension
   2. Systolic blood pressure \< 90 mmHg
   3. Cardiovascular disease
   4. Elevated hepatic enzymes
9. Congenital or acquired uterine malformation

Answer: D