Please select the eligibility criteria that correspond to the clinical trial below.
Title: Comparison of Nifedipine Versus Indomethacin for Acute Preterm Labor
Brief Summary: The purpose of this research study is to determine the best medication to stop preterm labor. Recent studies have identify nifedipine and indomethacin as the two medications that are most likely to delay delivery for 48 hours, decrease maternal side effects and decrease some complications related to preterm delivery to the neonate. Both of these medications are commonly used to stop pre-term labor, therefore it has become our institution's standard to use these two medications in the setting of preterm labor. There have been limited studies comparing these two medications directly.

A total of 450 participants will be asked to participate across all study sites.


Options:
A: Inclusion Criteria:

* Gestational age of 24+0 to 34+6weeks
* singleton and twin pregnancies
* preterm labor with more than 4 times of uterine contraction for 20 minutes or more than 8 times for 1 hour on external tocography
* cervical dilatation of 0 to 3cm and cervical ripening more than 25%, or cervical length in sonography below 2cm

Exclusion Criteria:

* triplet etc
* preterm premature rupture of membrane
* cervical dilatation more than 3cm
* history of cerclage operation during this pregnancy
* placenta previa
* severe hypertensive diseases in pregnancy
* history of administration of any tocolytics 12 hours before enrollment
* fever more than 38.0'c
B: Inclusion Criteria:

* Between 16 and 44 years of age inclusive
* Singleton pregnancy
* Intact membranes
* Between 28-0/7 weeks and 33-6/7 weeks' gestation inclusive
* Reported or documented uterine activity
* Cervical dilation between 2 cm and 4 cm inclusive

Exclusion Criteria:

* Multifetal gestation
* Less than 28 weeks' gestation
* 34 or more weeks' gestation
* Ruptured membranes
* More than 4 cm dilated
* Previously received a course of corticosteroids for fetal lung maturation
* Oligohydramnios
* Fetal growth restriction
* Chorioamnionitis or temperature of at least 38.0 degrees Celsius
* Fetal death
* Preeclampsia
* Suspected placental abruption or placenta previa
* Lethal fetal malformation or amniotic fluid index at least 35
* Systolic BP \< 90 mmHg or diastolic BP \< 50 mmHg
* Baseline tachycardia (pulse \>120 after 2 consecutive measurements 30 minutes apart)
* Chronic hypertension treated with antihypertensives in pregnancy
* Seizure disorder or HIV
* Maternal allergy to nifedipine
* Known maternal cardiac disease
* Women who have received progesterone therapy in the second or third trimester for prevention of preterm birth
C: Inclusion Criteria:

* Singleton pregnancy. A twin pregnancy reduced to singleton (either spontaneously or therapeutically) before 140 weeks by gestational age (see dating below) is acceptable.
* Gestational age at randomization between 240 weeks to 315 weeks by using the dating determinations as below
* Preterm labor with intact membranes. Preterm labor is defined as at least 6 regular uterine contractions in 60 minutes either seen on tocodynamometer, palpated by health providers and/or subjectively felt by the patient and at least one of the following:

  1. Associated with cervical change by cervical dilation greater than or equal to 1cm OR effacement greater than or equal to 25 to 50%
  2. Cervix greater than or equal to 2cm dilated on initial digital exam
  3. At least 75% effaced on initial digital exam
  4. Short cervical length (defined by each institution's policy) as obtained by transvaginal cervical sonography \[in general, this is defined as a measurement of 2.0 - 2.5 cm or less\] and/or a positive fetal fibronectin test (defined as a level greater than 50ng/mL).
* Intact membranes
* 18 years of age or older

Exclusion Criteria:

* Fetal demise, or known major fetal anomaly, including cardiac anomaly and hydrops
* Maternal contraindication to nifedipine: preload cardiac lesions or maternal hypotension (systolic blood pressure less than 100 or diastolic blood pressure less than 60). A delayed dose can be given if blood pressure improves - it will be documented if dose is delayed, how long from scheduled dose it was delayed and reason for delay.
* Maternal contraindication to indomethacin: platelet dysfunction or bleeding disorders, hepatic dysfunction, gastrointestinal ulcerative disease, renal dysfunction and asthma
* Obstetrical contraindication to tocolysis not already mentioned: non reassuring fetal status, severe preeclampsia or eclampsia, maternal bleeding with hemodynamic instability, chorioamnionitis, preterm premature rupture of membranes
* Participation in another interventional study that influences neonatal morbidity or mortality
* Participation in this trial earlier in the pregnancy
* Maternal allergy to either indomethacin or nifedipine
* Maternal allergy to aspirin and other NSAIDs.
* Maternal hypertension requiring treatment.
* Maternal kidney disorder that would require adjustment in magnesium dosing.
D: Inclusion Criteria:

* Women in preterm labor between 24 to 32 6/7 weeks' gestation with intact membranes with an age range of 15 to 50 years old.

Exclusion Criteria:

* Cervical dilatation of ≥ 6 cm
* Maternal contraindication to tocolysis
* Known fetal anomalies
* Suspected chorioamnionitis
* Nonreassuring fetal heart tracing
* Vaginal bleeding due to placenta previa or abruptio placenta
* Preterm premature rupture of membranes
* Prolapsed membranes
* Human immunodeficiency virus positive
* Multiple gestation
* Patients on procardia within 24 hours of po intake
* Magnesium sulfate tocolysis prior to randomization
* Patient refusal

Answer: C