Please select the eligibility criteria that correspond to the clinical trial below.
Title: Up-down Determination of the ED90 of Oxytocin Infusions for the Prevention of Postpartum Uterine Atony in Parturients Undergoing Cesarean Delivery
Brief Summary: This study is designed to determine the minimum effective dose (ED90) of infusions of oxytocin for the prevention of uterine atony / postpartum hemorrhage and the need for additional uterotonics, in low risk parturients presenting for an elective CD.

The primary outcome measure is the response of effective uterine contraction as either satisfactory or unsatisfactory as determined by the obstetrician blinded to the oxytocin infusion dose. Secondary outcomes will include need for additional uterotonics, calculated intra-operative blood loss and presence of oxytocin related adverse effects.


Options:
A: Inclusion criteria:

* Singleton pregnancy
* Gestational age more than 36 weeks
* No contractions reported within the last 24 hours
* No contractions recorded by 30 min cardiotocogram prior to oxytocin challenge test

Exclusion criteria:

* All contraindications for labor, including placenta praevia
* Serious fetal malformations
* Anhydramnios
* Oligohydramnios
* IUGR \< 5. percentile
* Presence of any contractions
* Suspicious or pathological fetal heart rate tracing (cardiotocogram)
* Any clinical or biochemical signs of maternal infection
* Breech presentation
* More than 1 C-section in history
B: Inclusion Criteria:

* Study subjects will be women delivering via an elective cesarean section at term
* All study subjects will have singleton gestation with no obstetric or medical complication.

Exclusion Criteria:

* Laboring women
* Multifetal gestation
* Prolonged oxytocin use (\>12 hours)
* Hypertensive disorders
* Chorioamnionitis
* Suspected macrosomia
* Polyhydramnios
* History of postpartum Hemorrhage
* Clotting disorder
* Intake of magnesium sulfate
* Uterine fibroids
* Placenta previa
* Placental abruption
* Anticoagulation
C: Inclusion Criteria:

* All patients planned for elective cesarean delivery under spinal anesthesia;
* All patients who gave written informed consent to participate in this study.

Exclusion Criteria:

* All patients who refuse to give written informed consent.
* All patients who claim allergy or hypersensitivity to carbetocin or oxytocin.
* All patients with conditions that predispose to uterine atony and postpartum hemorrhage such as placenta previa, multiple gestation, preeclampsia, eclampsia, macrosomia, polyhydramnios, uterine fibroids, previous history of uterine atony and postpartum bleeding, or bleeding diathesis.
* All patients with hepatic, renal, and vascular disease,
* All patients requiring general anesthesia prior to the administration of the study drug.
D: Inclusion Criteria:

1. Non-emergent cesarean delivery with planned spinal anesthesia (i.e. elective planned cesarean delivery for malposition, patient choice, cervical pelvic disproportion, previous cesarean delivery and other diagnosis that require a predetermined cesarean delivery)
2. American Society of Anesthesia physical status class I \& II (ASA I - Healthy, ASA II - mild and controlled systemic disease, eg. controlled essential hypertension)
3. Age ≥ 18 years
4. Term gestational age (≥ 37 weeks)
5. English-speaking

Exclusion Criteria:

1. Morbid Obesity (Body Mass Index ≥ 45 kg/m2) (Morbidly obese parturients require a dose of local anesthetic less than the standardized dose in this study and the blood pressure cuff occasionally needs to be replaced by an intraarterial catheter due to limitations in size)
2. Laboring women
3. Urgent or emergency cesarean delivery
4. Severe hypertensive disease of pregnancy defined as systolic blood pressure (SBP) \> 160mmHg, diastolic blood pressure (DBP) \> 110mmHg and/or requiring antihypertensive treatment or associated with significant proteinuria
5. Severe maternal cardiac disease
6. Subjects predisposed to uterine atony and postpartum hemorrhage (i.e. placenta previa, multiple gestation, macrosomia, polyhydramnios, uterine abnormalities, or bleeding diathesis, \> 2 previous CD)
7. Fetal anomalies /Intrauterine Fetal Demise
8. Failed spinal anesthesia
9. Patient enrollment in another study involving a study medication within 30 days of CD
10. Any other physical or psychiatric condition which may impair their ability to cooperate with study data collection

Answer: D