The study will be designed as a double-blind, placebo-controlled, parallel-group, dose-finding study with one group treated with placebo and three groups treated with tafoxiparin in three different infusion concentration levels, respectively. The intravenous infusion will be initiated by a pre-defined bolus dose infusion.

Primary objective

To assess the dose-response relationship of tafoxiparin on the labor time defined as the time from the start of continuous infusion of tafoxiparin/placebo as an Adjunct Treatment to Oxytocin, until partus in term-pregnant, nulliparous women requiring labor augmentation due to Primary Slow Progress of Labor including prolonged latent phase and Labor Arrest.

Secondary objectives

To assess the safety and efficacy of tafoxiparin based on the safety and secondary efficacy parameters evaluated in the protocol. PK (pharmacokinetic) response in pregnant women during labor.

Methodology

All term-pregnant, nulliparous women presenting to the delivery ward are potential study patients unless they have already been enrolled in another clinical study. Subjects may be pre-informed about the study through the use of advertisements or information at the physician/midwife visits during pregnancy and at hospital admission.

The whole study includes the following steps:

• Screening and Baseline including informed consent and randomization
• Labor
• Discharge
• Follow-up at 8 (+/-1)weeks - End of study
• Safety follow up of infant at 6 months, +/-4 weeks, by telephone interview

Inclusion Criteria:

1. Pregnant women of ≥18 to ≤45 years of age
2. Nulliparous
3. Gestational age > 36 weeks + 6 days confirmed by ultrasound
4. Experience slow progress of labor including prolonged latent phase and labor arrest (according to the respective definitions) etc

Exclusion Criteria:

1. Subjects with secondary slow progress or secondary labor arrest
2. BMI≥35 during first trimester of pregnancy
3. Breech presentation or other abnormal presentations etc