Reasons for Difficult Labor Health Article

The factors affecting how labor progresses may be divided into types: intrinsic factors arising from the mother and fetus themselves and extrinsic factors from the surrounding environment. The intrinsic factors that cause difficult labor, also referred to as the forces of labor, are defined as:

• Power-the strength of the mother's contractions and pushing efforts;
• Passenger-the general condition of the fetus, as well as its size and presentation; and
• Passage-the size and shape of the pelvis and the tissues it contains.

As one may imagine, some of the forces of labor are fixed and cannot be altered. The power is one factor that can be augmented, when appropriate, with oxytocin. The passenger is fixed in size at the time of delivery, but proper prenatal care and monitoring fetal growth can affect the size of the passenger when labor occurs. In select cases, labor can be induced in order to constrain the size of the passenger, though, the accuracy in predicting delivery weights is still fairly crude and labor induction is generally reserved for other indications. The passage cannot be adjusted.

Extrinsic factors include such things as epidural anesthesia.

For more information on reasons for difficult labor, go to Difficult Labor: Contractions & Pushing, Difficult Labor: Size & Position of Baby, and Difficult Labor: Birth Canal Issues.

Abnormalities of the first stage of labor complicate about 10% of cephalic (head-first) deliveries. Abnormalities of the second stage of labor complicate another 10%.