A recent study of the effects of the labor augmentation drug oxytocin has demonstrated that high-dose oxytocin regimens during labor are as safe as low-dose regimens, and can significantly shorten the amount of time women are in labor.
These findings are good news for some mothers and babies. Shorter labor can be an advantage, especially in high-risk pregnancies, because doctors can examine the mother’s reproductive tract and the newborn sooner, and administer care as necessary. It is also thought that shorter labors may reduce the period of time of “intolerable“ pain and thereby reduce the soaring worldwide Caesarean section rates.
The study was conducted by doctors and researchers from Tehran University of Medical Sciences’ Shariati Hospital in Tehran, Iran, and appeared in the October 2004 issue of the International Journal of Gynecology & Obstetrics.
The research study, written by A. Jamal and R. Kalantari, noted that the dosage “level required to produce effective contractions vary widely among individuals,“ depending on how well each patient’s uterus responds to the drug, and factors like whether a patient is giving birth to her first baby or has had a baby before. The ideal dosage of the drug, noted the writers, is one that affects “uterine activity that is sufficient to produce cervical change and fetal descent“ while not over-stimulating the uterus or putting the baby at risk.
Because bias was thought to have played a role in the results of prior studies, the researchers conducted a double-masked, randomized trial, where the doses were randomly assigned to patients, and then prepared by the chief resident of the local obstetrics/gynecology residency program, who did not participate in the monitoring of the patients. The medication was then administered by the residents in the program who did not know what the dose was.
In a group of 200 patients, 100 received high dose oxytocin and 100 received low dose oxytocin. The high dose of oxytocin was three times stronger than the low dose (15 u of oxytocin/500 cm3 for the high dose patients, versus 5 u of oxytocin/500 cm3 for low dose patients). The doses were administered in the same volume, but increased by different increments, with the incremental increase of high dose oxytocin three times the incremental increase of low dose oxytocin (4.5 ìm/min every 30 min versus 1.5 ìm/min every 30 min).
The researchers found that the average time between when doctors started administering the drug and when the babies were delivered was decreased significantly for women who had received the high dose of oxytocin, with women delivering within an average of 4 hours on high dose oxytocin and within an average of 6 hours on low dose oxytocin. Also, abnormalities in fetal heart rates were no more likely with the use of high doses than with low doses.
In non-assisted childbirth, women usually deliver in between 12 and 24 hours, though for some, labor can last for 12 or more hours longer.
SOURCE: International Journal of Gynecology & Obstetrics, October 2004.
Last updated: 21-Oct-04