Evaluation of two methods employed for cervical ripening.KK Damania, U Natu, PN Mhatre, M Mataliya, AC Mehta, SN Daftary
Dept of Gynecology & Obstetrics, Nowrosjee Wadia Maternity Hospital, Parel, Bombay, India., India
The study evaluates breast stimulation and oxytocin infusion as methods for cervical ripening in patients where an obstetric indication for induction of labour exists. Forty patients with a Bishop score of 5 or 6 were randomly selected for either breast stimulation or oxytocin infusion. In a similar group of 20 cases, no method was employed. The Bishop score improved in 41.2% of cases where breast stimulation was used as compared to 75% where an oxytocin infusion was given. Three foetal deaths in the breast stimulation group brought the study to a stop after 17 cases. Cervical ripening with an oxytocin infusion drip appears to be a better method since infusion dosage can be precisely controlled making the technique more predictable and reliable. Though breast stimulation is effective in ripening the cervix, it may be used only in cases of intrauterine foetal death as it may otherwise adversely affect foetal outcome.
Keywords: Breast, physiology,Cervix Uteri, drug effects,physiology,Female, Fetal Death, etiology,Human, Infusions, Intravenous, Labor, Induced, methods,standards,Oxytocin, administration &dosage,therapeutic use,Physical Stimulation, Pregnancy, Pregnancy Outcome,
Induction of labour is often indicated when the benefits of delivery outweigh a continued intrauterine existence.
The success of any induction depends on the state of the cervix. With a dilated, soft, midposed cervix, the chances of a successful induction are high, as compared to the one, which is long, tubular and posterior. Therefore, various techniques to ripen these unripe cervices have been tried over the years.
Prostaglandins have been claimed to be the most successful of methods available for ripening the cervix. However, prostaglandin jellies or pessaries are not available in our country. Elliott and Flaherty and later Salmon et al, published studies advocating breast stimulation for ripening. Damania et al too, reevaluated this technique and found the method effective. Infact, 36% of patients were in labour within 3 days and most of the Bishop scores showed a 3 to 4 point increase. However, all these studies were conducted in a group of patients who did not really require a ripening, without standardized selection criteria and were not compared with other methods.
Hence, in this study a high risk group in whom ripening of the cervix was indicated was included. The patient selection was standardized before allocation to any of the three groups. Two different modalities for ripening of the cervix were compared with a control group in whom no ripening was done.
Primigravidae having completed 37 weeks of gestation and having a Bishop score of 5 or 6 were selected. All patients had to have a reactive nonstress test. The indications for cervical ripening are shown in [Table - 1].
The patients were divided into 3 groups (of 20 each) as follows:
Group 1: Breast stimulation was performed for one hour three times a day gently around the nipple, each breast alternating every 10 minutes. The patient had to be well motivated for the same.
Group 2: Oxytocin infusion started at 2.5 m JU/mi per minute for 3 hours a day, repeated for 3 hours every day for 3 days.
Group 3: Control group. No method was employed.
The Bishop score was re-evaluated at 24 hours and then at 72 hours. The neonatal outcome and nipple problems if any were noted.
Patient distribution pattern in 3 groups is shown in Table 1. Group 1 consisted of only 17 patients as against the allotted twenty. [Table - 2] shows that in Group 1 and Group 2, the scores improved. In fact, 41.2% and 75% of patients in these two groups respectively were in labour by 72 hours.
The neonatal outcome is shown in [Table - 3]. There were foetal deaths in the breast stimulation group and this brought the study to an abrupt end with only 17 patients in the said group. A post mortem examination one on one of these babies revealed no anomalies.
Ripening of the cervix is not all that easy. Earlier articles,, have recommended breast stimulation as preferred method, being simple and convenient. Although these studies had been conducted in cases with no risk factors, many obstetricians have started using breast stimulation even in high risk patients.
It is not clear as to the actual mechanism by which breast stimulation works, but what is definitely known is that it causes uterine contractions. In fact, Huddleston et al recommend doing a contraction stress test (CSI) with breast stimulation. Utilizing breast stimulation to ripen the cervix is like doing a CST three times a day for one hour without the benefit of a foetal monitor. It is like starting an induction of labour where the dose is not known, cannot be controlled and definitely not monitored. This makes breast stimulation unsuitable for use in patients where an obstetric reason for ripening or induction exists. In these cases, it would be best to start an oxytocin infusion and wait 10-12 hours for good uterine contractility, with a doctor monitoring the well being of the mother and the foetus. This definitely is more precise, predictable and a reliable method.
However, it is certain that breast stimulation works and may be used in cases of intrauterine foetal death or if a patient overdates by a few days with no risk factor or in private practice to perform an elective induction for the obstetrician's convenience -the reason which may exist even today.
[Table - 1], [Table - 2], [Table - 3]