Effect Of Amniotomy In Early Labour On Duration Of Labour

Effect of Amniotomy in Early Labour on Duration of Labour in Primigravida at Term Pregnancy: A Randomized Controlled Trial.

Introduction Labor is a physiological but painful experience for women. It is a dynamic and ongoing process that culminates with the delivery of a healthy baby, followed by the ejection of the placenta and membranes.After active labor has begun, the membranes burst, which is known as spontaneous membrane rupture.Amniotomy is the artificial breach of the amniotic membrane with the primary goal of accelerating contraction and shortening the duration of labor.Studies have shown that amniotomy procedure is very effective to reduce the time duration of labour and maternal risk factors. Amniotomy method is also applied when internal monitoring of fetus is required.

The mechanism of action behind amniotomy is thought to be the release of prostaglandin E2 (PGE2) and rise of oxytocin level.Routine early amniotomy appears to be associated with both benefits and risks. It's typically used to accelerate labour and was originally thought to decrease caesarean section rates. Amniotomy is a frequent and low-cost method of inducing labor. The link between early amniotomy and severe maternal morbidity varied according to maternal factors, while early amniotomy was not linked to newborn morbidity.

The current study has been planned to examine the effect of amniotomy in terms of reducing the time duration of labour in primigravida at term gestation. The study results obtained from our local setting will be useful for expertise while selecting the mode of delivery. Evidence-based guidelines will help in practicing standardize care, reduce variability in practice, reduce maternal and neonatal mortality and improve overall outcomes for mothers and babies.

Objective: To compare mean duration of labor in amniotomy compared to spontaneous rupture of membrane in primigravida at term pregnancy.

Operational definitions

Duration of labour: Time (hours) during active labour encompassing 1st and 2nd stage of labour will be noted using a stopwatch by nurse on duty. 1st stage will be labelled from cervical dilatation of 3-4 cm in active labor to full dilatation of cervix (≈ 10 cm) by vaginal examination conducted every 2 hours. The 2nd stage of labour will consist of a phase of active labour from full dilatation to delivery.

Body mass index (BMI): BMI will be calculated by formula- weight in kg/height in meter2. Weight will be measured on a weighing scale and height on stadiometer.

Hypothesis: Mean duration of labour is lower in amniotomy group compared to spontaneous rupture of membrane.

Material & methods

Setting: Department of OBG, Recep Tayyip Erdoğan Hospital, Muzaffargarh

Study design: Randomized Controlled Trial

Duration: 6-months after approval of synopsis

Sample size10: Sample size is calculated through OpenEpi software using formula for mean difference. Where,

Labour duration in amniotomy group = 5.725±0.59 hours Power of the study = 80%

Labour duration in spontaneous membrane rupture = 7.150±0.48 hours

Confidence level = 95% Sample size = 60 (30 in each group)

Sampling technique: Non-probability consecutive sampling

Data collection procedure

Prior approval will be sought from the ethics review committee. A total of 60 women in labour room with active labour, fulfilling the inclusion criteria, will be enrolled with volountry participation after informed consent and confidentiality will be maintained. Baseline characteristics including age, body mass index and gestational age (by LMP method) will be recorded from all the participants. The participants will be randomly assigned to group A and B through lottery method using sealed opaque envelopes.

In group A, amniotomy at 3cm will be done using aseptic measurements with the help of

Kocher's forceps while in group B, membranes will be left intact. A partograph will be maintained in all patients throughout labor. Duration of each stage of labour will be monitored as per operational definition by the nurse not aware of treatment given. Fetal and maternal monitoring will be done half hourly till delivery of infant. Cesarean-section will be done in non-reactive CTG patients. In case of any of the adverse events related to intervention like placental abruption and cord prolapse [that is less likely as the subjects are primigravida patients in which head is mostly already engaged before onset of labour], and presence of meconium upon ARM that is not related to intervention individualized care will be provided like continuous electronic fetal monitoring and emergency caserean section will be kept in hand. If any adverse event occur related to intervention it will be reported to IRB within 24hours. All the patients will be kept under observation for 24 hours after delivery. All the data will be recorded on proforma

Data analysis The data will be analysed through SPSS version 23. The normality of numerical data will be assessed through the Shapiro-Wilk test. Age, BMI, gestational age and duration of labour will be presented as mean and standard deviation. Duration of labour will be compared between group A and group B through independent sample t-test and p-value ≤ 0.05 will be taken as significant. The data will be stratified on age groups, gestational age and BMI categories to determine the effect on duration of labour between group A and B. Post-stratification independent sample t-test will be applied and p-value ≤ 0.05 will be taken as significant.

Inclusion criteria

• Age 18 - 45 years
• Primigravida, singleton fetus (on antenatal scan)
• Full term - gestational age 37 - 41 weeks
• Established labour (presence of regular uterine contractions - 3 per 10 minutes)

Exclusion criteria

• History of chronic hypertension, diabetes mellitus, gestational diabetes - on medical record
• Rupture of the membrane (pooling of fluid in vaginal on speculum examination)
• History of antepartum hemorrhage (history and medical record)