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ORIGINAL ARTICLE
Year : 2023 | Volume
: 13
| Issue : 1 | Page : 9-16
Effect of age of gravida on post-cesarean section pain: An observational study
Mohammad Kasim1, Deepak Malviya1, Soumya Sankar Nath1, Shilpi Misra1, Suraj Kumar1, Samiksha Parashar1, Neetu Singh2
1 Department of Anaesthesiology and Critical Care, Dr. Ram Manohar Lohia Institute of Medical Sciences, Vibhuti Khand, Gomti Nagar, Lucknow, Uttar Pradesh, India
2 Department of Obstetrics and Gynecology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Vibhuti Khand, Gomti Nagar, Lucknow, Uttar Pradesh, India
Correspondence Address:
Dr. Samiksha Parashar
Department of Anaesthesiology and Critical Care, Dr. Ram Manohar Lohia Institute of Medical Sciences, Vibhuti Khand, Gomti Nagar, Lucknow, Uttar Pradesh – 226 010
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/JOACC.JOACC_11_22
Objective: Preoperative identification of women at greater risk of post-cesarean pain might allow more intensive analgesic interventions. This study aimed to assess the effect of age of a parturient on post-cesarean section (CS) pain. Methods: 100 pregnant females were enrolled and divided into 4 groups: group A (age 18–24 years), group B (25–30 years), group C (31–35 years), and group D (≥36 years). Patient-controlled epidural analgesia was started postoperatively in all patients. Pain on a 0- to 10-point visual analog scale (VAS), a number of attempts tried for patient-activated dose delivery of ropivacaine, and successful delivery of patient-activated dose of ropivacaine were recorded for 72 hours. Breastfeeding was initiated as early as possible. The effect of breastfeeding on post-CS pain was observed for 72 hours in terms of increase, decrease, or no change in VAS scores with breastfeeding. Results: The peak VAS scores over 72 hours were 4.10 ± 0.60, 4.00 ± 0.67, 3.75 ± 0.45, and 3.42 ± 0.67, respectively, in groups A, B, C, and D, showing a significant declining trend (P = 0.007). The mean VAS scores decreased from 4.08 to 1.69 (group A, P < 0.0001), from 4.00 to 1.64 (group B, P < 0.0001), from 3.67 to 1.25 (group C, P < 0.0001), and from 3.33 to 1.50 (group D, P < 0.0001) over 72 hours. A statistically significant decline in patient-activated rescue drug delivery attempts, the number of times the rescue analgesic was delivered, and 24-h cumulative ropivacaine dose requirement was seen. Conclusions: In this study, it was found that post-cesarean pain decreases significantly with increasing age, as evidenced by reduced pain scores, reduced attempts at rescue drug delivery, and reduced rescue analgesic requirements.
Keywords: Acute postoperative pain, breastfeeding, cesarean delivery, maternal age
Cesarean section (CS) is being increasingly used as an option for delivery throughout the world, particularly in low- and middle-income countries.[1],[2],[3] In India, the CS delivery rate increased from 149.33/1000 live births in 2009 to 234.03/1000 live births in 2015.[4] Post-cesarean pain is a significant issue with a high incidence ranging from 77.4%[5] to 100%.[6] Interestingly, postoperative pain is ranked highest among the undesirable clinical outcomes associated with CS.[7] Unlike other surgical procedures, post-cesarean pain should be viewed differently as several hormonal and emotional changes accompany it,[8] thereby increasing the risk of developing chronic pain and postpartum depression, negatively impacting breastfeeding and newborn care,[9] delaying functional recovery, and a more extended hospital stay. Such events increase medical expenses and, thus, are becoming a public health issue.[10]
Despite numerous measures developed to manage postoperative pain, inadequate analgesia after CS is common, with an incidence of nearly 50%.[10] Preoperative identification of women at greater risk might allow for targeting this population with more intensive analgesic interventions. A study of factors influencing post-cesarean pain revealed preoperative anxiety, type of anesthesia,[11] tobacco use,[12] higher body mass index, longer procedure time, single woman, and blood group O[13] as predictors of increased analgesic consumption. None of these studies reported maternal age as an independent predictor of postoperative pain. Given that age plays an essential role in molding the perceptions, it can modulate pain perception and affect post-cesarean pain.
Whereas age has been identified as one of the best predictors of postoperative pain,[14] there is a lack of clinical studies evaluating the role of age of a parturient on post-cesarean pain. Therefore, this study was planned with the aim to assess the effect of age of a parturient on post-CS pain. Our primary objective is to compare the visual analog scale (VAS)[15] scores for post-CS pain among parturients within different age groups. The secondary objective is to study the effect of breastfeeding on post-CS pain.
Materials and MethodsThe Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines were followed and implicated in this prospective observational cohort study.[16],[17] This study was conducted in the Department of Anesthesiology and Critical Care in association with the Department of Obstetrics and Gynecology at a tertiary care center. The study protocol was approved by the institutional ethical committee (IEC no. 68/18, ref.no. 178/RMLIMS/2019, dated April 9, 2019). Before the enrolment of patients, written informed consent was obtained from the patients, and the study was registered on the clinical trials registry—India (CTRI/2021/03/031722). The study spanned a duration of 18 months, starting from May 2019 to November 2020.
Inclusion and exclusion criteria
This study included women aged >18 years, ASA (American Society of Anesthesiologists) physical status I or II with gestational age >37 weeks, and planned to undergo elective CS surgery with a transverse incision. Exclusion criteria were consent refusal, patients with ASA ≥III, any psychiatric or cognitive disorder, patients of pregnancy-induced hypertension or any other comorbidities (diabetes mellitus, hypertension, bronchial asthma, liver or kidney failure, bleeding disorder, neuromuscular disorder, allergy to local anesthetics), inability to understand/operate patient-controlled epidural analgesia (PCEA) pump, and any absolute or relative contraindication to the central neuraxial block.
A detailed history analysis, a complete physical examination, and a thorough preoperative evaluation were performed. Preoperative investigations included complete blood count, coagulation profile, blood urea, serum creatinine, serum sodium, serum potassium, and blood sugar level analyses. In addition, other investigations, as and when necessary, were performed.
All potentially qualified patients were enrolled in this clinical study and were divided into 4 groups based on age: group A (18–24 years), group B (25–30 years), group C (31–35 years), and group D (≥36 years).
Procedure
Patients were kept fasting for 8 hours, and all patients underwent the same anesthetic technique as described below. Then, the patients were taken inside the operation theater. Multipara monitors (cardiac rhythm via electrocardiography, noninvasive blood pressure, and pulse oxygen saturation) were attached. The intravenous line was secured with an 18G cannula. Preloading was done with 500 mL of intravenous Ringer's lactate fluid. Basal vital parameters such as the pulse rate, blood pressure, respiration, and oxygen saturation were recorded.
In this study, the anesthesia technique for cesarean delivery was combined spinal-epidural (CSE) block by needle through the needle technique in a sitting position. Taking all aseptic precautions, CSE was administered at L3–4 or L4–5 intervertebral space. Drugs administered during the procedure were 3 mL of 2% lignocaine infiltration for local anesthesia and 12.5 mg of hyperbaric 0.5% bupivacaine administered into the subarachnoid space. About 4 to 6 cm of an epidural catheter was left in the epidural space. The epidural catheter was well secured and fixed using an adhesive.
After positioning the patient supine, sensory block based on the loss of sensation to pinprick and motor blockade based on Modified Bromage score was noted. After completion of the surgery, the pain was recorded on a 0- to 10-point VAS,[15] where a score of 0 indicated no pain and 10 indicated the worst possible pain. Resting VAS was recorded. The observations were made and recorded by a single observer in all patients. All patients underwent lower-segment CS surgery through a transverse incision along the natural skin fold or along the scar of a previous surgery that was extended depending on the baby's head circumference. Closure of uterotomy was performed with two continuous sutures, and the skin was incision closed with intracutaneous continuous sutures. All surgeries were performed by the same obstetric surgeon.
After completion of the surgery, when the VAS score exceeded 3, 3 mL of 2% lignocaine with adrenaline 1:2,00,000 dilution was given as a test dose through the epidural catheter to exclude intravascular or intrathecal migration of the catheter. Subsequently, the loading dose of 10 mL of 0.2% ropivacaine was given, and this time was taken as T0. The time duration between spinal anesthesia dose (Ti) and epidural bolus dose (T0) was recorded. Continuous infusion of 0.2% ropivacaine was started through a PCEA pump at a background rate of 5 ml h − 1 after bolus dose in all patients for 72 hours. All patients were guided to use the PCEA pump. Patient-activated dose of 3 mL of ropivacaine and lockout interval of 20 minutes was set in the PCEA setting, and patients were allowed to self-administer the additional PCEA boluses. Patients were administered a rescue drug (500 mg of paracetamol intravenously based on the institutional protocol and to avoid opioids) when the VAS score exceeded 3.
Early breastfeeding was recommended as soon as possible after surgery. To ensure early breastfeeding, babies were given to be held by the mothers within 30 minutes of completion of CS. A nurse was available to help the mother with the process of breastfeeding. All women were provided a diary after delivery and were instructed to record their VAS score 5 minutes before and 5 minutes after each breastfeeding.
Data collection
The VAS score was recorded at 6, 12, 18, 24, 48, and 72 hours after the epidural bolus dose (t-0). The number of attempts tried for patient-activated dose (ropivacaine) delivery in 24, 48, and 72 hours and successful delivery of patient-activated dose (ropivacaine) in 24, 48, and 72 hours were recorded. The cumulative dose of ropivacaine and the rescue analgesic (injection paracetamol) was also recorded at 24, 48, and 72 hours from T0. The time of breastfeeding initiation from the end of CS surgery was noted.
A minimal clinically important difference in the VAS score during breastfeeding was assumed to be a change in the VAS score of 2. The changed estimates of VAS scores were averaged to determine the effect of breastfeeding on post-CS pain at 0–6, 6–24, 24–48, and 48–72 hours after T0 in terms of increase, decrease, or no change in pain.
Statistical analysis
The sample size of the study was kept at 100. No prior sample size calculation was done, and the basis of sample size determination was convenience and feasibility. The current study aimed to find the correlation between the VAS score observed for women with cesarean delivery and their age. Because no previous study attempted to determine this correlation, it was decided to include 100 such females in this study. This would serve as a pilot study attempting to correlate the age of a parturient with post-CS pain.
All data were collected and recorded electronically by the same observer. Data were analyzed using Statistical Package for Social Sciences, version 21.0. Chi-square test and analysis of variance (ANOVA), followed by post-hoc analysis (Tukey HSD test) were used to compare the data. A P value less than 0.05 indicated a statistically significant association.
ResultsCharacteristics of the cohort
The participants' flow diagram is shown in the supplementary appendix. Of 111 women screened for eligibility, 103 were deemed eligible. Of these, 3 had to be excluded (2 had accidental removal of the epidural catheter, and in one patient, the epidural catheter had to be removed at 24 hours due to paresthesia), leaving 100 women who completed the 72-h follow-up period. The mean age ± standard deviation (SD) of the patients was 27.62 ± 4.73 years. The anthropometric, demographic, obstetric, and preoperative profiles of all groups are shown in [Table 1]. The body mass index of women ranged from 20.0 to 28.9 kg m − 2. Although the proportion of overweight women was higher in groups C and D as compared to groups A and B, this difference was not significant statistically (P = 0.350). Except for 7.7% of women in group A and 2.7% in group B, all other women were from urban areas. There was no significant difference among groups with respect to the place of residence (P = 0.467). Statistically, there was a significant difference among groups with respect to parity (P = 0.004). The mean time from giving spinal analgesia (Ti) to epidural bolus (T0) was minimum in group A (193.46 ± 14.29 min) and maximum in group D (233.33 ± 12.31 min), thus showing a significant increasing trend with increasing age (P < 0.001).
Table 1: Comparison of anthropometric, demographic, obstetric, and preoperative profiles of women in different age groupsVAS score
[Table 2] shows the comparison of VAS scores at different postoperative follow-up intervals. The data were normally distributed. During the entire follow-up period, the peak VAS scores were 4.10 ± 0.60, 4.00 ± 0.67, 3.75 ± 0.45, and 3.42 ± 0.67, respectively, in groups A, B, C, and D, showing a significant declining trend (P = 0.007). The post-hoc comparison revealed that the mean peak pain scores were significantly higher in groups A and B as compared to that in group D. A significant difference in mean VAS scores for pain among women in different age groups was observed at 6 h (P = 0.003) and 24 h (P = 0.009) postoperative intervals, indicating a higher intensity of post-cesarean pain in younger age groups during the first 6 hours following surgery.
Table 2: Comparison of VAS scores at different postoperative follow-up intervalsRescue analgesic requirement
The number of patient-activated drug delivery attempts, the number of successful drug delivery events, 24-h cumulative ropivacaine requirement, and mean paracetamol use among different groups are shown in [Table 3]. A statistically significant declining trend was seen with increasing age during 24 and 48 hours in the number of patient-activated drug delivery attempts (P < 0.001 and P = 0.004, respectively) and the number of times the patient-activated analgesic was delivered (P < 0.001 and P = 0.007, respectively) through a PCEA pump. However, beyond that time period, there was no significant intergroup difference in both patient-activated drug delivery attempts and the number of times delivered (P = 0.207 and P = 0.166, respectively). The post-hoc evaluation revealed that group A had a significantly higher number of attempts and a higher number of drug delivery events than all the other groups (P < 0.05).
Table 3: Evaluation of number of patient-activated drug delivery attempts, number of successful drug delivery events, 24-h cumulative ropivacaine requirement, and mean paracetamol use among different groupsTwenty-four-hour cumulative ropivacaine requirement for the first 24 and 24–48 hours was maximum in group A compared to other groups with a statistically significant intergroup difference. Post-hoc evaluation using Tukey HSD revealed that for the first 24 hours, group A had significantly higher ropivacaine requirement as compared to all other groups (P < 0.05), and group B had significantly higher ropivacaine requirement as compared to group D. None of the other between-group differences were significant statistically (P > 0.05). For 24–48 hours, on post-hoc evaluation, only the difference between groups A and D was found to be significant (P = 0.038). Statistically, no significant intergroup difference was seen for 48–72 h.
Statistically, a significant difference was found (P = 0.002) among different groups for the need for total rescue analgesia (injection paracetamol) during the first 24 h. On post-hoc evaluation, it was found that group D had significantly lower requirements than all other three groups (P < 0.05). The intergroup difference was insignificant beyond 24 hours. This shows a decremental trend in the need for rescue analgesia with increasing age.
Breastfeeding
[Table 4] indicates the pattern of pain after breastfeeding in different groups at different time intervals. One mother and one newborn were shifted to the intensive care unit (ICU), and in another, breastfeeding could be initiated after 24 hours, and hence, they were excluded. The time taken to start the feeding ranged from 30 to 175 minutes. The meantime of the start of breastfeeding in group A (60.14 ± 31.28 min) and group D (56.67 ± 27.16 min) was higher as compared to that in group B (52.78 ± 20.58 min) and group C (51.67 ± 6.78 min), but this difference was not significant statistically (P = 0.619). Thus, breastfeeding was initiated as early as possible as an advantage of the central neuraxial block. A significant intergroup difference (P = 0.016) was observed only at 0–6 hours, where the proportion of those patients showing an increase in VAS scores with breastfeeding was significantly higher in groups A and B compared to that in groups C and D. After 6 hours, the proportion of patients showing a decrease in VAS scores with breastfeeding increased in all groups. There were no significant intergroup differences in the pain pattern after 6 hours.
Table 4: Pattern of pain after breastfeeding in different groups at different time intervals Discussion This is a pilot study, and we intended to focus primarily on the age of a parturient as a determinant after excluding other possible factors which could influence the postoperative pain experience. Our study found that the mean time from giving spinal analgesia to epidural bolus showed an increasing trend with increasing age, and the mean VAS scores showed a declining trend with advancing age at all time intervals.
Experiments in animal studies have revealed that the response to nociceptive stimuli depends on age and chronicity of pain.[18],[19] This response toward subsequent pain often diminishes with prior exposure to pain.[20] In this manner, the age of a parturient becomes an important factor that could influence post-cesarean pain. However, the association between age and postoperative pain is complex and has not shown a consistent effect in different studies.[21],[22] Preterm and emergency CS were excluded from this study. They may act as confounding factors because they are associated with higher complication rates, which might influence the degree and severity of postoperative pain.[23] Similarly, women with other comorbid conditions (such as hypertension and diabetes) and those from psychiatric or cognitive disorders were also excluded owing to their variable effect on pain. Women with higher ASA grades were also excluded for a similar reason.
A significant difference in mean VAS scores for pain among women was observed at 6- and 24-h postoperative intervals. Peak VAS scores were higher in the younger age group. Compared to our study, Jasim et al.[13] showed the peak VAS pain score to be only 1.02 ± 0.70 observed by them at a 12-h postoperative interval. They reported mean pain scores among women >31 years to be significantly higher (0.23 ± 0.68) compared to those in women aged <31 years (0.16 ± 0.51). The pain scores reported by them are much lower than those reported elsewhere in the literature. Kashanian et al.[24] reported mean pain scores to be 7.28 ± 0.22, 5.85 ± 0.15, 4.33 ± 0.18, and 2.71 ± 0.13, at 4-, 8-, 12-, and 24-h intervals, respectively, in the low-progesterone group and 6.00 ± 0.20, 4.42 ± 0.11, 3.18 ± 0.15, and 1.16 ± 0.09, respectively, at the corresponding time intervals in the high-progesterone group of their study; however, they did not assess the role of age on the postoperative pain. Mehdiratta et al.[12], however, reported the pain intensity in terms of mild (pain scores 1–3), moderate (pain scores 4–6), and severe (pain scores >7) pain in 47.2%, 47.1%, and 5.7% women, respectively, and similar to the present study, they also found a significant association of increasing age with decreasing pain scores. Borges et al.[11] also reported mild (VAS 1–4), moderate (VAS 5–6), and severe pain (VAS 7–10) in 15.2%, 32.6%, and 52.2% of women, respectively, but did not find a significant association of severe pain with age. However, it would be pertinent to mention here that in their study, the mean age of women was only 25.1 years, and as such, there were fewer women aged >30 years. Moreover, they included women aged as young as 14 years and both elective and emergency CS and did not have strict inclusion criteria as used in our study.
When the results related to analgesic use patterns were analyzed, the number of attempts, successful drug delivery events, cumulative ropivacaine dose, and oral paracetamol dose use were more pronounced in the youngest age group (<25 years) compared with other age groups. These findings imply that not only pain perception but also attempts to resolve them and the analgesic need were significantly reduced in the women aged more than 35 years. As such, increasing age within the reproductive age group has been reported to influence the hormonal environment of women, which could be the underlying reason for increased tolerability and decreased perception of painful stimuli.[25],[26]
In this study, we found a significant association of multiparity with increasing age [Table 1]. Older women with an experience of previous labor pain are psychologically well prepared to encounter a similar episode in the future. Hence, their readiness and acceptance of painful stimuli are more favorable compared to the younger women, resulting in relatively lower pain scores compared to their younger counterparts. Multiparity has been reported to have a protective effect against post-CS pain in a number of previous studies too.[12],[27],[28]
We observed that during the initial 6 hours of breastfeeding, younger women showed an increase in pain, whereas older women showed a decrease in pain during breastfeeding. However, after that period, the majority of women in all age groups showed no change or decrease in pain while breastfeeding. It is believed that endogenous oxytocin release during breastfeeding might have a modulatory role in affecting the pain perceptions. However, Wen et al.[29] failed to find a significant association between post-CS pain and breastfeeding. In fact, the authors found that breastfeeding increased cramping pain. As such, breastfeeding following CS is affected by interrelated and compounding difficulties.[30] For the younger women, these difficulties are first-hand experience, whereas older-age-group females had their own or acquired experience of such difficulties owing to which they readily accept breastfeeding as a pleasing change that helps them to eliminate pain. The trends in this study showed that repetition of the process of breastfeeding in younger women helped them to experience a decrease in pain with the passage of time. As such, a decrease in pain following breastfeeding might be influenced by a number of other factors such as skin-to-skin contact, psychological satisfaction derived from breastfeeding, and diversion of attention from pain to breastfeeding.
The present study has certain limitations. Firstly, the small sample size requires further studies to clearly delineate the effect of age on post-cesarean pain. Secondly, to reduce the biases such as surgical method, operation time, and anesthetic method, we collected data from a single operation theater of a single center. Also, all patients were operated on by the same obstetric surgeon. These factors can affect the generalization of our results. Thirdly, we found a significant intergroup difference in the parity of women. The findings of our study showed that younger women had higher pain scores, which were significant in the early postoperative period only. This observation could be attributed to low parity and lack of experience of labor pain. It was not possible to match and adjust the parity of pregnant women in various age groups. A detailed obstetric history with details regarding previous modes of delivery could have helped in assessing the experience of previous cesarean delivery in modulating pain perceptions. Fourthly, in an attempt to include healthy parturients, we excluded women with various comorbidities. Females with known hypertension and diabetes were excluded to void the altered pain sensitivity that may be associated with hypertension and diabetes. This could affect the external validity of our study. To understand the effect of age on various maternal profiles and also to delineate the physiological mechanisms responsible for such age-related differences, various comorbid profiles should have been included. Moreover, a psychological assessment of mothers could also have helped to elucidate the role of psychological factors and their relatedness with the changing age profile of women and, in turn, their effect on pain. Despite these limitations, this study for the first time evaluated and was successful in highlighting the role of maternal age on post-CS pain. However, further studies tackling these limitations on larger sample sizes are recommended to find good-quality evidence.
ConclusionIn summary, we found that post-cesarean pain decreases significantly with increasing age, as evidenced by decreasing pain scores and reduced requirement for rescue analgesics after surgery. Therefore, our findings indicate that the age of a parturient and early breastfeeding does affect the postoperative pain severity. Hence, clinicians may consider these factors and psychological or physiological support for the mother during the antenatal period to reduce postoperative pain and its related complications.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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