EXPANSION OF UTERINE INCISION AT CAESAREAN SECTION, AND MATERNAL BLOOD LOSS

INTRODUCTION

Maternal mortality rate in Pakistan is 281- 433 per 100,000 live births.¹ The leading cause of this high mortality rate is obstetrical blood loss.² Recently there has been an increase in the number of caesarean sections that amounts to 25% of all deliveries in most of the institutions. Although caesarean section delivery is much safer today due to improved techniques, but still it is a major cause of intraoperative and postoperative complications. Its morbidity remains high as compared to vaginal deliveries. Any blood loss greater then 1500 ml or a fall in hematocrit greater than 10 % (American College of Obstetrics and Gynaecology³) requires blood transfusion.

Several surgical techniques have been developed to reduce intraoperative blood loss during caesarean section deliveries. One of these techniques that remain debatable is expansion of uterine incision, either by sharp or blunt methods. Different surgeons based on their own experiences have advocated each method. Very few prospective studies have demonstrated any merits or demerits associated with either of these methods.

The present study highlights the technique of extending of uterine incision that is associated with less intra-operative blood loss and complications.

MATERIAL AND METHODS

All the patients reporting for elective caesarean section from May 2002 to April 2003 were included in the study. Nearly half of these patients were assigned to group I (in these patients uterine extension was made by sharp incision). The other half of patients were designated to group II (in which uterine extension was made bluntly (digital maneuver). Distribution of patients to either group was made on the basis of non- randomized (convenience) sampling. Inclusion criteria comprised of all primigravida / multigravida, singleton pregnancy, gestational age 37- 47 weeks, BMI (body mass index) < 30, primary and repeat low segment caesarean section. Similar anaesthetic techniques were administered to all patients. Indications for caesarean section included fetal distress, failed progress of labour, unstable lie, cephalopelvic disproportion, malpresentation, repeat caesarean section and pre-eclamptic toxemia. All patients with multiple pregnancies, polyhydramnios, ante partum hemorrhage, previous history of postpartum hemorrhage (PPH) and uterine fibroids were excluded from the study. Blood hemoglobin, hematocrit, blood grouping and Rh factor were performed in all patients. Pre-operative preparations and technique were same in both the patient groups, except the procedure for expanding the uterine incision. Pre-operative antibiotics (Augmentin 1.2 Gm IV) were given 30 minutes before induction of anaesthesia. A Pfannensteil skin incision was made followed by low transverse uterine incision. After making an incision of 2 cm in the uterine wall with a scalpel, the incision was extended either by sharp or blunt methods. After delivery of the fetus, placenta was delivered by controlled cord traction. Syntocinon (10 Units IV) was given alongside. Uterine closure was done in two layers. Trained second and third year residents, under supervision of the consultant, performed all surgical procedures. Measuring the amount of blood in the suction apparatus and weighing the pre-weighed sponges estimated intra-operative blood loss and patient drapes. Hematocrit was repeated after 48 hours of operation. A record of blood transfusions was kept along with the number and extent of tears. An extension or tear was defined as inadvertent extension of uterine incision beyond normal limits. All data pertaining to the age of patients, parity, gestational age, and body mass index (BMI), indication for surgery, primary or repeat caesarean section delivery and birth weight of the baby were recorded in a proforma and a comparison was made (Table 1).

RESULTS

Group I consisted of 98 patients while group II comprised of 100 patients. Both groups were compared for their demographic characteristics and clinical data i.e. maternal age, parity, gestational age, BMI, indication for caesarean section, stage of labour and birth weight of newborn (Table 1). No significant difference was found amongst the two groups. Outcome measurements for both groups regarding blood loss, number of blood transfusions and unintentional uterine tears were compared (Table 2). The mean age of patients in both the groups was similar, along with parity, gestational age, stage of labour, preoperative hematocrit. Predisposing factors, which may affect blood loss during surgery like pre-eclamptic toxemia and type of anesthesia⁴, were also similar in both patient groups. Blunt group contained less repeat caesarean (28/100) than the sharp group (33/98). There was no significant difference in birth weights of newborns in both groups of patients. The mean pre-operative hematocrit too was similar. Intra- operative blood loss was more in ones with blunt incisions (range=240ml—1600ml) than the sharp group (range=300ml—1450ml)(p< .01). Rate of blood transfusions between blunt group and sharp group was 2:1(p< .001). The post-operative drop in hematocrit was greater in those with blunt incisions (p < .01). None of the patients with sharp incisions sustained inadvertent extension of incisions, whereas there were seven such cases in those with blunt incisions, four involved the cervix and three extended into the broad ligament (p< .007). All these patients who sustained tears received blood transfusions. The development of tears possibly resulted in a greater blood loss in these patients.

Table-1:Comparison between sharp and blunt group

Character

Sharp group

N=98

Blunt group

N=100

Mean Age

28.4 ± 5.13

27.1±5.35

Parity

Nulliparous

Multiparous

Mean Gestational age

38.43

wks±1.26

38.44

wks±1.22

Indication for Cesarean

*Arrest of Labour

*Breech

*CPD

*FD

*Previous Cesarean

*PET

*Unstable lie

BMI Mean

26.64±1.61

27.16±1.43

Stage of Labour

Type of Anesthesia

General

Spinal

Preoperative Hct

Mean

33.64±2.1

33.51±2.5

Birth Weight

Mean

3.47

Kgs± .259

3.39

Kgs±. .250

Table 2.Comparison of the outcome of the two groups.

Variable

Sharp

Blunt

P value

Tears

Cervical

Lateral

Vaginal

Nil

.007

Blood Loss

Mean

744.38 ml

829.60 ml

.01

Fall of Hematocrit

Mean

2.57±1.3

2.86±0.4

.01

Blood Transfusion

11 pint

22 pint

.001

DISCUSSION

In early days caesarean sections were carried out by vertical midline incisions, which were left open. This led to a high maternal mortality due to haemorrhage. Surgical techniques to perform caesarean sections have evolved over the passage of time.⁵ In 1926 Kerr introduced the most popular approach of low transverse incision in the uterine wall, which is the one being used by the majority of surgeons today. Advances in anaesthesia, surgical techniques, suture materials, antibiotics and blood transfusion practices have made caesarean section a fairly safe procedure. The overall complication rate of caesarean section is 11.6% although this rate is much higher for emergency caesarean section (14.5%) then for elective CS (6.8%).⁶ Intra-operative hemorrhage is one of the most important and a leading cause of caesarean section associated morbidity and mortality.¹ A variety of surgical techniques have been employed to restrict blood loss during caesarean section. These include spontaneous versus manual delivery of placenta,⁷ in situ repair of uterine incision versus uterine exteriorization,⁷ T and J extension in low transverse births,⁸ and comparison of modified Joel – Cohen technique for caesarean section with Pfannensteil technique,⁹ blunt versus sharp expansion of uterine incisions in low transverse caesarean section.^{10, 11} This technique of expansion of uterine incision by sharp versus blunt method has been evaluated in this study. Various obstetricians based on personal experience and preference has used both techniques. The blunt method involves introduction of fore fingers into the initial uterine incision, followed by forcefully splitting the uterine musculature laterally and superiorly.¹² The main theoretical advantages of this technique are decreased blood loss and reduced operating time. The force required to expand the incision cannot be calculated or controlled and therefore may result in unintended extension of incision into the broad ligament damage the major vessels. Such inadvertent tears may involve the cervix or vagina. In sharp method, using bandaged scissors expands the incision and the extension is therefore controlled and precise. The main disadvantage of this method may be increased blood loss due to severed blood vessels in myometrium¹² and fetal laceration injuries.¹³ In 1994 Rodriguez et al were the first to compare these two methods in a study conducted at Tampa General Hospital, Florida from 1^st September 1992 to 30^th June 1993.¹⁰ Both methods were found to be interchangeable, as there was no significant difference between the two techniques regarding amount of blood loss and uterine tears. Although blood loss was more in sharp group and uterine tears were more in blunt group, but the difference was statistically insignificant. Between June 1998 and June 2000, Magann et al conducted a comparative study between these two techniques.¹¹They found that blood loss and uterine scar extension were significantly more in sharp group then the blunt group. It was thus concluded in the study that blunt method of expansion of uterine incision is superior to sharp method in respect of blood loss and inadvertent uterine tears. In our study we were unable to find any such outcome. According to the statistical analysis of our study, there was more blood loss and uterine tears in blunt group than in the sharp group. Unintentional tear formation in the blunt group probably resulted in increased hemorrhage. All those patients who developed uterine tears had a blood loss above 1380 ml and a fall in hematocrit greater than 10 points, thus necessitating blood transfusion.

CONCLUSION

Sharp method of expansion of uterine incision in caesarean deliveries is more precise, accurate and results in less blood loss and inadvertent tear formation when compared with blunt method.

References

1. Fikree FF, Midhet F, Sadruddin S, Berendes HW. Maternal mortality in different Pakistani sites: ratios, clinical causes and determinants. Acta Obstet Gynecol Scand 1997; 76(7): 637-45

2. Jafarey SN. Maternal mortality in Pakistan--compilation of available data. J Pak Med Assoc 2002; 52(12): 539-44

3. ACOG educational bulletin. Postpartum hemorrhage. Number 243, January 1998(replaces No. 143, July 1990). American College of Obstetricians and Gynecologists. Int J Gynaecol Obstet. 1998;61(1):79-86.

4. Naef RW 3rd, Chauhan SP, Chevalier SP, Roberts WE, Meydrech EF, Morrison JC. Prediction of hemorrhage at cesarean delivery. Obstet Gynecol 1994;83(6):923-6

5. Field CS. Surgical techniques for cesarean section. Obstet Gynecol Clin North Am 1988; 15(4): 657-72

6. Bergholt T, Stenderup JK, Vedsted-Jakobsen A, Helm P, Lenstrup C. Intra-operative surgical complication during cesarean section: an observational study of the incidence and risk factors. Acta Obstet Gynecol Scand 2003;82(3): 251-6

7. Magann EF, Washburne JF, Harris RL, Bass JD, Duff WP, Morrison JC. Infectious morbidity, operative blood loss, and length of the operative procedure after cesarean delivery by method of placental removal and site of uterine repair. J Am Coll Surg 1995;181(6): 517-20

8. Boyle JG, Gabbe SG. T and J vertical extensions in low transverse cesarean births. Obstet Gynecol 1996; 87(2): 238-43

9. Wallin G, Fall O. Modified Joel-Cohen technique for caesarean delivery. Br J Obstet Gynaecol 1999;106(3): 221-6

10. Rodriguez AI, Porter KB, O'Brien WF. Blunt versus sharp expansion of the uterine incision in low-segment transverse caesarean section. AM J Obstet Gynecol 1994;171:1022-5

11. Magann EF, Chauhan SP, Bufkin L, Field K, Roberts WE, Martin JN Jr. Intra-operative haemorrhage by blunt versus sharp expansion of the uterine incision at caesarean delivery: a randomized clinical trial. BJOG 2002;109(4):448-52

12. Jovanovic R. Incisions of the pregnant uterus and delivery of low-birth weight infants. Am J Obstet Gynecol 1985;152(8): 971-4

13. Smith JF, Hernandez C, Wax JR. Fetal laceration injury at cesarean delivery. BJOG 2002;109(4):448-52.