Placenta previa is an obstetric condition characterized by abnormal implantation of the placenta into the lower uterine segment ^[1]. Placenta previa complicates 0.3–0.5% of all pregnancies with incidence of 1 in 300-400 deliveries and is a major cause of third-trimester haemorrhage^[2]. Almost 30% maternal deaths in the Asian population are due to major obstetrical hemorrhage out of which placenta previa is the major cause^[3] .

Placenta previa is classified as: Placenta previa: the internal os is covered partially or completely by placenta, and Low lying placenta : the placental edge does not reach the internal os and remains outside a 2 cm wide perimeter around the os^[4] .

Risk factors of major concern for placenta previa are maternal age, parity, previous caesarean section, previous history of placenta previa, abortions, cigarette smoking, multifetal pregnancies ,infections , trauma , dilatation and curettage, previous uterine surgeries like myomectomy (especially where the cavity is opened), metroplasties etc[5] .

The classical features in placenta previa are sudden onset, causeless, recurrent painless bleeding^{[10] .}Maternal complications of placenta previa are antepartum haemorrhage, maternal anaemia, shock, operative interventions like caesarean section and hysterectomy. Fetal complications includes intrauterine growth restriction, malpresentation, unengaged or floating head at term, preterm delivery, birth asphyxia, increased NICU admissions, intrauterine death and stillbirth ^[6,7,8,9].

Management of placenta previa depends on presentation, gestational age and degree of placenta previa ^[11]. When mothers life is not at risk, expectant management will improve the outcome^[12]. Multidisciplinary multidepartmental management reduces maternal and fetal morbidity and mortality.

Patients presenting with abnormal placental attachment have a complicated surgical course and a high mortality rate. Anaesthetists should be prepared to manage massive blood loss by using effective teamwork, leadership, and communication strategies. Technical skills are paramount to reaching the goal of a positive outcome for mother and baby. The obstetrician and the obstetric anaesthesiologist must know,on-the-spot, how to deal with this problem.

The increased incidence of placenta previa and adherent placenta following prior caesarean delivery is of real concern. The incidence of hysterectomies in such cases are very high. So, in this study, we want to help identify those women with high risk factors during the antenatal period for early diagnosis, timely intervention and prompt management to reduce maternal and fetal morbidity and mortality.

This prospective observational study was conducted among patients attending OPD/IPD in the department of Obstetrics and Gynecology Department Vani Vilas attached to Bangalore Medical College and Research Institute, from February 2021 to August 2022 were included in the study.

Sampling technique: Computer generated simple random sampling numbers.

Sample Size Calculation:

According to the previous study conducted by Mansi et al, 66% had a scarred uterus among the studied placenta previa patients.

The sample size calculation is to be done using the formula:

N =                  Z ²      p (100 - p)

d2

Substituting the above values, the sample size is calculated as, N = 90 However, taking into consideration an attrition or non response rate of 10%, the sample size was calculated as 100

 Inclusion Criteria:

1. Patients who give consent to participate in the

2. All pregnant women diagnosed with placenta previa beyond 28 weeks of gestation at or after admission are included in the study.

Exclusion Criteria:

1. Patients not willing to participate in the

2. Gestational age < 28 weeks.

3. Other causes of antepartum

4. Multiple

5. Pregnant women with hypertension, gestational diabetes and other

6. Comorbid

After obtaining approval and clearance from the institutional ethics committee, the patients fulfilling the inclusion criteria were enrolled for the study after obtaining informed consent. (Annexure – 1). Gestational age was calculated using LMP and EDD as per the earliest first trimester scan. Diagnosis was confirmed by transabdominal and transvaginal ultrasound as and when required. MRI was done to rule out adherent placenta. The cases were divided into two groups:

1. Unscarred uterus- including cases with placenta previa who have no previous history of cesarean section or any uterine surgery like curettage.
2. Scarred uterus - including cases with placenta previa who have a history of 1 or more previous cesarean section or uterine surgery like myomectomy or uterine rupture

Both the groups were compared for parameters such as maternal age, parity, previous obstetric history, mode of delivery, type and grading of placenta, maternal morbidity indicators such as post-partum hemorrhage, need for blood transfusions , need for ICU admission, need for caesarean sections and other extra surgical maneuvers to control excessive bleed, maternal mortality, fetal parameters such as fetal malpresentations, fetal morbidity parameters like prematurity, low birth weight and need for ICU admission as well as mortality parameters such as still births and neonatal mortality rates. All the required information was collected in pre- structured and pretested proforma to fulfill objectives of study.

STATISTICAL-ANALYSIS:

The data was entered into MS Office Excel and analysed using SPSS version 20.0 Sociodemographic data was presented using descriptive statistics namely mean, median, standard deviation , percentage wherever applicable. The CHI SQUARE TEST or T TEST was used to compare the data as appropriate. P value of <0.05 was considered significant. Data is presented in the form of tables, figures and graphs wherever necessary.

Total of 21767 deliveries done in 2years. And a total of 190 cases of placenta previa, among whom, 88 patients had scarred uterus and 102 had unscarred uterus. Incidence of placenta previa in our tertiary care hospital was 0.876%. Incidence of placenta previa in the scarred uterus group was 1.32% and in unscarred uterus group, incidence was 0.67%. Mean age of participants with scarred uterus was 27.74 years and among unscarred uterus, it was 26.12 years.

Table 1: Incidence of scarred and unscarred uterus

Among patients with scarred uterus, 78.75% were booked pregnancies and 21.25% were unbooked. Among patients with unscarred uterus, 78% were booked pregnancies and 22% were unbooked. Prior antenatal records of patients were assessed. A pregnant woman is said to be booked if she attended atleast four antenatal clinic visits, received atleast 1 dose of tetanus immunization and was administered atleast 100 IFA tablets during her pregnancy.

Prior USG diagnosis of placenta previa was done among 64.1% patients with scarred uterus and in 35.8% patients with unscarred uterus, emergency USG diagnosis of placenta previa was done.

MRI was done in 22 cases of scarred uterus , out of which 8 cases showed placental invasion into the myometrium. Among these 8 cases, only 3 cases had intraoperatively confirmed invasion. 59.1% cases with scarred uterus and 40.8% cases with unscarred uterus were multi- gravidae.

Majority of the unscarred uterus (92%) were nulliparous and only 8% with scarred uterus were nulliparous women. Among the primiparous women, 73.4% had scarred uterus (scarring due to prior myomectomy, D & C) and 26.4% had unscarred uterus. Among the multi-parous women, 90.3% had scarred uterus and 29% had unscarred uterus. Parity status showed significant difference between the scarred and unscarred uterus.

80.5% of women with scarred uterus and 19.4% with unscarred uterus had abortions. Scarred uterus showed statistically significant associations with abortions.

Mean gestational age in unscarred uterus was 36.51weeks and in scarred uterus was 35.53weeks.

SCARRED UTERUS

Majority of the patients had one or two LSCS (54.61%) as mode of delivery. 10.8% underwent D and C previously. One patient had history of previous myomectomy.

Among the unscarred uterus, 82% of patients underwent emergency LSCS and 18% underwent elective LSCS. Among the scarred uterus, 85% of patients underwent emergency LSCS and 15% underwent elective LSCS.

Table 2: Emergency LSCS and Elective LSCS

PLACENTATION

Among cases of scarred uterus, low lying placenta was seen in 20% and complete placenta previa was seen in 80%. Among cases of unscarred uterus, low lying placenta was seen in 54% cases and complete placenta was seen in 56%. cases Among cases of scarred uterus, 51.25% had anterior placenta and 48.75% had posterior placenta. Among cases of unscarred uterus, 73% had posterior placenta and 28% had anterior placenta. Anterior location of placenta is statistically associated with scarred uterus.

In scarred uterus, 82.5% had no invasion,10% had placenta accreta, 3.7% had increta and 3.7% had percreta. Placenta accrete spectrum is statistically associated with scarred uterus.

Table 3: Placentation among scarred and unscarred uterus

Statistically significant association was observed between the previous LSCS and complete placenta previa.

Anterior location of placenta is statistically associated with scarred uterus.

Placenta accrete spectrum showed statistically significant association between the previous LSCS.

60% cases of scarred uterus had antepartum hemorrhage and 40% cases of unscarred uterus had antepartum hemorrhage.

APH did not show statistically significant association with previous LSCS.

74.5% cases of scarred uterus and 25.4% cases of unscarred uterus had PPH.

PPH showed statistically significant association with previous LSCS.

All patients who underwent caesarean hysterectomy had scarred uterus (21.25%). Caesarean hysterectomy showed statistically significant association with previous LSCS

50% cases of scarred uterus and 50% cases of unscarred uterus needed compression sutures. B-Lynch sutures was applied to 12 cases (5 scarred and 7 unscarred). Hayman sutures was applied to 5 cases ( 3 scarred and 1 unscarred).

68% cases of scarred uterus and 32% cases of unscarred uterus needed uterine artery ligation.

Table 4 : Association of uterine artery ligation with previous LSCS

79.1% cases of scarred uterus and 20.8% cases of unscarred uterus underwent iliac artery ligation. Scarred uterus showed statistically significant association with iliac artery ligation.

Table 5 : Association of iliac artery ligation with previous LSCS

One patient with scarred uterus underwent bakri balloon procedure. 4 patients with scarred uterus had accidental intraoperative bladder injury. Bladder injury showed significant association with scarred uterus.

In the present study, Incidence of placenta previa among scarred uterus was 1.32% and in unscarred uterus was 0.67%.

Table 6: incidence of placenta previa among scarred and unscarred uterus in various studies.

In a study by Crane JM et al, the mean maternal age of patients with placenta previa was 30years. ⁽¹⁷⁾ Nair DB et al’s study showed that the mean age in the scarred uterus group was 28.4years and in the unscarred uterus group, it was 25.8years. ⁽¹⁸⁾

A study by Mathuriya et al ⁽¹³⁾, showed that the number of unbooked cases in both scarred and unscarred was high. In a study by Hassan S et al, 6 cases (32%) were booked and 13 cases (86%) were unbooked ⁽¹⁹⁾ In the present study, 78.75% pregnancies were booked in the scarred group and 78% pregnancies were booked in the unscarred group.

USG diagnosis

USG guided diagnosis confirmation is encouraged. Sonographic detection of anterior placenta and doppler ultrasound should be carried out to rule out placenta accreta to reduce the morbidity associated with placenta previa. ⁽¹⁵⁾ In the present study 64.1% patients with scarred uterus and 35.8% patients with unscarred uterus had a prior USG diagnosis.

Gravida

In a study by Shrigiriwar M et al, majority of the patients with placenta previa were multigravidae ⁽¹²⁾. In the present study, majority of the patients were multigravidae and showed a statistical significant association of multigravida with scarred uterus.

Parity

A study by Parikh PM et al, showed that majority of patients in the scarred group ( 42%) and unscarred group (64%) were multiparous ⁽¹⁴⁾. Thus, we could conclude that increasing parity increases with risk of placenta previa.

Abortions

A study by Mathuriya et al   ⁽¹³⁾,   showed   significant association of placenta previa following curettage (p value 0.002). Abortions also play a major role in scaring of uterus leading to placenta previa, as they increase the chances of patients undergoing dilatation and curettage.

Mean gestational age

A study by Upreti R et al, 62% presented with gestational age 28 to 37 weeks ⁽²⁰⁾. In a study by Ahemed SR et al, the mean gestational age of placenta previa cases was 37.3weeks.  In the present study, the mean gestational age in unscarred uterus was 36.51weeks and in scarred uterus it was 35.53weeks.

SCARRED UTERUS

In a study by Nair et al, among the various obstetric interventions leading to scarring, previous caesarean section was found to be the most important predisposing factor, followed by dilatation and curettage. ⁽¹⁸⁾

Previous LSCS

An increase in the number of previous caesarean section increases the chances of placenta previa in subsequent pregnancies. In a study by Shrigiriwar M et al , among all cases of scarred uterus, 80% had one previous caesarean section, while 15% had two previous sections and 4.5% had three previous caesarean sections. ⁽¹²⁾.

Previous Dilatation and Curettage

In a study by Shrigiriwar M et al, 33% of the patients in scarred uterus had a history of previous one dilatation and curettage, while only 11% of the patients in unscarred uterus had one dilatation and curettage. ⁽¹²⁾ A study by Nair DB et al showed 17.2% patients had history of dilatation and curettage. ⁽¹⁸⁾

Type of placenta previa

A study by Parikh PM et al showed that 72.7% cases in the unscarred group and 59.5% in the scarred group had low lying placenta. 27.2% cases in the unscarred group and 40.5% cases in the scarred group had complete placenta. ⁽¹⁴⁾

Location of placenta

In the present study, majority of cases with scarred uterus had anterior placenta and majority of cases with unscarred uterus had posterior placenta. A study by Parikh PM

et al showed that 60.7% cases of scarred uterus had anterior placenta previa while majority(63.63%) of patients with non-scarred uterus had posterior placenta. ⁽¹⁴⁾

Placenta accrete spectrum

In a study by Crane JM et al, 1.98% of placenta previa cases had placenta accrete. ⁽¹⁷⁾ In a study by Shrigiriwar, only 6 cases of 100 had invasive placenta, 3% of cases with scarred uterus had placenta accreta while 2.9% with unscarred uterus had placenta accreta. 4.5% of the cases with scarred uterus had placenta percreta.

Antepartum hemorrhage

In a study by Crane JM et al, 67.88% of the placenta previa cases had antepartum haemorrhage. ⁽¹⁷⁾ A study by Nair DB et al ⁽¹⁸⁾ showed that the occurrence of antepartum haemorrhage was more in the scarred group when compared to the non- scarred group and the finding was statistically significant.

Postpartum hemorrhage

In a study by Crane JM et al, 18.48% of the placenta previa cases experienced postpartum hemorrhage. ⁽¹⁷⁾ In a study by Hassan S et al, 57.9% of placenta previa cases experienced postpartum hemorrhage. ⁽¹⁹⁾

INTRAOPERATIVE INTERVENTIONS

Surgical injuries are due to the invasion of the bladder in placenta accreta together with multiple adhesions as a result of repeated caesarean delivery. ⁽²¹⁾ Excessive bleeding observed during surgery in placenta previa cases requires further modification in the procedure to control bleeding.

Caesarean hysterectomy

A study by Crane JM et al showed 5.28% of patients with placenta previa underwent hysterectomy. Previous caesarean delivery is a predictive factor for hysterectomy among patients with placenta previa. ⁽¹⁷⁾

Compression sutures

In a study by Shrigiriwar M et al, uterine compression sutures were used in 18% of the cases with scarred uterus and 2.9% of the cases with unscarred uterus. ^[12] In a study by Parikh PM et al, 6.06% cases in the unscarred group and 5.06% in the scarred group required uterine compression sutures. In this study, compression sutures were seen equally in both groups. ^[14]

Uterine artery ligation

A study by Surendra et al showed that 12.9% cases with scarred uterus and 2.08% cases with unscarred uterus underwent uterine artery ligation. ⁽²⁷⁾ A study by Mathuriya et al ⁽³¹⁾ showed need for uterine artery ligation in 20% cases with scarred uterus and 5.6% cases with unscarred uterus.

Iliac artery ligation

Bleeding in cases of placenta previa can be controlled very well with bilateral internal iliac artery ligation and the need for blood transfusion is greatly minimized to almost nil. ⁽²²⁾ In a study by Camuzcuoglu H et al, IIA ligation resulted in control of bleeding in 18/24 women (75%).

Bakri balloon

A meta-analysis by Nankali A et al ⁽²³⁾ showed that prophylactic internal iliac artery balloon occlusion in patients with placenta previa or placenta accreta spectrum has benefits such as reduced intraoperative blood loss, reduced hysterectomy and increased gestation (weeks).

Bladder injury

In a study by Ahmed S et al, 13.2% patients with placenta previa developed intraoperative bladder injury. ⁽²⁴⁾ A study by Shrigiriwar M et al showed bladder injury only in 4 cases of a total of 100 and all of them were cases of scarred uterus.

There is significant association of placenta praevia with previous surgery on uterus. Primary prevention in the form of reduction in the rate of primi caesearean section must be done in order to prevent likelihood of placenta previa in scarred uteri. Morbidity and mortality associated with placenta praevia and pathological placental adherence can be curtailed by routine screening of the scarred obstetric population for placental localization at an appropriate gestational period. The emphasis should be on institutional delivery in a tertiary care centre with multidisciplinary care i.e. involvement of senior obstetrician, neonatologist, sonologist and haematologist. Early diagnosis by Ultrasound and planned delivery should be the goal.

1. Latif L, Iqbal UJ, Aftab MU. Associated risk factors of placenta previa a matched case control study. Pak J Med Health Sci 2015;9:1344-6.
2. Hung TH, Hsieh CC, Hsu JJ et al. Risk factors for placenta previa in an Asian Int J Gynecol Obstet 2007;97:26-30.
3. Ahmed SR, Aitallah A, Abdelghafar HM et Major placenta previa: Rate, maternaland neonatal outcomes experience at a tertiary maternity hospital, Sohag, Egypt: A Prospective study. J Clin Diagn Res 2015;9:QC17-9.
4. Williams Obstetrics, 24th edition, chapter 41 obstetrical hemorrhage, page 800

5. Ananth CV, Wilcox AJ, Savitz DA et al. Effect of maternal age and parity on the risk of uteroplacental bleeding disorders in pregnancy. Obstetrics & Gynecology. 1996;88(4):511-6.
6. Stanton CK, Holtz SA. Levels and trends in cesarean birth in the developing Stud Fam Plann. 2006;37(1):41–48.
7. Lama S, Ranjit S. Study on maternal and immediate fetal outcome of placenta Nepal J Obstet Gynaecol. 2016;22(2):24-7.
8. Kavitha B, Hota BM. Clinical study of placenta previa in scarred and unscarred J Dr. NTR University Health Sci. 2018;7(1):13
9. Cunningham FG, Leveno KJ, Bloom SL et Obstetric haemorrhage. In: Williams Textbook of Obstetrics, 22nd ed. New York: McGraw-Hill, 20 ;809-823
10. Onwere C, Urganci IG, Cromwell DA et al.Maternal morbidity associated with placenta previa among women who had elective caesarean section. European J Obst Gyn Repro Bio. 2012;159:62-6
11. Rosenberg T, Pariente G, Sergienko R et al. Critical analysis of risk factors and outcome in placenta previa. Arch Gynecol Obstet. 2011;284:47-51
12. Shrigiriwar M, Kesarwani S, Ramteke Feto-maternal Outcome in Placenta Previa in Scarred versus Non-scarred Uterus. International Journal of Scientific Study. Feb
13. Mathuriya, G., & Lokhande, P. (2013). Comparative Study of Obstetrics Outcome Between Scarred and Unscarred Uterus in Placenta Previa Cases. Indian Journal Clin Pract, 24.
14. Parikh, P. M., Makwana, S., Shah, S., & Vithalani, V. (2016). Feto-Maternal Outcome in Placenta Previa in Scarred Uterus Vs Non Scarred Uterus. IOSR Journal of Dental and Medical Sciences (IOSR-JDMS), 15(1):69-73.
15. Surendra, Santosh Khajotia A Prospective Observational Study to Know the Incidence of Placenta Previa and Comparing its Effect on Fetomaternal Outcome in Scarred and Unscarred Uterus at A Tertiary Care Centre