Abruptio Placenta: An Analysis of Risk Factors and Perinatal Outcome

Vinitha Willsa, Jacob Abrahamb, Rajeev Ac

a. Department of Obstetrics and Gynaecology, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India; b. Department of Paediatrics, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India; c. Department of Community Medicine, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India*

Corresponding Author: Dr. Vinitha Wills, Department of Obstetrics & Gynaecology, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India. Email: drvinithajacob@gmail.com

Abstract

Abruptio placenta is an important cause of maternal as well as perinatal morbidity and mortality. This study is aimed to determine the risk factors and perinatal outcomes of the abruptio placenta in a tertiary care hospital. A case-control study was conducted in the Department of Obstetrics and Gynaecology and the Neonatology unit at Pushpagiri Medical College over a period of 2 years. Twenty-four cases of patients presenting with abruptio placenta and 100 mothers who came in labor without abruptio placenta acting as controls participated in the study. Early gestational age, preeclampsia, hypothyroidism, previous cesarean section, multiple pregnancy and history of threatened abortion were found to be associated with increased risk of abruptio placentae. Placental abruption was significantly associated with poor perinatal outcomes – such as low birth weight babies, poor Apgar scores, congenital malformations, and neonatal deaths.

Key words: Abruptio Placenta, Risk Factors, Perinatal-Fetal, Neonatal Outcome, Preeclampsia, Previous Cesarean

 

Introduction

Placental abruption is the premature separation of the normally implanted placenta before delivery of the foetus.1 Abruption in Latin means the disruption of the placental attachment to the uterus due to hemorrhage.2 It is a major cause of maternal morbidity and perinatal mortality.1 Literature indicates that abruptio placentae occur in 0.5-1% of all pregnancies3-5 and 1.2% in multiple pregnancies.6 Evidence from studies conducted in the Unites States and Norway portray an increase in incidence in present times.7,8 Studies are needed in India to delineate the risk factors pertaining to our scenario to anticipate and improve management.

Diagnosis of abruptio placentae is by typical clinical presentation of vaginal bleeding, abdominal pain, uterine tenderness and by identification of retroplacental clots at delivery.2

Abruptio placenta is a major obstetrical cause of third-trimester hemorrhage. The severe hemorrhage occurring is responsible for maternal complications like atonic postpartum hemorrhage, renal failure, disseminated intravascular coagulation and even maternal death.9,10 The premature placental separation and reduced oxygenation is thought to be responsible for the adverse perinatal outcome.11 Abruptio placenta is an important cause of high rates of preterm births,12 fetal growth restriction13 as well as perinatal morbidity and mortality.14

Extensive research over the years has proven preeclampsia, eclampsia12 and maternal smoking as major risk factors.13,15 Other risk factors identified for the onset of abruption were age, multiparity,16,17 intrauterine infection,18 multiple pregnancy6 and premature rupture of membranes (PROM).19-21

This study is aimed to identify risk factors for abruptio placenta and the resulting pregnancy outcome.

It would be expected that early diagnosis and appropriate management by the obstetrician and neonatologist in a tertiary care center with 24 hrs theater facilities, blood bank services and availability of neonatal ventilation would improve the final outcome of patients with abruption. This study forms an important tool to anticipate abruption and provide an early referral to such tertiary centers.

 

Objectives

To determine the risk factors and the fetal outcome in cases of abruptio placenta in a tertiary center.

 

Methodology

This was a case-control study conducted in the Departments of Obstetrics and Gynaecology and the Neonatal Unit of Pushpagiri Medical College from the period of January 1, 2013 till October 31, 2014.

Twenty-four patients admitted with clinical presentation of abruptio placenta – vaginal bleeding, pain abdomen or uterine tenderness was included in the study as cases. Diagnosis was confirmed by the presence of retroplacental clots later on by placental examination.

Hundred cases acted as controls, which were the first 5 women of every month who went into labor, irrespective of whether they were delivered by cesarean or vaginal route. Women presenting with antepartum hemorrhage and history of previous caesarean were excluded from the control group.

A questionnaire which included the demographic profile and risk factors of the mothers was used to collect data. This included details like maternal age, gravida, profile of referral and the gestational period at which abruption occurred. Details of associated medical problems (preeclampsia, gestational diabetes mellitus (GDM), hypothyroidism and infertility) and obstetrical risk factors (previous caesarean, multiple pregnancies, growth restriction, history of threatened abortion, previous preeclampsia and PROM) were noted. Per-operative findings were recorded. These same parameters were compared in mothers in the control group – the ones without abruptio placenta. Similarly in both groups, fetuses with congenital malformations, intrauterine demise, birth weights, gender, and an Apgar score ≤5 at 1 min and 5 min were recorded.

Neonatal outcome was also noted. In the control group, only 23 babies (23%) were admitted in the neonatology unit and compared to 100% of babies in the abruptio placentae group.

Statistical analysis was performed using Chi-square test for differences in qualitative variables. A p value <0.05 was considered significant. Odds ratio (OR) was calculated with 95% confidence intervals (CI) to exclude chance. Since cases and controls in our study were matched for age, negating the effect of potential confounders, we carried out only univariate analysis. Adjusted OR, therefore, was not calculated nor reported.

 

Results

The case-control study conducted in the Department of Obstetrics and Gynaecology, Pushpagiri Medical College included 24 patients with abruptio placenta as cases. The parameters studied in them were compared to 100 patients who went into labour and acted as controls to the study group.

The maternal study variables and their statistical significances are shown in Table 1. The demographic features, which showed significant association with maternal abruption were a referral from other centers and early gestational age. Age and multigravida status which have been proven to have a significant association in worldwide studies were not significant in this study. Medical complications like preeclampsia and hypothyroidism were found to be significant risk factors. There was significant association of abruption with obstetrical complications like threatened abortion, previous cesarean sections, history of previous preeclampsia and multiple pregnancies. There was a noted higher incidence of oligohydramnios, intra-uterine growth restriction (IUGR), and Rh-negative pregnancies in the study group though there was no statistical significance. The only significant maternal complication noted was postpartum hemorrhage.

Table 1. Description of maternal study variables

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Adjusted OR was not required and hence not reported in our analysis because cases and controls were age-matched and potential confounders were mostly equally distributed between the groups. Table 2 shows the univariate OR and their 95% CIs. Women who were pregnant now with a previous history of preeclampsia had an inconclusively higher odds for abruption (OR 9.09; CI 0.78-104), while those with preeclampsia during the present pregnancy had a significant nine-fold risk for abruptio placenta (OR 9.49; CI 3.10-29.0).

Table 2. OR and CI of maternal variables

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The odds for developing abruptio placenta was significantly associated with the previous Caesarean section (OR 26.05; CI 2.88-235). A significantly higher odds for abruptio placenta was seen in those with a previous history of threatened abortion (OR 10.78; CI 2.46-47.6). Those women who had multiple gestation had an OR of 9.0 (CI 0.78-103), which was statistically significant. Mothers with hypothyroidism during pregnancy also seemed to have significantly increased the risk of abruptio placenta (OR 2.83; CI 1.03-7.78).

There was an increased odds to having an abruptio placenta in Rh-negative pregnancies (OR 1.8; CI 0.51-6.32), which was not statistically significant. In those with babies showing IUGR OR was 3.42 (CI 0.71-16.47). Among those with a history of the polycystic ovarian disease (PCOD) OR was a non-significant 2.18 (CI 0.37-12.62).

A pregnancy associated with GDM (OR 0.75; CI 0.19-2.81) and PROM (OR 0.29; CI 0.03-2.34) were found to have a neutral odds of being associated with abruptio placenta. The deductive possibility of postpartum hemorrhage was 6 times more in patients with abruptio placenta (OR 6.31; CI 1.55-25.7), though such a conclusion cannot be warranted in a case-control analysis.

The profile of babies delivered in the study and control groups is shown in the first part (Table 3a) of Table 3 and the profile of babies admitted to the neonatal intensive care unit (NICU) forms the latter part of Table 3b. Among the 24 mothers with placental abruption, there were 25 live babies delivered (including 1 twin delivery and a triplet birth and excluding the 2 intrauterine fetal demises). Placental abruption was significantly associated with lower birth weights and adverse perinatal outcome (poorer Apgar scores, congenital malformations, intra-uterine fetal demise, need for NICU admission and neonatal deaths).

Table 3. Profile of babies in the two groups

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In the study group, all 25 babies (100%) required admission in the NICU while only 23% in the control group required admission to the NICU, which was highly statistically significant. Among the babies in the study group needing management in the NICU, significantly more needed some form of respiratory support (oxygen, continuous positive airway pressure [CPAP] or ventilation). Individual interventions, when analyzed among those admitted in NICU, did not show any difference between the two groups as regards need for oxygen, but significantly more babies born to cases required CPAP support in the study group. The need for ventilation also was highly significantly associated with the babies born to the case group. Consequently, neonatal deaths also were significantly more among the babies born to mothers with abruption (P<0.001).

 

Discussion

Abruptio placenta is considered to be a grave obstetrical emergency – because if not diagnosed and managed at the earliest – it results in maternal and perinatal morbidity and mortality.

The majority of the studies in the West proved an association between higher maternal age (>35 years) and multigravida. Kramer quoted an odds of developing abruptio placenta to be 1.5 if maternal age exceeded 35 years.22 Contrary to these studies, our study did not show any significant association between abruptio placenta and higher maternal age. In this study, 83.4% cases occurred in the younger age group between 21 and 30 years. Pariente et al reported a similar incidence (67.7%) in this age groups.4 Abruptio placenta was seen to occur in 58.3% of multigravida though there was no significant association. This was similar to studies by Kramer MS et al22 and Wandabwa et al.23 The study showed a significant association between abruptio placenta and preterm deliveries. This was similar to the association reported by Pariente et al.4 Multiple logistic regression analysis by them revealed decreasing gestation age to be significantly associated with the abruptio placenta. Sheiner et al reported a similar rate of 05.4% abruption at preterm gestation.17

This study was conducted in a tertiary level hospital where operative services, blood bank facilities and high quality of neonatal care were available. So 62.5% patients with abruptio placenta were those referred from peripheral centers; and 75% of the mothers underwent emergency cesarean in view of achieving a better maternal and fetal outcome. There was statistically significant association here.

Studies have shown that preeclampsia and smoking are the most important risk factors associated with abruption. However, smoking was not a common habit of women in our society and hence not analyzed. Ananth CV et al has reported that the relative risk of abruptio is 3.8 times for severe preeclampsia.3 Significant number of our cases (41.6%) had preeclampsia, which conformed to studies reported by Abu-Heija A et al16 and Kramer MS et al (OR 2.05 CI 1.39-3.04).22 Pariente et al concurred with these earlier studies noting an OR of 2.86 (CI 2.46-3.32).4 Hypothyroidism (33.3%) and PCOD (08.3%) were the other associated problems identified in this study. Further evaluation of hypothyroidism as a risk factor for abruptio placenta appears to be necessary. Infertility with PCOD being one of the prime causes was found to have significant association by Pariente et al with a two-fold increase in risk.4

Wandabwa et al reported that women with previous caesarean delivery had ten times higher risk of abruptio placenta (when adjusted for confounders) in the present pregnancy.23 They noticed that mothers with a history of repeated bleeding during the antenatal period also carried a higher risk for abruptio placentae.23 A fourth of cases had a history of threatened abortion, and 20.8% had a cesarean in previous pregnancies both of which were highly significant in our study. Multiple pregnancies are reported to be at higher risk for abruption as proven by Ananth CV et al.6 Only 08.3% of mothers in our study group had multiple pregnancies (one being a twin and the other a triplet pregnancy), but it was significantly associated with abruptio placenta. Studies by Ananth CV et al prove a strong association between PROM and abruption.6 While PROM was also an important risk factor in the studies by Pariente et al (OR 1.29 CI 1.07-1.56)4 and Kramer MS et al (OR 2.38 CI 1.55-3.65),22 Wandabwa et al23 did not find any significant association. Our study could not prove a relationship between PROM and abruptio placenta.

Abruptio placenta is identified to be an important cause for fetal and perinatal morbidity. There was a significant correlation between low birth weight and abruptio placenta. Our results were similar to 54.9% found in the study conducted by Pariente et al.4 This could be because the pregnancies required earlier termination due to the severity of the disease. Higher odds to deliver low birth weight babies was found in mothers with abruptio placenta by Wandabwa et al (OR 30.1 CI 12.9-70.2) and Kramer MS et al (OR 3.99 CI 2.75-5.77).23,22

Hladky et al and Sheiner et al reported that mothers with male babies had a higher risk of the abruptio placenta.17,24 This was a constant phenomenon noted in several studies despite there being no explanation to this. There were no similar findings in this study. In the study group, 44.0% of babies had poor Apgar scores at 1 min and 4.0% at 5 min compared to none in controls. Pariente et al similarly reported 44.6% of babies with poor Apgar scores and 16.95% of congenital malformation.4 Among the babies born to mothers with abruptio, four babies (14.8%) were found to have congenital anomalies and only 1.0% of babies in the control group had anomalies (a case of hypospadias with bifid scrotum). The anomalies noted in the study group were a case each of congenital diaphragmatic hernia and dextrocardia and two had limb anomalies in the form of congenital talipes equinovarus and amniotic band with amputation of left lower limb. However, this statistically significant difference between the two groups was much higher than the incidence reported by Hladky et al (1.3%) in mothers with abruptio placentae.24

Wandabwa et al reported a very high incidence (52.0%) of still born.23 There were only 7.4% of still borns in our study group. Yet it was higher than our control group, which had no still born babies. Various reasons such as low birth weight, prematurity, poor Apgar scores contributed to there being 20.8% of neonatal deaths in the study group while there was only 1.0% in the control group.

The only significant maternal complications noted were five cases of atonic postpartum hemorrhage, which could be managed with blood products, medical and surgical methods. In spite of 100% admission into the NICU of babies born in mothers with abruption, mortality among these babies was less and was not statistically significant. This favorable outcome was attributable to timely referral from peripheral centers, rapid intervention and good neonatal care at our center.

 

Conclusion

Many variables identified in this study were found to be consistent with known risk factors in other studies while others were not. This study reinforces that the occurrence of abruptio placenta is associated with risk factors like early period of gestation, preeclampsia, hypothyroidism, previous cesareans, threatened abortion and multiple pregnancy. Abruptio has an adverse impact on maternal and perinatal outcome. Babies with congenital malformations and poorer outcome were more in abruptio.

With the increasing incidence of caesarean section, hypothyroidism and preeclampsia in the present times, a rise in the incidence of the abruptio placenta should be anticipated. Ideally all women at risk should have regular and frequent antenatal checkups at a tertiary center where operating facilities, blood transfusion services and neonatal care are available. Immediate intervention by the obstetrician and active resuscitation by the neonatologist is the key to improve maternal and perinatal outcome in women presenting with abruptio placenta.

 

End Note

Author Information

  1. Dr.Vinitha Wills, Associate Professor, Department of Obstetrics and Gynaecology, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India. Email: drvinithajacob@gmail.com

  2. Dr.Jacob Abraham, Professor & Chief (Neonatology), Department of Paediatrics, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India

  3. Dr.Rajeev A, Professor, Department of Community Medicine, Pushpagiri Medical College, Thiruvalla, Pathanamthitta, Kerala, India

 

Acknowledgments

None

 

Conflict of Interest

None Declared

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