Interpretation
The prevalence of placental abruption varies across regions. In the
present study, the incidence of placental abruption was 0.4%, which is
similar to that reported in the Nordic countries (0.4–0.5%) and is
lower than that reported for the US (0.6–1.0%).2Postpartum hemorrhage (PPH) is the most frequently reported maternal
morbidity associated with the placental abruption, and PPH, as a
consequence of placental abruption, elevates the incidence of maternal
blood transfusion. The rate of transfusion due to placental abruption in
the present study was 1.7%, which is lower than that reported in the
previous studies (2.4–14.6%).1 The distinctive
difference in maternal transfusion rate for women with placental
abruption may due to different diagnosis criteria for placental
abruption in each study. The diagnosis of abruption is primarily
clinical, but sometimes findings from the imaging, laboratory, and
postpartum pathologic studies can be used to support the clinical
diagnosis.1 However, to date, there is no gold
standard for diagnosing placental abruption.
The findings of the present study indicate that half of the placental
abruption cases occurred before the 37 weeks of gestation. Preterm birth
(PTB) is one of the most frequently reported obstetric outcomes
associated with the placental abruption.1 PTB has two
clinical subtypes, viz., spontaneous PTB and medically indicated PTB;
the latter occurs due to HDP.8 Placental abruption can
lead to both spontaneous and medically indicated PTB. Spontaneous PTB
due to placental abruption is thought to be the result of bleeding from
the separation of the placenta, which irritates the uterine lining and
stimulates uterine contractions leading to PTB.17Medically indicated PTB because of placental abruption is usually
conducted by CS to reduce the risk of maternal and perinatal morbidity
and mortality.18 The present study showed high
prevalence of CS (62.2%) for cases with placental abruption, and high
percentage of CS was before 37 weeks of gestation (Figure 2B),
suggesting that most cases of PTB were medically indicated.
Placental abruption is a complex complication of pregnancy. Although
several risk factors for placental abruption are known, its
etiopathogenesis is not fully understood. Ananth et al. reported that
instead of the number of previous deliveries, the maternal age was an
independent risk factor for placental abruption.19 The
findings of the present study are consistent with those reported by
Ananth et al. The underlying reason for why advanced maternal age
increases the risk of placental abruption is speculative. Most
abruptions appear to be related to a chronic placental disease process,
wherein, abnormalities in the early development of the spiral arteries,
which could be affected by maternal age, can lead to decidual necrosis,
placental inflammation, and possibly infarction, ultimately resulting in
vascular disruption and bleeding.20–22 A few studies
have reported the association between teenage pregnancy and placental
abruption. Kyozuka et al., using descriptive analysis, reported that
maternal age <20 years is responsible for the highest
occurrence of severe maternal complications such as HDP and placental
abruption.9 They concluded that low socio-economic
status of teenagers could be associated with the high occurrence of
severe maternal complications. The underlying reason for why teenage
pregnancy is an independent risk factor for placental abruption in the
present analysis is more speculative. However, the findings of the
present study must be interpreted with caution because teenage women are
likely to be associated with less education, low income, and
malnutrition, which have not been considered as confounding factors in
the present analysis. The placental abruption during teenage could be
due to direct mechanical events such as blunt abdominal trauma and/or
rapid uterine decompression, which are more eventful in young maternal
age.23