The role of ultrasonography in prediction of obstetric hemorrhage

Obstetric haemorrhage is the single most significant cause of maternal mortality worldwide accounting for 25–30% of all maternal deaths. Life-threatening postpartum haemorrhage (PPH) occurs in approximately 1:1000 deliveries in the developed world. Although the risk of dying from pregnancy decreased dramatically during the last century, 60–90% of deaths from PPH are potentially preventable with better medical care.
Ultrasound is an unique diagnostic technique for many obstetric hemorrhage.
Typies of obstetric hemorrhage:

Antepartum (early and late) hemorrhage

• Early pregnancy hemorrhage: abortion (medical or spontaneous) and ectopic pregnancy
• Late pregnancy (antepartum) hemorrhage: placenta previa, placental abrubtion, placenta accreta (accreta, increta & percreta) and vassa previa.

Early pregnancy hemorrhage: abortion (medical or spontaneous) and ectopic pregnancy. Vaginal bleeding in the first trimester of pregnancy can be caused by several different factors. Bleeding affects 20% to 30% of all pregnancies. Transvaginal ultrasound is an excellent diagnostic imaging technique for early normal and complicated pregnancy. The hemorrhages arising from uterine anomaly, presence of subamniotic and subchorionic hematomas, abnormal placentation, abnormal embryonic location and the other pathological situations are well diagnosed by ultrasound in early gestational age.

Late pregnancy (antepartum) hemorrhage: Antepartum haemorrhage is defined as bleeding from the genital tract after 24 weeks of gestation and has an incidence of 2-5% of all pregnancies beyond 24 weeks. The most causes of antepartum bleeding are placental abruption, placenta previa, abnormal placentation and uterine rupture. Central and marginal subchorionic hemorrhages of placental abruption are well diagnosed by ultrasound examination. Placenta previa can be well diagnose by transvaginal ultrasound during all stages of pregnancy, especially in the second half of gestation. Abnormal placentation is also can be diagnosed by transvaginal ultrasound in early period, especially if placenta located on uterine scars, such as cesarean section. If the obstetric hemorrhage originated from uterine rupture, intra abdominal hematoma or fluid can be diagnosed by ultrasound examination.

Intrapartum hemorrhage
Intrapartum hemorrhage complicates about 5% of all deliveries. Uterine rupture, cervical rupture, epysiotomy, abruption placenta, placenta previa variations and prlolnged labor.

Postpartum hemorrhage

•  Early postpartum hemorrhage: uterine atony, uteine rupture, uterine inversion, retained products, invasive placentation, intrauterine hematom, myomas, coagulopathy and lacerations of genital tract (lower and upper)
•  Late postpartum hemorrhage: retained products, uterine enlargement, iInfections, subinvolution of placental site, coagulopathy and uterine varix
Postpartum haemorrhage (PPH)
The incidence of postpartum hemorrhage is about 1 in 5 pregnancies, but this figure varies widely due to differential definitions for postpartum hemorrhage. PPH can be divided into 2 types: early (<24 hours after delivery) and late (24 hours to 6 weeks after delivery). Most cases of PPH (>99%) are early.  PPH can be categorized as an abnormality of one or more of the following: uterine tone, retained tissue, trauma and coagulopathy. Uterine atony, defined as the lack of efficient uterine contractility after placental separation, is the most common cause of PPH and complicates approximatelly 1 in 20 deliveries. Diagnosis of uterine atony is difficut made by ultrasound, however, the ultrasound examination is usefull for if presence intrauterine hematoma, retained tissue, uterine fibroids. Abnormal placentation is abnormal attachment of the placenta to the uterine wall and includes accreta, increta, and percreta, depending on the extent of uterine invasion. Important risk factors are the presence of placenta praevia and a history of prior Caesarean deliveries. In generally, abnormal placentation can be diagnose by ultrasound antenataly. In addition, the ultrasound examination is usefull for retained tissue, uterine infection and the other pelvic organs pathologic situations.

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