What is intrapartum haemorrhage?

Antepartum haemorrhage (APH) is defined as bleeding from or in to the genital tract, occurring from 24+0 weeks of pregnancy and prior to the birth of the baby. The most important causes of APH are placenta praevia and placental abruption, although these are not the most common.

Types 1 and 2 are classified as minor placental praevia as these typically result in minor antepartum haemorrhaging. Types 3 and 4 are referred to as major placental praevia due to the risk of heavy haemorrhaging in the case of a rupture due to the location of placental attachment.

1. Antepartum Hemorrhage atrendynurse DC Dutta’s OBSTETRICS including Perinatology and Contraception (Eighth Edition)

2. Antepartum Hemorrhage DEFINITION: It is defined as bleeding from or into the genital tract after the 28th week of pregnancy but before the birth of the baby (the first and second stage of labor are thus included). The 28th week is taken arbitrarily as the lower limit of fetal viability. The incidence is about 3% amongst hospital deliveries.

3. CAUSES The causes of antepartum hemorrhage fall into the following categories. The hospital figures do not give a true picture of the incidence of the different varieties. However, on an average, the incidence of placenta previa , abruptio placentae and the indeterminate group is almost the same.

4. PLACENTA PREVIA DEFINITION: When the placenta is implanted partially or completely over the lower uterine segment (over and adjacent to the internal os ) it is called placenta previa . The term previa (L, in front of) denotes the position of the placenta in relation to the presenting part.

5. INCIDENCE About one-third cases of antepartum hemorrhage belong to placenta previa . The incidence of placenta previa ranges from 0.5% to 1% amongst hospital deliveries. In 80% cases, it is found in multiparous women . The incidence is increased beyond the age of 35 years, with high birth order pregnancies and in multiple pregnancy. Increased family planning acceptance with limitation and spacing of birth lowers the incidence of placenta previa .

6. ETIOLOGY The exact cause of implantation of the placenta in the lower segment is not known. The following theories are postulated . Dropping down theory: The fertilized ovum drops down and is implanted in the lower segment . Poor decidual reaction in the upper uterine segment may be the cause. Failure of zona pellucida to disappear in time can be a hypothetical possibility. This explains the formation of central placenta previa .

7. Persistence of chorionic activity in the decidua capsularis and its subsequent development into capsular placenta which comes in contact with decidua vera of the lower segment can explain the formation of lesser degrees of placenta previa . Defective decidua , results in spreading of the chorionic villi over a wide area in the uterine wall to get nourishment. During this process, not only the placenta becomes membranous but encroaches onto the lower segment. Such a placenta previa may invade the underlying decidua or myometrium to cause placenta accreta , increta or percreta

8. Big surface area of the placenta as in twins may encroach onto the lower segment. The high risk factors for placenta previa are — ( a) Multiparity ( b) Increased maternal age (> 35 years) (c) History of previous cesarean section or any other scar in the uterus (myomectomy or hysterecotomy ) (d) Placental size (mentioned before) and abnormality ( succenturiate lobes) ( e) Smoking — causes placental hypertrophy to compensate carbon monoxide induced hypoxemia ( f ) Prior curettage.

9. TYPES OR DEGREES: There are four types of placenta previa depending upon the degree of extension of placenta to the lower segment . Type—I (Low-lying) : The major part of the placenta is attached to the upper segment and only the lower margin encroaches onto the lower segment but not up to the os . Type—II (Marginal) : The placenta reaches the margin of the internal os but does not cover it.

10. Type II posterior placenta previa . ( The effective reduction of the anteroposterior diameter of the inlet in contrast to type II anterior placenta previa )

11. Type—III (Incomplete or partial central) : The placenta covers the internal os partially (covers the internal os when closed but does not entirely do so when fully dilated). Type—IV (Central or total) : The placenta completely covers the internal os even after it is fully dilated . For clinical purpose , the types are graded into mild degree (Type-I and II anterior) and major degree (Type-II posterior , III and IV) .

12. Degrees of placenta previa with findings on ultrasound examination

13. Dangerous placenta previa is the name given to the type-II posterior placenta previa . ( 1) Because of the curved birth canal major thickness of the placenta (about 2.5 cm ) overlies the sacral promontory, thereby diminishing the anteroposterior diameter of the inlet and prevents engagement of the presenting part. This hinders effective compression of the separated placenta to stop bleeding. ( 2) Placenta is more likely to be compressed, if vaginal delivery is allowed. ( 3) More chance of cord compression or cord prolapse. The last two may produce fetal anoxia or even death.

14. CAUSE OF BLEEDING As the placental growth slows down in later months and the lower segment progressively dilates, the inelastic placenta is sheared off the wall of the lower segment. This leads to opening up of uteroplacental vessels and leads to an episode of bleeding. As it is a physiological phenomenon which leads to the separation of the placenta , the bleeding is said to be inevitable . However, the separation of the placenta may be provoked by trauma including vaginal examination, coital act, external version or during high rupture of the membranes.

15. The blood is almost always maternal , although fetal blood may escape from the torn villi especially when the placenta is separated during trauma . The mechanisms of spontaneous control of bleeding are: ( 1) Thrombosis of the open sinuses. (2) Mechanical pressure by the presenting part. ( 3) Placental infarction.

16. Placental migration Ultrasonography at 17 weeks of gestation reveals placenta covering the internal os in about 10% of cases. Repeat ultrasonography at 37 weeks showed no placenta in the lower uterine segment in more than 90% of cases. Lower uterine segment expands from 0.5 cm at 20 weeks to more than 5 cm (10 fold) at term. The term placental migration (though misnomer) could be explained in two ways : ( i ) with the progressive increase in the length of lower uterine segment, the lower placental edge relocates away from the cervical os ( ii) due to trophotropism (growth of trophoblastic tissue towards the fundus), there is resolution of placenta previa .

17. CLINICAL FEATURES SYMPTOMS: The only symptom of placenta previa is vaginal bleeding . The classical features of bleeding in placenta previa are sudden onset , painless , apparently causeless and recurrent . In about 5% cases, it occurs for the first time during labor, especially in primigravidae . In about one-third of cases, there is a history of “warning hemorrhage” which is usually slight.

18. The bleeding is unassociated with pain unless labor starts simultaneously . Obvious causes for the placental separation such as trauma or hypertension are usually absent . In majority of cases, bleeding occurs before 38 weeks and earlier bleeding is more likely to occur in major degrees. Asymptomatic cases may be detected by sonography or at the time of cesarean section.

19. SIGNS: General condition and anemia are proportionate to the visible blood loss . But in the tropics, the picture is often confusing due to preexisting anemia .

20. Abdominal examination: The size of the uterus is proportionate to the period of gestation. The uterus feels relaxed, soft and elastic without any localized area of tenderness. Persistence of mal presentation like breech or transverse or unstable lie is more frequent. There is also increased frequency of twin pregnancy. The head is floating in contrast to the period of gestation. Persistent displacement of the fetal head is very suggestive. The head cannot be pushed down into the pelvis. Fetal heart sound is usually present, unless there is major separation of the placenta with the patient in exsanguinated condition.

21. Slowing of the fetal heart rate on pressing the head down into the pelvis which soon recovers promptly as the pressure is released is suggestive of the presence of low lying placenta especially of posterior type ( Stallworthy’s sign ). Vulval inspection: Only inspection is to be done to note whether the bleeding is still occurring or has ceased , character of the blood—bright red or dark colored and the amount of blood loss—to be assessed from the blood-stained clothing.

22. Vaginal examination must not be done outside the operation theater in the hospital, as it can provoke further separation of placenta with torrential hemorrhage and may be fatal . It should only be done prior to termination of pregnancy in the operation theater under anesthesia, keeping everything ready for cesarean section.

23. CONFIRMATION OF DIAGNOSIS DIAGNOSIS : Painless and recurrent vaginal bleeding in the second half of pregnancy should be taken as placenta previa unless proved otherwise. Ultrasonography is the initial procedure either to confirm or to rule out the diagnosis.

24. I. Localization of Placenta ( Placentography ) Sonography Transabdominal ultrasound (TAS) Transvaginal ultrasound (TVS) Transperineal ultrasound Color Doppler fl ow study 3D Power Doppler study

25. Magnetic resonance imaging (MRI ) For better diagnosis of placenta previa and placenta previa accrete

26. II. Clinical By internal examination (double set up examination) Direct visualization during cesarean section Examination of the placenta following vaginal delivery

27. CLINICAL CONFIRMATION Double set-up examination (vaginal examination): It is less frequently done these days. The indications are : ( i ) Inconclusive USG report ( ii) USG revealed type I placenta or ( iii) USG facilities not available . It is done in the operation theater under anesthesia keeping everything ready for cesarean section . Palpation of the placenta on the lower segment not only conclusively confirms the clinical diagnosis but also identifies its degree.

28. Visualization of the placental implantation on the lower segment can be confirmed during cesarean section .

29. Examination of the placenta following vaginal delivery reveals: ( a) A tongue-shaped comparatively thin segment of placental tissue projecting beyond the main placental mass with evidences of degeneration. (b) Rent on the membranes is situated on the margin of the placenta. ( c) Abnormal attachment of thecord (marginal or membranous) is more common.

30. DIFFERENTIAL DIAGNOSIS Placenta previa is at times confused with other causes of bleeding occurring in later months of pregnancy. The most common one from which it has to be differentiated is bleeding from premature separation of a normally situated placenta ( abruptio placentae ). The differentiating features are described in a tabulated form. The local cervical lesions (polyps, carcinoma) can easily be differentiated by a speculum examination. However , both the conditions can co-exist. In circumvallate placenta , the bleeding is slight and the diagnosis is only made after examining the placenta following delivery.

31. COMPLICATIONS OF PLACENTA PREVIA MATERNAL: During pregnancy — Antepartum hemorrhage with varying degrees of shock is an inevitable complication. The first bout of hemorrhage is seldom severe but torrential hemorrhage can easily be provoked by injudicious internal examination. Co-existent placental abruption is about 10%. Malpresentation : There is increased incidence of breech presentation and transverse lie . The lie often becomes unstable. Premature labor either spontaneous or induced is common. Death due to massive hemorrhage during the antepartum, intrapartum or postpartum period.Operative hazards, infection or embolism may also cause death.

32. Labor in a woman with placenta previa complicated with prolapse of umbilical cord and footling.

33. Cont …. During labor: Early rupture of the membranes Cord prolapse due to abnormal attachment of the cord. Slow dilatation of the cervix due to the attachment of placenta on the lower segment . Intrapartum hemorrhage due to further separation of placenta with dilatation of the cervix. Increased incidence of operative interference .

34. Cont … Postpartum hemorrhage is due to: Imperfect retraction of the lower uterine segment upon which the placenta is implanted. Large surface area of placenta with atonic uterus due to preexisting anemia . Occasional association (15%) of morbidly adherent placenta (placenta accreta , increta, percreta ) on the lower segment. Placenta previa accreta is a serious complication that may cause maternal death . Often the placenta previa and accreta is managed by hysterectomy. Trauma to the cervix and lower segment because of extreme softness and vascularity. It should be remembered that because of antepartum anemic state, the patient may become shocked with relatively small amount of blood loss.

35. Cont …. Retained placenta and increased incidence of manual removal add further hazard to the postpartum shock. Increased incidence of retained placenta is due to : ( 1) Increased surface area and ( 2) Morbid adhesion. The risk of placenta previa being accreta in a woman with previous one cesarean section is 10–20% and it rises to about 50% with two or more prior cesarean section.

36. Cont … Puerperium: ( 1) Sepsis is increased due to : ( a) increased operative interference ( b) placental site near to the vagina and ( c) anemia and devitalized state of the patient . ( 2) Subinvolution ( 3) Embolism .

37. FETAL COMPLICATIONS IN PLACENTA PREVIA Low birth weight babies are quite common (15%) which may be the effect of preterm labor either spontaneous or induced. Repeated small bouts of hemorrhage while carrying on the expectant treatment can cause chronic placental insufficiency and fetal growth restriction . Asphyxia is common and it may be the effect of — ( a) early separation of placenta ( b) compression of the placenta or ( c) compression of the cord.

38. Cont ….. Intrauterine death is more related to severe degree of separation of placenta, with maternal hypovolemia and shock. Deaths are also due to cord accidents. Birth injuries are more common due to increased operative interference. Congenital malformation is three times more common in placenta previa . Maternal and fetal morbidity and mortality from placenta previa are significantly high.

39. MANAGEMENT PREVENTION : Placenta previa is one of the inherent obstetric hazards and in majority the cause is unknown . Thus to minimize the risks, the following guidelines are useful . — Adequate antenatal care to improve the health status of women and correction of anemia. — Antenatal diagnosis of low lying placenta at 20 weeks with routine ultrasound needs repeat ultrasound examination at 34 weeks to confirm the diagnosis. — Significance of “ warning hemorrhage ” should not be ignored. — Color flow Doppler USG in placenta previa is indicated to detect any placenta accreta . Where this is not possible, such women with an increased risk of placenta accreta , should be managed as if they have placenta accreta until proved otherwise.

40. AT HOME ( 1) The patient is immediately put to bed . ( 2) To assess the blood loss — ( a) inspection of the clothing soaked with blood (b) to note the pulse, blood pressure and degree of anemia ( 3) Quick but gentle abdominal examination to mark the height of the uterus, to auscultate the fetal heart sound and to note any tenderness on the uterus ( 4) Vaginal examination must not be done . Only inspection is done to see whether the bleeding is present or absent and to put a sterile vulval pad.