The other common cause for late bleeding is placenta previa. In this situation the placenta is attached very close to the cervix, or is even covering it (Figure 21.2). As the cervix dilates the edge of the placenta may detach and it starts bleeding. A woman with this condition generally has clear, bright red blood coming from her vagina. The amount may be less than with placental abruption, but in some cases it can be severe and life threatening. The bleeding is often painless, so the woman may not have noticed it happening for a while, for example during the night when she was in bed. The bleeding can be set off by sexual intercourse and it may be recurrent (stopping and starting again).

Three diagrams of the three classifications of placenta previa showing how it appears in the womb.

Figure 21.2 Placenta previa is classified on how close the placental edge is to the cervix. (a) Low placental implantation, but not intruding into the cervix. (b) Partial placenta previa. (c) Complete placenta previa.

In a woman with late pregnancy bleeding due to placenta previa, the uterus often feels soft when you palpate her abdomen, in contrast to the hard feeling of the uterus when bleeding is due to placental abruption.

The fetal head is generally not in the lower part of the uterus, which feels empty. This abnormal presentation may be a sign of placenta previa. Usually the fetal condition is normal, so you can detect a fetal heart beat when you listen with a fetoscope, and the mother reports the fetus is moving and kicking normally — but this is not always the case.

The diagnosis of placenta previa can only be confirmed by examining the woman with an ultrasound machine that can reveal the position of the placenta, or by vaginal examination in an operating theatre. Therefore you should refer her to a health facility with the necessary equipment to make a diagnosis.

Women with a suspected placenta previa should be referred to a District Hospital or Health Centre with an ultrasound machine or operating theatre.

Never do a vaginal examination yourself if a woman is bleeding in late pregnancy. This will worsen the situation and increase the risk to her and the fetus.

Last modified: Monday, 14 July 2014, 10:27 AM