Do not carry out pelvic examination on a pregnant woman who is bleeding.
Always send a woman with vaginal bleeding in late pregnancy immediately to a maternity hospital. Consult if necessary.
Most common reasons for bleeding
Bleeding associated with onset of labour, contractions and opening of the cervix.
Bleeding caused by recent pelvic examination
Post-coital bleeding
Bleeding caused by a cervical polyp
Bleeding mucous membranes caused by vaginitis
Placenta praevia
Premature detachment of the placenta.
Investigations
A careful history is important. Avoid bimanual examination.
It is advisable to carry out a speculum examination if the origin of the bleeding is unclear.
Check the state of the foetus: verify the presence of heart sounds either with a Doppler or an ultrasound.
If the bleeding is heavy, insert an intravenous cannula and promptly send the patient by ambulance, accompanied by an escort, to a hospital.
Placenta praevia
Predisposing factors include previous uterine procedures, e.g. curettage and caesarean section.
Placenta praevia may be either
complete (obstructs the internal os completely),
partial (obstructs the internal os only partially) or
marginal (placenta encroaches on the internal os).
Bleeding usually starts without a clear provoking cause.
The bleeding is bright red, and the mother is usually pain free.
At the maternity hospital the diagnosis is confirmed with an ultrasound examination and treatment decisions are based on the maternal and foetal state, the amount of blood loss and the number of gestational weeks.
If the bleeding is not particularly heavy and the mother and foetus are both well, and, in particular, if the pregnancy is not near term a decision is often taken only to observe the situation.
If the bleeding is heavy and uncontrolled, a caesarean section will be indicated (partial or complete placenta praevia).
Instead of the placenta, also the blood vessels of foetal membranes (vasa praevia) may be located on the os of the uterus. The phenomenon is rare, but bleeding starting after the rupture of the membranes is dangerous to the foetus.
Premature detachment of the placenta (placental abruption)
Predisposing factors
Trauma to the abdominal area or shock even if the blow does not fall on the abdominal area
A sudden reduction in the uterine volume (for example, in association with a rupture of the foetal membranes)
Pre-eclampsia
Multiple pregnancy
Placenta praevia or bleeding during pregnancy
Alcohol and drug abuse as well as smoking
Symptoms vary according to the extent and severity of the detachment.
The most common signs and symptoms include pain and a taut and tender uterus.
Even when the mother presents with symptoms of shock, vaginal bleeding may remain fairly slight (extensive retroplacental bleeding).
Foetal ECG will show signs of hypoxia.
Clinical diagnosis is most important. Ultrasound examination is usually not needed.
At the maternity hospital the treatment usually consists of a caesarean section, either urgently or as an emergency, as well as the treatment of the haemorrhagic shock of the mother.
References
Tikkanen M. Placental abruption: epidemiology, risk factors and consequences. Acta Obstet Gynecol Scand 2011;90(2):140-9. [PubMed]
Fan D, Wu S, Liu L, et al. Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis. Sci Rep 2017;(7):40320. [PubMed]
Society for Maternal-Fetal Medicine (SMFM). Electronic address: pubs@smfm.org., Gyamfi-Bannerman C. Society for Maternal-Fetal Medicine (SMFM) Consult Series #44: Management of bleeding in the late preterm period. Am J Obstet Gynecol 2018;218(1):B2-B8. [PubMed]
Young JS, White LM. Vaginal Bleeding in Late Pregnancy. Emerg Med Clin North Am 2019;37(2):251-264. [PubMed]
Pavalagantharajah S, Villani LA, D'Souza R. Vasa previa and associated risk factors: a systematic review and meta-analysis. Am J Obstet Gynecol MFM 2020;2(3):100117. [PubMed]