Bleeding in the second and third trimesters of pregnancy: causes and emergencies

Why is bleeding in the second or third trimester an emergency?

After 14 weeks of pregnancy (weeks of amenorrhoea), vaginal bleeding is never harmless until its cause is known. It may come from the placenta and threaten both mother and baby, sometimes within minutes. Only an examination at the maternity unit can tell the difference. This is one of the situations in which it helps to know in advance the maternity unit where you plan to give birth in Paris and how to reach its emergency department.

Bleeding in the first trimester has other causes (miscarriage, ectopic pregnancy); these are covered in our article on bleeding in the first trimester.

What causes bleeding in late pregnancy?

The table below summarises the main causes and their usual signs. These pointers help you understand, not make a diagnosis yourself: only an assessment at the maternity unit can do that.

Placenta praevia is often known before any bleeding thanks to the second-trimester scan, which detects a low-lying placenta. A follow-up scan is then arranged in the third trimester (around 32 weeks), as the placenta often "moves up" as the uterus grows.

Placental abruption affects about 0.4 to 1% of pregnancies. Risk factors include high blood pressure and pre-eclampsia, smoking, cocaine, abdominal trauma (accident, fall, blow) and a previous abruption.

What should I do if I bleed during pregnancy?

• Do not wait for the bleeding to stop: go to the emergency department of the maternity unit where you are booked, or the nearest one.
• Do not drive yourself. If the bleeding is heavy, if you are in pain or feel unwell, call 15 (SAMU, the French emergency medical service) or 112 in France, or your local emergency number.
• Do not use a tampon, do not douche, and avoid sex.
• Note the time it started, how heavy it is (number of pads), the colour of the blood, any pain or contractions and the baby's movements.
• Bring your pregnancy notes, particularly your scan reports and your blood group card.

When should I go to the maternity emergency department?

Any bleeding after the first trimester needs to be seen the same day. Call 15 or 112 without delay if the bleeding comes with:

• heavy bleeding, flowing or soaking a pad in less than an hour;
• sudden, constant abdominal pain, or an abdomen as hard as wood;
• feeling faint, pale, sweaty, a racing heart or feeling as if you might pass out;
• fewer movements from the baby, or none;
• a severe headache or problems with your vision, which suggest associated pre-eclampsia;
• bleeding after a blow to the abdomen, even if it seemed minor.

What happens at the maternity emergency department?

The team has three aims: to check that you are coping with the blood loss, to make sure the baby is well, and to find the cause.

• For you: pulse, blood pressure, general condition, blood tests (blood count, clotting, blood group and antibody screen).
• For the baby: heart rate monitoring (CTG) and ultrasound.
• For the cause: ultrasound locates the placenta. If placenta praevia is known or suspected, internal (vaginal) examination is avoided. A speculum examination shows whether the blood is coming from the cervix or the vagina.

If your blood group is rhesus negative, an anti-D immunoglobulin injection is given within 72 hours of the bleeding, to prevent your body making antibodies against the baby's red blood cells. A Kleihauer test, done on a sample of the mother's blood, estimates how much of the baby's blood has entered your circulation so the dose can be adjusted.

How is bleeding in late pregnancy treated?

Placenta praevia

• Hospital admission and monitoring of mother and baby; preparation for a possible transfusion.
• Before 34 weeks, if a premature birth seems possible: corticosteroids to speed up the baby's lung maturity, and sometimes treatment to calm contractions.
• Once the bleeding has stopped, going home may be discussed case by case, with strict instructions and quick access to the maternity unit.
• Birth: a planned caesarean section if the placenta covers the cervix; a vaginal birth is sometimes possible if the placenta is low but does not cover it, depending on the distance measured on ultrasound. With major haemorrhage, an emergency caesarean may be needed whatever the stage of pregnancy.
• After a previous caesarean, the team looks for placenta accreta (a placenta abnormally attached to the wall of the uterus), which requires specific planning.

Placental abruption

• This is an absolute emergency. The team replaces lost blood and corrects any clotting problems that may come with it.
• If the baby is alive, the birth usually takes place quickly by caesarean section.
• If, sadly, the baby has died, a vaginal birth is generally preferred, under intensive monitoring, to spare the mother surgery while there are clotting problems. The team also provides psychological support; see our article on pregnancy loss and stillbirth.

Other causes

A lesion of the cervix or an infection is treated according to its type. Premature labour is managed according to the stage of pregnancy.

Can bleeding in late pregnancy be prevented?

It cannot always be avoided, but some measures reduce the risk:

• stop smoking and any drug use;
• have high blood pressure monitored and treated;
• wear your seat belt below your bump, across your hips, and get checked after any blow to the abdomen;
• if you have a known low-lying placenta: follow the advice you are given (sex, exertion, travel) and never dismiss bleeding;
• attend the recommended scans, which help anticipate the position of the placenta.

Patients followed at the practice give birth at Maternité Sainte-Félicité (Paris 15th) or Clinique Sainte-Thérèse (Paris 17th). If you have any bleeding, go to the emergency department of the maternity unit where you are registered; in a life-threatening emergency, call 15 or 112.

Frequently asked questions

General information article: it does not replace a medical consultation. In an emergency, call 15 or 112 in France, or your local emergency number.