Key messages

• The clotting medicine tranexamic acid (TXA) given during caesarean birth does not prevent heavy bleeding when blood loss is measured by collecting blood and weighing surgical sponges, or when health providers estimate the amount of blood loss. When blood loss is calculated using the proportion of red blood cells in blood before and after the caesarean birth, there is likely a slight reduction in heavy bleeding.

• TXA probably does not make a difference in the number of women who need further treatment to control heavy bleeding.

• The effect of TXA on harmful effects is uncertain.

What is the issue?

Heavy bleeding after giving birth (postpartum haemorrhage) is a common and sometimes life-threatening complication of birth. Most women receive drugs that stimulate the womb to contract (uterotonics) after vaginal or caesarean birth to prevent postpartum haemorrhage. Tranexamic acid (TXA) is a medication used to decrease blood loss in surgery and health conditions associated with increased bleeding. It works by helping to prevent the breakdown of blood clots. If a woman is bleeding heavily after birth, it decreases blood loss. We do not know if TXA can help prevent heavy bleeding after caesarean birth.

What did we want to find out?

We wanted to know if fewer women receiving TXA at the time of surgery had heavy bleeding after a caesarean section. We also wanted to find out if receiving TXA during surgery was associated with any harmful effects.

What did we do?

We searched for and selected all studies that addressed this question. We used a checklist to make sure we only included studies that we could trust. We made judgements about the quality of the studies before comparing and summarising the results of the studies. Lastly, we rated our confidence in the findings.

Why is this important?

We need to find out whether TXA is effective in preventing heavy bleeding after birth when given to women at the time of a caesarean birth. If TXA works, it could reduce excessive blood loss, the use of further treatment, and possibly complications from heavy bleeding and death.

What did we find?

We identified six studies with a total of 15,981 women that looked at the effects of preventive TXA. We found that TXA results in little to no difference in heavy bleeding after birth when blood loss is measured by collecting blood and weighing surgical sponges, or when health providers estimated the amount of blood loss, compared to placebo (dummy treatment). TXA likely results in a slight reduction of heavy bleeding when blood loss is calculated using the proportion of red blood cells in the blood before and after the caesarean birth. We are very uncertain about the effect of TXA on maternal death, and there is no evidence on the effect of TXA on women developing serious illness.

It is likely that TXA has no effect on the need to receive a blood transfusion, and makes no difference to whether a women needs further surgical treatment. We are very uncertain about the effect of TXA on blood clots. TXA results in little to no difference to whether women require additional drugs to help the womb contract, and we are very uncertain about the effect of TXA on the need for surgical removal of the womb. There does not seem to be a difference between groups in maternal satisfaction, and there is no evidence on the effects of TXA on breastfeeding.

What are the limitations of the evidence?

Most studies included women at low risk of heavy bleeding after birth, preventing any conclusions about women at high risk of heavy bleeding after birth. Across trials, few women experienced harmful effects; however, we cannot be certain that this is the case in the real world.

What does this mean?

We found little to no difference in the number of women experiencing heavy bleeding after birth after they were given TXA preventatively during caesarean birth, and we are very uncertain about the effect of TXA on death, blood clots, and surgical removal of the womb. As these are harmful effects, health providers should take the benefit and the potential harms into account when considering routine treatment with TXA of women during caesarean birth.

There does not seem to be a difference in the number of women needing additional treatment for heavy bleeding after receiving TXA.

Giving every women who gives caesarean birth TXA preventatively during birth is a serious decision with many implications. We need to weigh up blood loss outcomes, as well as the relatively low rates of serious illness after postpartum haemorrhage and uncertainty regarding serious unwanted effects.

How up-to-date is this evidence?

The evidence is current to 20 February 2024.