First pregnancies complicated by postpartum haemorrhage (PPH) have no detrimental effect on future fertility but women who have caesarean sections at the time of PPH are less likely to conceive again, finds a new study published in BJOG: An International Journal of Obstetrics and Gynaecology.

There has been a rise in the overall rate of PPH (where blood loss is >500ml) in the UK, due to increases in maternal risk factors and in the number of caesarean sections performed. Women who undergo caesarean section deliveries are more likely to suffer PPH than vaginal deliveries (59% vs 21%).

This study, conducted at the Aberdeen Maternity Hospital in Scotland over a 20-year period (1986-2005), using information from the Aberdeen Maternity and Neonatal Databank looked at 34,334 first pregnancies and found that 10% experienced PPH.

The paper identified increased maternal age, high BMI readings and smoking as contributing risk factors to the likelihood of experiencing PPH.

After their first pregnancy, the women were monitored for a minimum of five years to identify a second pregnancy. Women who had experienced PPH in their first pregnancy were then compared to women who did not.

Researchers found that there were no significant differences between those who experienced PPH and those who did not for the proportion of women who went on to conceive a second pregnancy, in the time interval between pregnancies or in early/late pregnancy loss.

However, mode of delivery among women who had initially experienced PPH was a significant factor in the likelihood of a second pregnancy. Of the women who initially had a caesarean section that was complicated by PPH, 41.5% did not conceive a second pregnancy compared to 36.8% of women who had a caesarean section that was not complicated by PPH.

The paper also found that women who were initially exposed to PPH showed a high recurrence rate and were 2.9 times more likely to experience PPH during their second pregnancy than those who had no initial exposure (18% vs 6.9%).

Gail Fullerton from the Aberdeen Maternity Hospital, and co-author of the study, said:

"While experiencing PPH in an initial pregnancy increases the risk of recurrence in subsequent pregnancies, it should not be cause for concern in relation to future fertility.

"The women in our study showed no adverse affects to the likelihood or timing of future pregnancies after an initial PPH complication.

"However, it is clear that more research needs to be done to ascertain why there is a significant decrease in a subsequent pregnancy following PPH at time of an initial c-section delivery."

John Thorp, BJOG Deputy-Editor-in-Chief, added: "While PPH remains a major cause of maternal morbidity and mortality around the world, there have been improved changes to obstetric practice in the UK over the past decade in relation to management and treatment, leading to a reduction in the rates of adverse outcomes such as hysterectomy.

"PPH is a very traumatic experience for women and this study is reassuring in its findings that there is no overall reduction in the numbers returning for a second pregnancy following an initial PPH complication.

"Any women who harbour concerns after experiencing PPH should consult their obstetrician about the mode of delivery and management of any subsequent pregnancies."