Pregnancy complications more likely following assisted reproduction

Assisted reproduction is associated with an increased risk of vascular and other complications during pregnancy, especially in women with pre-existing health problems, a comparative study using hospital data from the USA has shown.

Whether or not fertility treatments are linked to any increased risk of adverse events during pregnancy and childbirth is not well understood (see BioNews 1128). This study published in the Journal of the American Heart Association has shown that women who conceived using assisted reproduction techniques are 2.5 times more like to experience kidney injury and incur hospital costs an average of US$6722 higher when hospitalised, compared to women who conceived naturally.

'We were surprised that assisted reproductive technology was independently associated with these complications, as opposed to being associated with only the existence of pre-existing health conditions or only among older women undergoing treatment,' said study author Dr Pensée Wu.

Researchers compared data on the outcomes of 106,248 deliveries conceived with assisted reproduction with 34.2 million deliveries without fertility treatment between 2008 and 2016 in the USA. The researchers found that women who conceived using assisted reproduction were an average of seven years older – 35 compared to 28. They also had more pre-existing health conditions, such as chronic high blood pressure, obesity and diabetes, this was despite being less than half as likely to smoke than women who had conceived naturally. They were more likely to be white and have higher incomes than women who conceived naturally.

Results of the study showed women who had undergone assisted reproduction had an adjusted risk of experiencing an irregular heartbeat during pregnancy that was 65 percent higher than women who had conceived naturally, and were 57 percent more likely to experienced placental abruption. There was also a 26 percent increased risk of premature delivery associated with assisted conception.

There was a 26 percent increased chance of multiple pregnancy in the assisted reproduction group, but no increased risk of placental abruption when compared to multiples who had been conceived naturally.

The higher risk for complications existed whether or not women had pre-existing cardiovascular risk factors, but was highest among those who did. However, the study authors did not directly compare different types of fertility treatment, a major limitation of the findings.

Researchers made a couple of suggestions behind what mechanisms could be behind these findings. Women who underwent assisted reproduction were more likely to have congenital heart disease, they found. They also propose the drugs used during IVF could affect hormone levels during the pregnancy and that ovarian hyperstimulation syndrome which is a risk associated with egg retrieval could affect clotting and fluid balance mechanisms.

'Especially those with existing cardiovascular risk factors should be counseled about the potentially long-term cardiovascular implications and risks associated with assisted reproductive technologies,' Dr Wu said. 'It's important for women to know that assisted reproductive technology carries a higher risk of pregnancy complications, which will require close monitoring, particularly during delivery. Primary and specialist health care professionals should ensure these risks are communicated and strategies to mitigate them are discussed and implemented.'