Having given birth recently appears to be a protective factor against endometrial cancer (EC), according to a recently published study in PLOS ONE.
“Women who are older at their final birth may have reduced endometrial cancer risk, as sustaining pregnancy later in life may indicate a healthier endometrial environment or fewer anovulatory cycles,” the authors wrote.
Due to the benefits associated with early diagnosis and treatment for patients with EC, there is growing interest in detecting risk factors that can guide prevention. So far, risk factors such as polycystic ovarian syndrome, infertility, family history, obesity and diabetes have been identified and are well documented. However, the effect of pregnancy on the disease remains unclear.
Some studies suggest that reduced estrogen exposure during pregnancy could have a beneficial effect in preventing EC. On the other hand, pregnancy-related factors such as placental growth factor (PlGF) and placenta-specific protein 1 (PLAC-1) might increase cancer risk.
To further clarify the effect of pregnancy, the authors conducted a meta-analysis on the subject. A meta-analysis combines the results of several studies on a given topic to obtain a pooled estimate of effect size and its precision. This meta-analysis included data from eight studies and 3,310,734 patients.
Seven of the included studies analyzed the correlation between 0 to 10 years since last birth and endometrial cancer. The results showed that a recent birth was associated with a significant reduction in EC risk. The study also included data on the correlation between a 10–20 year span since last birth and EC, observing that this group also had a decreased risk. However, a history of more than 20 years since the last birth was associated with an increased EC risk.
The authors noted that the included studies made statistical adjustments to ensure that age, a well-established risk factor for EC, did not interfere with the results.
“Shorter intervals since the last birth appear to offer protective benefits to the endometrial lining, while longer intervals in multiparous women significantly elevate risk,” the authors wrote.
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