Do Women Who Had Tonsillitis or Appendicitis in Their Youth Have Higher Pregnancy Rates?

In a large-scale population-based cohort study, researchers from the University of Dundee, in collaboration with University College London, investigated the association between certain surgical procedures in childhood and adolescence and the subsequent fertility of women. The study focused on appendectomy (removal of the appendix) and tonsillectomy (removal of the tonsils), two routine medical procedures that have occasionally been attributed with a potentially negative impact on reproductive health in the past. The aim of the study was to empirically test this assumption using extensive long-term data.

How Appendectomy or Tonsillectomy Affect Pregnancy Rates

The analysis was based on anonymized health data from over 500,000 women in the UK who were observed over several decades. The women were divided into four groups: a control group without surgery, a group that had undergone appendectomy, a group that had undergone tonsillectomy, and a group that had undergone both procedures. The primary endpoint was defined as the first occurrence of pregnancy. In addition, the time to first pregnancy was analyzed. Cox regression models were used for statistical analysis, taking into account possible confounding factors such as age, socioeconomic status, and relevant pre-existing conditions.

The results showed that women who had undergone an appendectomy or tonsillectomy were significantly more likely to have at least one pregnancy than women who had not undergone these procedures. While approximately 44% of women in the control group became pregnant, this proportion was around 54% for women who had undergone an appendectomy and approximately 53% for women who had undergone a tonsillectomy. The highest pregnancy rate was observed in women who had undergone both procedures, at just under 60%. In addition, these women became pregnant faster on average than women without a history of such surgery. The statistical models indicated an increased likelihood of pregnancy, even after adjusting for known influencing factors.

Despite these clear associations, the authors expressly emphasize that the results do not prove a causal relationship. This means that it cannot be assumed that the removal of tonsils or the appendix directly leads to increased fertility. Rather, several possible explanations are discussed. One central hypothesis concerns so-called confounders, in particular behavioral factors: women with higher social activity or more frequent sexual contact may have both a higher risk of certain childhood infections and a higher probability of later pregnancies. Another explanation could be increased medical monitoring of these women, as they had more frequent contact with the healthcare system.

In addition, a possible immunological connection is discussed. Both the tonsils and the appendix are part of the lymphatic system and play a role in immune defense. There is speculation as to whether changes in the immune system after their removal could indirectly influence processes relevant to implantation or the course of pregnancy. However, there is currently insufficient experimental or clinical evidence to support this assumption, which is why it is explicitly classified as hypothetical.

Interpreting the Results Correctly

The central conclusion of the study is therefore not so much the assumption of a fertility-enhancing effect, but rather the refutation of a long-standing medical prejudice. The data clearly show that neither appendectomy nor tonsillectomy is associated with reduced fertility. Rather, these procedures do not appear to have a negative impact on the likelihood of subsequent pregnancy. The researchers expressly warn against interpreting the results as justification for prophylactic or deliberately induced surgical procedures. The scientific and clinical added value of the study lies primarily in giving affected women a well-founded all-clear and dispelling unfounded concerns about the possible long-term effects of such operations.