Appendix and tonsil removals lead to higher pregnancy rates, study shows
Published On Tue 2 Aug 2016 by Roddy Isles
Women who have their appendix or tonsils removed when they are young are more likely to get pregnant, and do so sooner, than the rest of the population, a new study led by the University of Dundee has shown.
The study examined the anonymised medical records of hundreds of thousands of women in the United Kingdom. Pregnancy rates were significantly higher among those who had had an appendectomy (54.4%), tonsillectomy (53.4%) or both (59.7%) than those in the rest of the population (43.7%).
Time to pregnancy was also shortest among those who had both an appendectomy and tonsillectomy, followed by appendectomy only and then tonsillectomy only, compared with the rest of the population.
This new study, carried out at the University of Dundee and University College London, followed a 2012 report from the same research team which initially revealed the surprising statistics around appendectomies and pregnancy.
“For many years medical students were taught that appendectomy had a negative effect on fertility and young women often feared that having their appendix removed threatened their chances of later becoming pregnant,” said Sami Shimi, Clinical Senior Lecturer in the School of Medicine at the University of Dundee and a consultant surgeon with NHS Tayside.
“Our first study produced such a surprising result – that women who had had their appendix removed actually appeared more likely to become pregnant – that we wanted to look at a wider group to establish whether this was really related to the removal of the appendix, which if left can be a cause of inflammation.
“However, once again the results have been surprising. We have found that women who have had an appendectomy or tonsillectomy, or even more particularly both, are more likely to become pregnant, and sooner than the rest of the general population.
“This scientifically challenges the myth of the effect of appendectomy on fertility. What we have to establish now is exactly why that is the case.”
Dr Li Wei, of the School of Pharmacy at University College London, said, “This research is of paramount interest because appendectomy and tonsillectomy are very common surgical operations, experienced by tens of thousands of people in the UK alone.
“Although a biological cause is possible, we believe that the cause is more likely to be behavioural. We are pursuing both hypotheses with further research.”
Mr Shimi said that the findings should not be taken as a sign that women should seek an appendectomy or tonsillectomy thinking it would increase their chances of becoming pregnant.
“This research does not mean that removing a normal appendix directly increases fertility,” said Mr Shimi. “It does however mean that young women who need to have their appendix removed can do so without fear of the risk on future fertility.”
The researchers utilised the world’s largest digital repository of medical records from primary care, the UK Clinical Practice Research Databank. Their analysis included 54,675 appendectomy-only patients, 112,607 tonsillectomy patients, and 10,340 patients who had undergone both procedures. These were compared to the records of 355,244 women from the rest of the population, matched for age.
The results of the study are published in the journal of Fertility and Sterility. The paper can be viewed here: 10.1016/j.fertnstert.2016.06.022
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