The association between prior appendectomy and/or tonsillectomy in women and subsequent pregnancy rate: a cohort study

OBJECTIVE: To study pregnancy rates after appendectomy and/or tonsillectomy.

DESIGN: Population-based cohort study using the United Kingdom (U.K.) primary health care-based Clinical Practice Research Datalink (CPRD).

SETTING: Not applicable.

PATIENT(S): Female patients who underwent appendectomy, tonsillectomy, or both from 1987 to 2012 and appropriate comparators.

INTERVENTION(S): Timed follow-up until first pregnancy after surgery. The association between prior surgery and subsequent pregnancy was determined with the use of Cox regression models.

MAIN OUTCOME MEASURE(S): Pregnancy rate and time to first pregnancy after surgery.

RESULT(S): The analyses included 54,675 appendectomy-only patients, 112,607 tonsillectomy-only patients, 10,340 patients who had both appendectomy and tonsillectomy, and 355,244 comparators matched for exact age and practice from the rest of female patients in the database. There were 29,732 (54.4%), 60,078 (53.4%), and 6,169 (59.7%) pregnancies in the appendectomy-only, tonsillectomy-only, and both appendectomy tonsillectomy cohorts, respectively versus 155,079 (43.7%) in the comparator cohort during a mean follow-up of 14.7 ± 9.7 years. Adjusted hazard ratios (HRs) for subsequent birth rates were 1.34 (95% confidence interval [CI] 1.32-1.35), 1.49 (95% CI 1.48-1.51), and 1.43 (95% CI 1.39-1.47), respectively. Time to pregnancy was shortest after both appendectomy and tonsillectomy followed by appendectomy only and then tonsillectomy only compared with the rest of the population.

CONCLUSION(S): Appendectomy and/or tonsillectomy was associated with increased subsequent pregnancy rates and shorter time to pregnancy. The effect of the surgical procedures on the pregnancy outcome was cumulative.