%0 Journal Article
%T The definition of unexplained infertility: A systematic review.
%A Raperport C
%A Desai J
%A Qureshi D
%A Rustin E
%A Balaji A
%A Chronopoulou E
%A Homburg R
%A Khan KS
%A Bhide P
%J BJOG
%V 131
%N 7
%D 2024 Jun 13
%M 37957032
%F 7.331
%R 10.1111/1471-0528.17697
%X <B>BACKGROUND: </B>There is no consensus on tests required to either diagnose unexplained infertility or use for research inclusion criteria. This leads to heterogeneity and bias affecting meta-analysis and best practice advice.<BR><B>OBJECTIVE: </B>This systematic review analyses the variability of inclusion criteria applied to couples with unexplained infertility. We propose standardised criteria for use both in future research studies and clinical diagnosis.<BR><B>METHODS: </B>CINAHL and MEDLINE online databases were searched up to November 2022 for all published studies recruiting couples with unexplained infertility, available in full text in the English language.<BR><B>METHODS: </B>Data were collected in an Excel spreadsheet. Results were analysed per category and methodology or reference range.<BR><B>RESULTS: </B>Of 375 relevant studies, only 258 defined their inclusion criteria. The most commonly applied inclusion criteria were semen analysis, tubal patency and assessment of ovulation in 220 (85%), 232 (90%), 205 (79.5%) respectively. Only 87/220 (39.5%) studies reporting semen analysis used the World Health Organization (WHO) limits. Tubal patency was accepted if bilateral in 145/232 (62.5%) and if unilateral in 24/232 (10.3%). Ovulation was assessed using mid-luteal serum progesterone in 115/205 (56.1%) and by a history of regular cycles in 87/205 (42.4%). Other criteria, including uterine cavity assessment and hormone profile, were applied in less than 50% of included studies.<BR><B>CONCLUSIONS: </B>This review highlights the heterogeneity among studied populations with unexplained infertility. Development and application of internationally accepted criteria will improve the quality of research and future clinical care.