Onset of the preovulatory luteinizing hormone surge: diurnal timing and critical follicular prerequisites

David J Cahill, Cahill DJ, D J Cahill, Wardle PG, Peter G. Wardle, P G Wardle, Christopher R. Harlow, C R Harlow, Harlow CR, Hull MG, M G Hull, M.G.R. Hull
Fertility and Sterility · 1998 · vol. 70(1) , pp. 56–59 · doi:10.1016/s0015-0282(98)00113-7 · PMID:9660421 · W2008625611
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This study investigates the diurnal timing and essential follicular conditions required for the initiation of the preovulatory luteinizing hormone surge.

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Abstract

ObjectiveTo determine the diurnal variation in the onset of the preovulatory LH surge in women.DesignProspective open cohort study.SettingUniversity hospital research program.Patient(s)Thirty-five women with infertility resulting from tubal damage that was associated with minor endometriosis or with infertility of prolonged unexplained etiology.Intervention(s)Women underwent transvaginal ultrasonography and serum E2 estimation daily during monitored cycles before unstimulated natural cycle IVF: exogenous gonadotropins were not administered.Main outcome measure(s)Serum E2 concentration, follicle diameter, and endometrial thickness.ResultsOf 169 cycles. 155 progressed to an ovulatory LH surge, of which 146 occurred within 8 hours of assessment of the outcome measures. The relationship between follicle diameter and E2 was weak, but an abnormal value for one always was countered by a normal value for the other.ConclusionsMost women begin the preovulatory LH surge between midnight and 8:00 A.M., but with no particular variation by day of the week. The relationship between follicle size and serum E2 is not sufficiently strong to predict the LH surge confidently on the basis of only one variable, but the LH surge is unlikely to occur before either the follicle diameter has reached 15 mm and/or the serum E2 level has reached 600 pmol/L.

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MeSH descriptors

Circadian Rhythm Luteinizing Hormone Ovarian Follicle Ovulation Adult Circadian Rhythm Coitus Coitus Endometrium Endometrium Endometrium Estradiol Estradiol Female Humans Infertility, Female Infertility, Female Infertility, Female Luteinizing Hormone Ovarian Follicle

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