Fig 1.
Consort-like flowchart of women in the third Nord Trøndelag Health Study (HUNT3, Norway) population-based cohort for assessment of the ovulation point prevalence.
† Indicates women excluded due to pregnancy, childbirth within the last year, hysterectomy with or without single or bilateral ovariectomy, probable menopause, or missing data.
Table 1.
Characteristics of 3,709 spontaneously menstruating* women ages 20–49.9 in the third Nord-Trøndelag Health Study (HUNT3), Norway reporting regular or irregular menstrual cycles in the last 12 months.
Fig 2.
Median serum progesterone levels in nmol/L across a studied menstrual cycle by cycle days in 3236 spontaneously menstruating premenopausal women aged 20–49.9 with regular cycles in HUNT3 (Norway) study.
Table 2.
Characteristics of 1545 spontaneously* normally menstruating premenopausal women who, by cycle days and usual cycle length (CL) were in the presumed luteal phase in HUNT3 (Norway) comparing those ovulatory by a serum progesterone threshold of ≥9.54 nmol/L with those without apparent ovulation.
Fig 3.
Bar graph of the 1545 women from the HUNT3 (Norway) ovulation study with progesterone levels during cycle days in the presumed luteal phase (cycle days 14 to -3 before usual cycle length) showing the percentage of women that were ovulatory using different threshold serum progesterone levels and by whether they reported the prescreening date menstrual flow started (LMP, cross-hatched bars, n = 1412) or were in a sub-cohort reporting both the LMP and post-screening menstrual flow dates (NMP, open bars, n = 133).
Differences between ovulatory percentages in the two cohorts were significant for progesterone thresholds of ≥3.5, ≥8.0 and ≥9.54 nmol/L.
Table 3.
Univariable and multivariable logistic regression of the likelihood of ovulation in spontaneously (without hormonal contraception) and regularly menstruating women aged 20–49.9 based on a serum progesterone level of ≥9.54 nmol/L in HUNT3 (Norway)#.