Elizabeth A. Lenton

Normal variation in the length of the luteal phase of the menstrual cycle: identification of the short luteal phase

Normal probability plots were used to assess the homogeneity of a population of 327 luteal phases from apparently ovulatory menstrual cycles. The length of the luteal phase was defined as the interval (in days) following but not including, the luteinizing hormone peak, up to and including the day before onset of menstruation. A small sub‐set of the population consisted of cycles with abnormally short luteal phases but the majority of the data followed a normal frequency distribution which gave a mean (± SD) for normal luteal phase length of 14.13 (± 1.41) days. It was estimated that all cycles with a luteal phase 9 days were abnormal, and that 74%, 22% and 2% respectively of cycles with luteal phases of 10, 11 and 12 days were also abnormal. The total incidence of short luteal phases defined as above was 5.2%.

Normal variation in the length of the follicular phase of the menstrual cycle: effect of chronological age

Normal probability plots were used to analyse the distribution of follicular phase length in a population of 293 apparently ovulatory menstrual cycles from women aged between 18 and 39 years. The length of the follicular phase was defined as the interval (in days) from the onset of menstruation up to, but not including, the day of the LH peak. Follicular phase length appeared to be log‐normally distributed and graphical inspection of the probability plot suggested that the geometric mean (and 95% confidence limits) of follicular phase length in this study group was 12–9 (10–3 to 16–3) days. There was a significant decrease (P<0.001) in follicular phase length with chronological age, from 14–2 days in women aged 18–24 years to 10.4 days in women aged 40–44 years.

Hypothalamic‐pituitary ageing: progressive increase in FSH and LH concentrations throughout the reproductive life in regularly menstruating women

OBJECTIVE Reproductive ageing is associated with reduced fertility and endocrine changes that become more pronounced during the perimenopausal period. We aimed to assess changes in gonadotrophin concentrations and the onset of these changes during the reproductive life prior to the perimenopause.

Follicle growth patterns and endocrinological abnormalities in infertile women with minor degrees of endometriosis

Summary. Eighteen patients whose only demonstrable cause of infertility was a minor degree of endometriosis and whose partners were normal, were investigated prospectively for one menstrual cycle using ultrasonography and endocrine profiles. Twelve cycles appeared to be normal. A luteinized unruptured follicle (LUF) occurred in two cycles and one patient had a follicular cyst. In a further two patients there was inadequate or abnormal folliculogenesis whilst in the last patient the follicle ruptured prematurely. This study describes the variety of endocrinological abnormalities found in women with mild endometriosis, and concludes that, in this series at least, there is a low frequency of LUF.

The variation of endometrial response to a standard hormone replacement therapy in women with premature ovarian failure. An ultrasonographic and histological study

Summary. The endometrial response to a standard hormone replacement therapy in 18 women with premature ovarian failure was examined by serial ultrasonographic measurement of endometrial thickness and histological study of endometrial biopsy taken on day 19 of the cycle. Women with idiopathic ovarian failure (n = 10) had significantly better response than women with Turners syndrome (n = 4), whereas women with premature ovarian failure associated with previous chemotherapy (n = 4) had an intermediate response. These observations suggest that the endometria of women with Turners syndrome responded suboptimally to steroid hormones. However, all endometrial biopsies studied revealed secretory changes. Overall, the results of histological dating of endometrial biopsy were found to be positively correlated with endometrial thickness on day 19 of the cycle (r = 0.72, P < 0.01). The plasma concentration of oestradiol on days 15, 19 and 29 of the artificial cycle were found to be significantly higher than those on the corresponding days of the natural cycle.

PROLACTIN CONCENTRATIONS IN NORMAL MENSTRUAL CYCLES AND CONCEPTION CYCLES

Plasma prolactin concentrations were measured daily throughout twenty‐three menstrual cycles from regularly ovulating women. In five of the cycles conception occurred spontaneously. The frequency distribution of prolactin concentrations was calculated and an appropriate linear transform obtained. Means and 95% confidence limits were determined by inspection of the logarithmic probability plots and these gave mean concentrations (and ranges) of 302 (106–871) mU/1 for the non‐conception cycles and 178 (58–550) mU/1 for the conception cycles. Distribution of prolactin concentrations was log‐normal in all cases, although the population containing the conception cycles was distinct from the population of non‐conception cycles. It is suggested that the normal range found in ovulating women is 80–800 mU/1 but that for conception to occur levels should be slightly lower and approximate to the range 60–600 mU/1. Thus the lower limit of normal is about 60 mU/1 and the upper limit about 800 mU/1. Any concentration over 800 mU/1 should be designated as hyperprolactinaemia.

Suppression of gonadotrophin secretion does not reverse premature ovarian failure

Summary. The effect of prolonged inhibition of gonadotrophin secretion was studied in 12 women with premature ovarian failure. All the patients had plasma concentrations of follicle‐stimulating hormone (FSH) >20 i.u./l, and in six, primordial follicles had been seen on ovarian biopsy. Goserelin (Zoladex, ICI), a depot synthetic analogue of luteinizing hormone‐releasing hormone (LHRH) was administered by three consecutive 4‐weekly injections. Plasma concentrations of luteinizing hormone (LH) fell from 34 (SD ll) i.u./l to 2·4 (SD 1·9)i.u./l, and plasma concentrations of FSH fell from 106 (SD29) i.u./l to 4·5 (SD 2·6) i.u./l 4 weeks after the first injection. Plasma concentrations of gonadotrophins returned to pretreatment values in every patient within 9 weeks of the final injection of goserelin. Regular ultrasonography during the period following the final injection failed to demonstrate the development of ovarian follicles in any patient, and plasma concentrations of oestradiol remained below 100 pmol/l. This study has failed to show that suppression of gonadotrophin secretion reverses premature ovarian failure.

Cost-effectiveness analysis of different embryo transfer strategies in England

Objective  The objective of this study was to assess the cost‐effectiveness of different embryo transfer strategies for a single cycle when two embryos are available, and taking the NHS cost perspective.

The short luteal phase and infertility

Summary. The distribution of the length of the luteal phase was investigated in 187 women with regular, apparently ovulatory menstrual cycles of whom 95 had unexplained infertility and the other 92 comprised a group of healthy volunteer subjects. If the short luteal phase is associated with infertility it might be expected t o occur more frequently in women with unexplained infertility. A short luteal phase (defined as a luteal phase lasting ≤ 11 days) was found in 9% of the infertile group and in 8% of the normal group showing that these cycles do not occur more frequently in women with infertility.

OESTRADIOL SECRETION IN MEN AND PRE-MENOPAUSAL WOMEN

Blood samples were obtained from a group of regularlycycling normal women (n = 13) and a group of normal men (n= 5) at 15 min intervals for periods ranging from 9–14 h whilst the subjects remained resting quietly in bed. The concentration of plasma oestradiol was measured in a radioimmunoassay which had been carefully optirnised and the mean concentration and coefficient of variation calculated for each subject.