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At least 19 recordsLinked to original sources
PubMed1981

Overview of the biological aspects of the fertile period.

The fertile period of the human menstrual cycle consists of those days on which sexual intercourse can result in a pregnancy. Its duration is determined by the functional life span of the gametes within the female reproductive tract. Various mechanisms control gamete transport and survival in the reproductive tract of the human female. The ovarian hormones estradiol and progesterone have an important role in regulating these mechanisms. The nature of cervical mucus and its governing influences on sperm transport and survival following coitus are of prime importance in defining the fertile days of the menstrual cycle. Man's early concepts of the fertile period were often based on erroneous theories of the female reproductive cycle. It is only since the late 1920's that a true understanding of ovulation and the menstrual cycle has evolved. Current approaches in natural family planning to recognizing the fertile and infertile days of the menstrual cycle are discussed and evaluated.

Cervix Mucus↗
PubMed1985

A prospective multicentre study to develop universal immunochemical tests for predicting the fertile period in women. World Health Organisation Task Force on Methods for the Determination of the Fertile Period, Special Programme of Research, Development and Research Training in Human Reproduction.

Two immunochemical tests for predicting the fertile period have been adapted for application throughout the world. The estrone test involves the measurement of estrone-3-glucuronide (E1-3-G) in daily samples of early morning urine. The start of the fertile period is identified by a sustained rise in the concentration of E1-3-G (as determined by cumulative sum analysis); the end of potential fertility occurs 120 hours (5 days) after the peak level. Alternatively, the ratio of E1-3-G to pregnanediol-3 alpha-glucuronide (Pd-3 alpha-G) can be calculated and the fertile period identified between a defined rise in this index and the peak value plus 144 hours (6 days). One hundred thirty-one women from 10 countries provided samples from 557 menstrual cycles, and the results from 455 (82%) were accepted for statistical analysis. There were highly significant differences (P less than 0.0001) in the concentrations of the metabolites between centres, but the time intervals between both the rise and peak days and the day of the luteinizing hormone (LH) peak were less significantly different (P less than 0.05) for the estrone test and not significantly different for the ratio test. The fertile period was defined as the day of the LH peak -3 to the day of the LH peak +2. The estrone test successfully delineated this phase in 78% of menstrual cycles, and the ratio test, in 74%. The mean lengths of the derived fertile periods by both methods were 9.3 (SD 2.3) and 10.0 (SD 2.4) 24-hour periods (or days), respectively.

Adult↗
PubMed1982

The measurement of urinary steroid glucuronides as indices of the fertile period in women. World Health Organization, Task Force on Methods for the Determination of the Fertile Period, special programme of research, development and research training in human reproduction.

The concentrations of various estrogen glucuronides and pregnanediol-3 alpha-glucuronide have been measured in daily samples of early morning urine (EMU) and 24 h pooled collections throughout a total of 70 menstrual cycles (58 subjects). The immediate objective was to identify and assess the potential value of measuring hormone metabolites to locate the fertile period in women, with the ultimate aim of developing a non-invasive immunochemical test. The project was undertaken in five centres and the results showed that: (i) there was good agreement in the patterns and mean concentrations of metabolites between the centres; (ii) estrone-3-glucuronide should be the estrogen glucuronide selected for further study; (iii) the analysis of EMU provided information that was as useful as the corresponding measurements on pooled collections for 24 h; (iv) a rise in the concentration of estrone-3-glucuronide (50% over the mean of three preceding values) could be used to locate the start of the fertile period in greater than 90% of the ovarian cycles (from day LHmax -- 3 to day LHmax -- 7); attempts to locate the end of the fertile period by a threshold value or a defined rise in the level of pregnanediol-3 alpha-glucuronide were disappointing. A 50% rise over the mean of three preceding values in the derived concentration ratio of estrone-3-glucuronide/pregnanediol-3 alpha-glucuronide could be used to indicate the start of the fertile period, and a 50% decrease plus two days the start of the infertile period in greater than 80% of the ovarian cycles. The limitations, implications and future developments are discussed.

Adolescent↗
PubMed1998

Definition of the potentially fertile period from urinary steroid excretion rates. Part II. A threshold value for pregnanediol glucuronide as a marker for the end of the potentially fertile period in the human menstrual cycle.

Application of time series analysis to a database containing serial pregnanediol data from 113 complete ovulatory menstrual cycles contributed by 83 women of proven fertility and 68 cycles for which pregnanediol values were available over the ovulatory period, detected the first statistically significant risk in pregnanediol excretion for all cycles for which a baseline was available (n = 170). However, even at the 99% confidence level, for 22% of cycles a rise was observed before the presumed day of ovulation. Therefore, a threshold value for pregnanediol was sought from the database as a better marker for the end of fertility. A value of 1.4 mg per 24 h was not reached before day 2 after the pre-ovulatory estrogen peak day for 96% of the cycles. In the remaining 4% of cycles it was reached one day after the total estrogen peak day. The validity of this threshold was confirmed in extensive studies using the Ovarian Monitor where the equivalent is 6.3 mumol per 24 h of pregnanediol glucuronide and measurements are performed on timed urine specimens with a minimum collection time of three hours. These studies were as follows: 1) a World Health Organization study on the use of the Ovarian Monitor as a fertility self test in the home (108 cycles), 2) a multicenter study on returning fertility during breast feeding conducted by Family Health International (73 women), and 3) the general application of the Ovarian Monitor for pregnancy achievement and avoidance during the past ten years (over 250,000 PdG assays performed in ten countries). With rare exceptions, the use of these threshold values is applicable for all women provided correction is made for urine volume.

Biomarkers↗
PubMed1983

Temporal relationships between indices of the fertile period.

The intra- and interwoman variation in nine physiologic or biochemical indices of the fertile period has been studied over 58 menstrual cycles from 13 experienced users of the symptothermal method of family planning by periodic abstinence. The time and duration of a possible fertile period have been determined by five methods (symptothermal, cervical mucus, basal body temperature plus calendar calculation, defined changes in the concentration of estrone-3-glucuronide and the ratio of estrone-3-glucuronide to pregnanediol-3 alpha-glucuronide as determined by immunochemical tests on daily samples of early morning urine). The values were compared with a period of probable fertility (day of urinary luteotropin [LH] peak -3 to day of LH peak +2). The duration of the possible fertile period by each method (mean +/- standard deviation) was 13.4 (2.9), 11.9 (2.9), 11.8 (3.3), 9.3 (2.2), and 10.9 (2.3) days, respectively, while the percentage of the probable fertile periods covered entirely by each approach was 98%, 91%, 90%, 83%, and 84%, respectively. The results warrant the initiation of clinical trials to ascertain the practical value of the individual or combined tests for family planning and the management of infertility.

Adult↗
PubMedDate not supplied

Prediction and detection of the fertile period: the markers.

The occurrence and duration of the fertile period in women are strictly related to the time of ovulation. Since the only positive confirmation of ovulation is the identification of an ovum in the female reproductive tract or the subsequent detection of a pregnancy, the prediction and detection of its occurrence have to be based on markers or indicators that lie at varying physiological distances from ovulation itself. These may be variations in hormones and other substances that can be detected in different body fluids or the evidence of their effects on specific target organs. Recent advances in the knowledge of reproductive physiology have allowed the identification of distinct substances and biological phenomena that accompany the occurrence of the fertile period. This article is intended to update and classify the available fertility markers based on their particular nature and modality of expression and, additionally, consider the temporal relationship between the appearance of their specific signals and the time of ovulation. Consequently, those indicators directly related to changes at the ovarian level were defined as direct markers, including ovarian morphology, the reproductive hormones, and the intraovarian regulatory proteins, whereas those reflecting variations observed in different target organs were considered indirect markers, and were further qualified as biochemical, biophysical, and clinical. Subsequently, fertility markers were classified as prospective, immediate, or retrospective, depending on whether they allow the prediction, detection, or confirmation of the ovulatory event, respectively.

Biomarkers↗
PubMed1994

Excretory profile of inhibin-like peptide (ILP) during human menstrual cycle: a probable marker for determination of fertile period.

The excretory profile of inhibin-like peptide (10.4 kDa) and its interrelationship with urinary LH, FSH, oestrone glucuronide (E1G) and pregnanediol glucuronide (PdG) during the menstrual cycle were studied. These hormones/metabolites were estimated in daily early morning urine samples obtained from 20 regularly menstruating women. The data revealed that the excretory profile of inhibin-like peptide (ILP) follows a pattern similar to that of E1G. In 17 cycles, ILP peaked 3-4 days prior to the urinary LH peak. A value of 70 ng/mg creatinine (95th centile of ILP levels obtained between 2 and 4 days prior to urinary LH peak and also 5th centile of peak ILP levels) was considered as an indicator of the start of the fertile period. A value of PdG more than 2 micrograms/mg creatinine on two consecutive days was considered as an end of the fertile period. The entire fertile period could be determined in 18 out 20 cycles when criteria based on ILP and PdG levels were applied (accuracy, 90%), whereas it could be determined in 13 out of 20 cycles when criteria based on E1G and PdG levels were applied (accuracy, 65%). Thus, ILP levels in urine may prove to be one of the signals for determining the start of fertile period.

Adult↗
PubMed1996

A comparison of the ovulation method with the CUE ovulation predictor in determining the fertile period.

The purpose of this study was to compare the CUE Ovulation Predictor with the ovulation method in determining the fertile period. Eleven regularly ovulating women measured their salivary and vaginal electrical resistance (ER) with the CUE, observed their cervical-vaginal mucus, and measured their urine for a luteinizing hormone (LH) surge on a daily basis. Data from 21 menstrual cycles showed no statistical difference (T = 0.33, p = 0.63) between the CUE fertile period, which ranged from 5 to 10 days (mean = 6.7 days, SD = 1.6), and the fertile period of the ovulation method, which ranged from 4 to 9 days (mean = 6.5 days, SD = 2.0). The CUE has potential as an adjunctive device in the learning and use of natural family planning methods.

Adult↗
PubMed1982

A statistical approach to the determination of the fertile period.

17 beta-Estradiol (E2), basal body temperature (BBT) and luteinizing hormone (LH), were measured in normally menstruating women. The preovulatory E2 observations were characterized by variations about a constant level during the preovula-peak. The BBT observations typically varied about a constant level during the preovulatory phase then about a higher constant level during the postovulatory phase. The change points in E2 and BBT were detected using a Bayesian detection rule and a midcycle 'fertile period' was marked off. The midcycle 'fertile periods' appear to bracket the ovulation event and the method shows promise as a natural family planning method. Several practical limitations of the method are discussed.

Bayes Theorem↗
PubMed1987

Regulation of the length of the fertile period in the domestic fowl by numbers of oviducal spermatozoa, as reflected by those trapped in laid eggs.

The numbers of spermatozoa trapped in the vitelline membrane of laid eggs were counted after staining with the fluorochrome 2,4-diamidino-2-phenylindole. In a group of 24 hens inseminated with different numbers of spermatozoa to produce different lengths of fertile periods, the numbers of spermatozoa in successive eggs from each hen decreased logarithmically with respect to days following insemination. A relationship could be described between the numbers of spermatozoa per unit area of membrane of an egg and the probability of that egg being fertile. After insemination the number of spermatozoa on successively-laid eggs appears to become reduced until a critical value is reached, after which the hen will lay infertile eggs. By estimating the day on which the critical value was achieved, the actual length of the fertile period could be predicted. It is suggested that the numbers of spermatozoa trapped in the vitelline membrane of laid eggs represent those which surround the ovum at the time of fertilization.

Animals↗
PubMedDate not supplied

[Concise measures of period fertility by birth order. An application to Italian data].

"In recent studies several authors have shown how fertility tables and concise measures by birth order, strictly and exclusively related to the period fertility conditions, can be derived on the basis of parity progression rates.... The many indicators derivable from the fertility tables compiled as stated above are described systematically and completely in relation to their different features. On the basis of a 'complementary' model [I show] a further category of concise measures referring to fertility tables which are formally identical to the classical life tables with regard to each order of birth. The study includes applications to concrete data concerning North Central and Southern divisions of Italy (1980-1982 and 1988-1990)." (SUMMARY IN ENG AND FRE)

Birth Order↗
PubMed1997

Transvaginal color flow imaging of the uterine artery during fertile period and postmenopause.

Transvaginal sonography with color flow mapping has been used in order to study various parts of uterine circulation during fertile period and postmenopause. The Doppler wave forms were analysed by pulsatility index and maximum systolic velocity of uterine artery and its ascending branches. A significantly lower vascular resistance was established in distal parts of the uterine artery. This finding could very likely represent a consequence of the effect of ovarian hormones on the vessel wall during the cycle. That might be a physiological basis for capability of fertilisation and carrying the normal pregnancy and child birth. Furthermore, it has been shown that during postmenopause, when ovaries normally cease steroid hormone production, it is difficult to detect wave forms in common uterine artery. However, postmenopausal extraovarian production of estrogen increases uterine flow and may precede hyperplastic or malignant changes of the endometrium. In women with proven pelvic masses, abnormal waveforms were recorded showing decreased uterine impedance and increased flow velocities.

Adult↗