1,720,969 research outputs found
Colombo Bernardo. — Sul rapporto dei sessi nelle nascite e nei concepimenti
No full textCailar A. Colombo Bernardo. — Sul rapporto dei sessi nelle nascite e nei concepimenti. In: Population, 11ᵉ année, n°3, 1956. p. 566
Colombo Bernardo. — Sul rapporto dei sessi nelle nascite e nei concepimenti
No full textCailar A. Colombo Bernardo. — Sul rapporto dei sessi nelle nascite e nei concepimenti. In: Population, 11ᵉ année, n°3, 1956. p. 566
Calendar methods of fertility regulation: a rule of thumb
No full textSuppose that in each menstrual cycle a group of couples abstains for k days from intercourse, otherwise allowed in any other phase of the cycle. In a given cycle, the conception probability will depend on k, on the location within the cycle of the period of abstinence and on the pattern of intercourse episodes. An elaboration of this as-sumption on groups of cycles for which the relevant documentation is available gives idea of its consequences. For each group, under various conditions, an average concep-tion probability in a cycle is estimated. For that purpose, several hypotheses are made: about the size of k; about the location of the period of abstinence within the cycle; about frequency of intercourse outside that phase and the pattern of fecundability on different days of the menstrual cycle. Two fecundability models have been chosen from the literature and the calculations have been made on groups of cycles conveniently selected from a large data base of empirical observations. The results of the exercise give information of some relevance for fertility regulation through the use of calendar methods
Age and fertility: Can we wait until the early 30s?
No full textDelaying the start of childbearing raises the issue of fertility postponed versus fertility foregone. One of the limits of previous studies of "How late can you wait?" is the difficulty of controlling for sexual activity. Data on the frequency and timing of intercourse within a menstrual cycle are uncommon. We use such data from the Menstrual Cycle Fecundability Study to study "Can we wait until the early 30s?". We model the effect of age on conditional fecundability, i.e., the probability of conception given that the couple is not sterile, simultaneously controlling for the effect of primary sterility and the frequency and timing of intercourse in each menstrual cycle. Can we wait until the early 30s for a first birth? Our evidence is yes (providing you are not already sterile) as the increase in the mean waiting time to conception is very modest and of little practical importance
Cervical mucus secretions on the day of intercourse: An accurate marker of highly fertile days
No full textObjective: To provide estimates of the probabilities of conception according to vulvar mucus observations classified by the woman on the day of intercourse.
Study design: Prospective cohort study of 193 outwardly healthy Italian women using the Billings Ovulation Method. Outcome measures include 161 conception cycles and 2594 non-conception cycles with daily records of the type of mucus and the occurrences of sexual intercourse.
Results: The probability of conception ranged from 0.003 for days with no noticeable secretions to 0.29 for days with most fertile-type mucus detected by the woman. The probability of most fertile type mucus by day of the menstrual cycle increased from values <20% outside of days 10–17 to a peak of 59% on day 13.
Conclusion: Regardless of the timing of intercourse in the menstrual cycle, the probability of conception is essentially 0 on days with no secretions. This probability increases dramatically to near 30% on days with most fertile-type mucus, an association that accurately predicts both the timing of the fertile interval and the day-specific conception probabilities across the menstrual cycle
Spunti di ricerca biometrica sul ciclo mestruale
No full textIl lavoro contiene analisi statistiche sulla biometria del ciclo femminile a partire da una base di dati longitudinali derivanti da uno studio multicentrico
Cervical mucus symptom and daily fecundability: First results from a new data base
Get PDFA prospective study allowed, with the collaboration of Italian centres providing services on natural family planning, to collect data on 2755 menstrual cycles of 193 women. With the information available on daily characteristics of the cervical mucus and intercourse episodes, was constructed a data base. Taking the day of the peak mucus as a conventional marker of ovulation, the base allowed to identify length (12 days) and location of a window of potential fertility, with the highest level of conception probabilities confined to the central 5-6 days. Univariate analysis provided evidence of the impact on fecundability of woman?s age and basic infertile pattern of a cycle. Several approaches of analysis allowed to underline the relationship between daily mucus characteristics and fecundability levels
Cervical mucus symptom and daily fecundability: first results from a new database
No full textWith the collaboration of Italian centres providing services on natural family planning, a prospective study
collected data on 2755 menstrual cycles of 193 women. A database was constructed using information on
the daily characteristics of cervical mucus and episodes of intercourse. Taking the day of peak mucus as a
conventional marker of ovulation, the database identified the length (12 days) and location of a ‘window’
of potential fertility, the highest level of conception probability being confined to the central five to six
days. Univariate analysis provided evidence of the impact on fecundability of the woman’s age and the
basic infertile pattern of a cycle. Several analytical approaches highlighted the relationship between daily
mucus characteristics and levels of fecundabilit
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