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Results for “Fertility Measurements”

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At least 19 recordsLinked to original sources
PubMed2002

The effect of changes in timing of childbearing on measuring fertility in England and Wales.

Changes in the ages at which women give birth to their children mean that fertility measured at a particular point in time (period) may not be a good representation of the ultimate fertility of those women. The common measure of period fertility is the total fertility rate, which in 2001 has fallen to the lowest level since records began in England and Wales. This article presents various methods that have been proposed to adjust period fertility data to take account of changes in the timing of childbearing, applied to England and Wales data. The article concludes that while these adjustment methods provide useful insights, for example, that the total fertility rate has underestimated period quantum fertility since the 1970s, the measures produced are difficult to interpret. This is in part because the concept they are trying to measure, period quantum is itself imprecise. The adjustments do not necessarily provide a reliable indicator of underlying cohort fertility.

Adolescent↗
PubMedDate not supplied

Individual fertility rate: a new individual fertility measure for small populations.

Fertility measurement in small preindustrial societies is hampered by small numbers and the lack of some essential data. Most measures of fertility are collective and require large enough populations to permit grouped data analysis. Existing individual measures of fertility are often unsatisfactory. This paper presents a new measure of individual fertility, the Individual Fertility Rate (IFR), which is constructed by dividing parity by reproductive span in years and multiplying the product by 100. The result is a number which may be used as a dependent individual or cumulative variable to study the effects of health and socioeconomic factors on fertility.

Adult↗
PubMedDate not supplied

[A comparison of complete and truncated birth histories to measure fertility and child mortality].

"During the latter part of 1986, national probability sample surveys of women of reproductive ages were carried out in... Peru and the Dominican Republic. These surveys were made as part of the Demographic Health Surveys project (DHS). In each country, one survey was conducted with the standard core questionnaire developed for DHS; the other survey was based on an experimental questionnaire. The major difference between the two questionnaires is the inclusion in the experimental one of a monthly calendar, which records pregnancies, contraceptive use, reasons for contraceptive discontinuation, breastfeeding, post-partum amenorrhea, post-partum abstinence, women's employment and place of residence for the period 1981-1986. This paper presents results from the first stage of the analysis of the Peruvian data: a comparison of basic characteristics of the two samples and an assessment of the completeness of reporting of recent births and infant and child deaths, i.e., a comparison of information in the truncated and full birth histories." (SUMMARY IN ENG)

Americas↗
PubMed2001

Relationship of somatic cell score with fertility measures.

Dairy Herd Improvement data from 284,450 cows in 37 states were used to examine the relationship of test-day somatic cell score, herd, calving year, parity, lactation stage, and calving ease score with fertility measures (rate of nonreturn to estrus by 70 d after first service, days to first service, and days open) for US Holsteins and Jerseys. Factors other than somatic cell score were examined to ensure that the estimation of the effect of somatic cell score was independent of other effects. Nonreturn rates were highest during April and May and lowest during June. Parity had a large effect on nonreturn rate, which was 6 to 7% higher for first parity than for sixth parity and later. Effect of lactation stage at first service on nonreturn rate was large; nonreturn rate increased by 8 to 13% from early to late lactation. Effect of calving ease score on nonreturn rate also was large: a 7% decline in nonreturn rate from score 1 to 5. For Holsteins, a small linear regression was found for nonreturn rate on preceding test-day somatic cell score, but this relationship was not significant for Jerseys. The magnitude of the effect of somatic cell score on fertility traits does not warrant postponing first service when somatic cell score is high.

Animals↗
PubMed1991

[[The tempo and quantum components in trends in period fertility measures in present-day Japan: a Butz-Ward-type model and its application]].

"This paper examined the validity of a Butz-Ward-type model by applying it to trends in Japan's fertility rates from 1968 to 1986. Most of the existing studies on the Butz-Ward model used total fertility rates as the dependent variable. As the Butz-Ward model is concerned with couples' fertility behaviors, [the author uses]...total marital fertility rates. We first calculated total marital fertility rates (TMFR) from 1968 to 1986 by using data of Japan's National Fertility Surveys.... As a result of the auto-regression analysis of TMFR, we found a statistically significant negative effect of a rise in employed wife's wage rate as was expected. As for the timing indices, the third birth timing index was significantly positively affected by an increase in husband's income when his wife was employed, while the third birth was likely to be delayed by a rise in employed wife's wage rate." An English summary is available from the author.

Asia↗
PubMed1995

Measuring fertility demand.

We propose a multidimensional conceptualization of fertility demand and evaluate potential measures of each dimension, using data from a telephone survey of Wisconsin residents age 18-34. Most of the measures met tests for interval-level measurement; all produced high estimates of test-retest reliability. We found support for only two dimensions of demand, intensity and certainty; potential measures of centrality had relatively low associations with any of the latent dimensions. Demand certainty improved prediction of fertility expectations beyond a trichotomous (yes, no, don't know) measure, but demand intensity did not. We found mixed evidence for the conceptualization of fertility demand as a single continuum on which desire to avoid pregnancy is the opposite of desire to have a child.

Adolescent↗
PubMed1997

Fertility measures in women after extracorporeal shockwave lithotripsy of distal ureteral stones.

Long-term effects of extracorporeal shockwave lithotripsy (SWL) on female fertility remain a concern. Thirty-nine women of childbearing age who were treated for distal ureteral stones were surveyed. The mean age of these women was 33 years, and the average stone size was 6.9 mm. The mean calculated radiation exposure to the ovaries and the uterus was 7.53 and 10.9 mSv, respectively. Ten women (26%) attempted to become pregnant. No fertility problems were noted in these women, and 11 healthy babies were delivered. These preliminary findings provide further information regarding the safety of SWL in the treatment of distal ureteral stones in women of reproductive age.

Adolescent↗