Accuracy of men's recall of their partner's time to pregnancy

Self-reported infertility among male and female veterans serving during Operation Enduring Freedom/Operation Iraqi Freedom

BACKGROUND

Infertility is associated with psychosocial distress and is a growing public health concern. Our objective was to report the prevalence of lifetime history of infertility among men and women Veterans.

METHODS

We used data from the U.S. Department of Veterans Affairs National Health Study for a New Generation of U.S. Veterans, a nationally representative survey of Veterans serving during Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF). The primary dependent variables were self-reported lifetime history of infertility among Veterans and their partners, defined as trying unsuccessfully to become pregnant for at least 12 months, and seeking medical help for infertility. Multiple logistic regression was used to determine whether gender was associated with lifetime history of infertility or seeking medical help for infertility, after adjusting for sociodemographic and military characteristics. All analyses were weighted to account for the complex survey design and nonresponse.

RESULTS

Among the 20,370 Veterans (16,056 men; 4,314 women) in our final analytic sample, the prevalence of lifetime history of infertility was 15.8% for women and 13.8% for men. After adjusting for age, ever married, education, race/ethnicity, component, branch of service, and deployment to OEF/OIF, compared with men, women Veterans had similar odds of lifetime history of infertility (odds ratio [OR] 1.07; 95% confidence interval [CI] 0.94, 1.20), but increased odds of seeking medical help for infertility (OR 1.35; 95% CI 1.06, 1.72).

CONCLUSIONS

Women Veterans are more likely than their male counterparts to seek care for infertility, and given their increasing numbers, the demand for infertility evaluation and care within Veterans' Affairs may increase.

The prevalence of couple infertility in the United States from a male perspective: evidence from a nationally representative sample

Infertility is a couple-based fecundity impairment, although population level research is largely based upon information reported by female partners. Of the few studies focusing on male partners, most focus on the utilization of infertility services rather than efforts to estimate the prevalence and determinants of infertility as reported by male partners. Data from a nationally representative sample of men aged 15-44 years who participated in the 2002 National Survey of Family Growth (NSFG) were used to estimate the prevalence of infertility and determinants of longer time-to-pregnancy (TTP) using the novel current duration (CD) approach. Using backward recurrence time parametric survival methods, we estimated infertility prevalence (TTP > 12 months) and time ratios (TR) associated with TTP as derived from males' reported CD of their pregnancy attempt. The estimated prevalence of infertility was 12.0% (95% CI: 7.0, 23.2). Longer TTP was associated with older male age (35-45 vs. 17-24 years) (TR: 2.49; 95% CI: 1.03, 6.03), biological childlessness (TR: 1.53; 95% CI: 1.07, 2.19) and lack of health insurance (TR: 1.73; 95% CI: 1.02, 2.94) after controlling for the differences in couples' age and other socioeconomic factors. The prevalence of infertility based on male reporting is consistent with estimates of infertility in the US found in prospective cohort studies and CD studies based on female reporting. Our findings suggest that male partners can reliably inform about couple infertility. Interventions and services aimed at reducing couple infertility should include attention to male factors associated with longer TTP identified in this study.

Exposure to a mixture of polychlorinated biphenyls and polychlorinated dibenzofurans resulted in a prolonged time to pregnancy in women

BACKGROUND

Polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs), and dibenzodioxins (PCDDs) may affect the female reproductive system in animals and humans. In 1978-1979, a mass poisoning occurred in central Taiwan due to PCB/PCDF-contaminated cooking oil; this incident was called Yucheng ("oil disease" in Chinese).

OBJECTIVE

The purpose of our study was to determine whether PCB/PCDF exposure affected fertility in exposed women.

METHODS

After the event, we followed the exposed individuals and a reference group who were sex-, age-, and community-matched. In 2003, we obtained fertility histories from Yucheng and reference women by telephone interview. We used Kaplan-Meier survival curves and multivariable Cox regression to compare time to pregnancy (TTP) between Yucheng and reference women, and we performed multiple logistic regression to determine whether PCB/PCDF exposure caused infertility.

RESULTS

In total, 412 women responded, with a median TTP of 4 months in Yucheng women and 3 months in reference women (p = 0.019). After adjusting for confounders by Cox regression, we found a fecundability ratio of 0.90 [95% confidence interval (CI), 0.80-1.00] for Yucheng women. Among the 408 women who had non-contraceptive sexual activity for > 12 months, 19.7% of Yucheng women and 9.7% of reference women did not become pregnant (i.e., they were infertile). After we adjusted for confounders by logistic regression, the infertility odds ratio was 2.34 (95% CI, 1.23-4.59) for Yucheng women compared with the reference group.

CONCLUSIONS

We found prolonged TTP and reduced fertility among women previously exposed to PCBs/PCDFs. Because of the limited sample size and the relatively small decrease in the fertility rate, these effects require cautious interpretation and further investigation for confirmation.

Can men provide accurate confounder data about their partners for Time-to-Pregnancy studies?

PURPOSE

In studies of time to pregnancy (TTP), women's health-related behaviors may confound other determinants of TTP. In many occupation-based TTP studies, all information is collected through the male partner. There are no data on the validity of the man's report of his partner's fertility-related behavior.

METHODS

We studied 202 men and their partners from the most recent pregnancy. Validity of men's reporting on their partner's use of oral contraceptives (OCs) as the last birth control method and her smoking around the beginning of TTP and agreement of coital frequency were assessed.

RESULTS

The index pregnancy was an average of 6 years before interview. Overall percentage of agreement was 81% for OCs as the last contraceptive method (kappa agreement = 0.44). Ninety-five percent of men accurately reported whether their partner smoked (kappa agreement = 0.83). Among couples agreeing on smoking status, 90% agreed on the categorical cigarette number (weighted kappa = 0.60). Reporting accuracy was not influenced by men's characteristics. Median coital frequency was eight times per month, with a weighted kappa = 0.34 after categorization.

CONCLUSIONS

Our data generally justify the use of men's reports of potential confounders in TTP studies when women's reports are not available.

Time to pregnancy and multiple births

BACKGROUND

Mothers of multiples are alleged to be more fecund than mothers of singletons. Some authors have suggested monitoring twinning rates for assessing temporal changes in a population's reproductive health.

METHODS

Using a nested case-control design, we estimated the odds of a multiple birth in relation to fecundity in the US Collaborative Perinatal Project inclusive of 8546 pregnant women who reported a known time-to-pregnancy (TTP) upon enrolment in the cohort, 1959-1966. Case mothers comprised 81 women giving birth to twins/triplets; control mothers comprised 243 women giving birth to singletons matched to case mothers on maternal age at a ratio of 3:1. The odds ratio (OR) for a multiple birth within 6 months of trying adjusting for maternal age and prior pregnancies was estimated using logistic regression. Discrete time Cox regression analysis was also utilized to estimate the fecundability OR.

RESULTS

Women with a TTP of <or=6 months were more likely to have a multiple birth than women reporting a TTP of >6 months [OR=1.95; 95% confidence interval (95% CI)=1.09-3.51]. Excluding pregnancies after 13+ months resulted in a loss of precision (OR=2.14; 95% CI=0.90-5.04).

CONCLUSIONS

These data support higher fecundity among mothers of multiples than mothers of singletons.