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Objective: To evaluate lactation duration in relation to subsequent atherosclerosis in women during midlife., Methods: The Coronary Artery Risk Development in Young Adults study is a multicenter prospective cohort that enrolled 2,787 women in 1985-1986 (ages 18-30 years, 52% black, 48% white), of whom 2,014 (72%) attended the 20-year follow-up examination in 2005-2006. We selected 846 women (46% black) without heart disease or diabetes at baseline who delivered one or more times after the baseline evaluation, had cardiometabolic risk factors measured at baseline, and had maximum common carotid intima-media thickness (mm) measured at the 20-year follow-up examination in 2005-2006. Lactation duration was summed across all postbaseline births for each woman and (n, women) categorized as: 0 to less than 1 month (n=262), 1 to less than 6 months (n=210), 6 to less than 10 months (n=169), and 10 months or greater (n=205). Multiple linear regression models estimated mean common carotid intima-media thickness (95% confidence interval) and mean differences among lactation duration groups compared with the 0 to less than 1-month group adjusted for prepregnancy obesity, cardiometabolic status, parity, and other risk factors., Results: Lactation duration had a graded inverse association with common carotid intima-media thickness; mean differences between 10 months or greater compared with 0 to less than 1 month ranged from -0.062 mm for unadjusted models (P trend <.001) to -0.029 mm for models fully adjusted for prepregnancy body mass index (BMI) and cardiometabolic risk factors, parity, smoking, and sociodemographics (P trend=.010). Stepwise addition of potential mediators (BMI, systolic blood pressure at the 20-year follow-up examination) modestly attenuated the lactation and common carotid intima-media thickness association to -0.027 and -0.023 mm (P trend=.019 and .054)., Conclusion: Shorter lactation duration is associated with subclinical atherosclerosis independent of prepregnancy cardiometabolic risk factors and traditional risk factors. The magnitude of differences in carotid artery intima-media thickness may represent greater vascular aging. Lactation may have long-term benefits that lower cardiovascular disease risk in women., Level of Evidence: II.

Objective: To examine the effect of breastfeeding during the postpartum oral glucose tolerance test (OGTT) on maternal blood glucose and insulin among women with recent gestational diabetes mellitus., Methods: Participants were enrolled in the Study of Women, Infant Feeding, and Type 2 Diabetes, a prospective observational cohort study of 1,035 Kaiser Permanente Northern California members who had been diagnosed with GDM and subsequently underwent a 2-hour 75-g OGTT at 6-9 weeks postpartum for the study enrollment examinations from 2008 to 2011. For this analysis, we selected 835 study participants who reported any intensity of lactation and were observed either breastfeeding their infants (ie, putting the infant to the breast) or not breastfeeding during the OGTT., Results: Of 835 lactating women, 205 (25%) breastfed their infants during the 2-hour 75-g OGTT at 6-9 weeks postpartum. Mean (standard deviation) duration of breastfeeding during the OGTT was 15.3 (8.1) minutes. Compared with not having breastfed during the OGTT, having breastfed during the test was associated with lower adjusted mean (95% confidence interval) 2-hour glucose (mg/dL) by -6.2 (-11.5 to -1.0; P=.02), 2-hour insulin (microunits/mL) by -15.1 (-26.8 to -3.5; P=.01), and natural log 2-hour insulin by -0.15 (-0.25 to -0.06; P<.01), and with higher insulin sensitivity index0,120 by 0.08 (0.02-0.15; P=.02), but no differences in plasma fasting glucose or insulin concentrations., Conclusion: Among postpartum women with recent gestational diabetes mellitus, breastfeeding an infant during the 2-hour 75-g OGTT may modestly lower plasma 2-hour glucose (5% lower on average) as well as insulin concentrations in response to ingestion of glucose.

Objective: To prospectively examine whether blood pressure changes persist after pregnancy among women of reproductive age., Methods: This was a prospective, population-based, observational cohort of 2,304 (1,167 black, 1,137 white) women (aged 18-30 years) who were free of hypertension at baseline (1985-1986) and reexamined up to six times at 2, 5, 7, 10, or 20 years later (2005-2006). We obtained standardized blood pressure measurements before and after pregnancies and categorized women into time-dependent groups by the cumulative number of births since baseline within each time interval (zero births [referent]; one interim birth and two or more interim births; nonhypertensive pregnancies). The study assessed differences in systolic and diastolic blood pressures among interim birth groups using multivariable, repeated measures linear regression models stratified by baseline parity (nulliparous and parous), adjusted for time, age, race, baseline covariates (blood pressure, body mass index, education, and oral contraceptive use), and follow-up covariates (smoking, antihypertensive medications, oral contraceptive use, and weight gain)., Results: Among nulliparas at baseline, mean (95% confidence interval) fully adjusted systolic and diastolic blood pressures (mm Hg), respectively, were lower by -2.06 (-2.72 to -1.41) and -1.50 (-2.08 to -0.92) after one interim birth, and lower by -1.89 (-2.63 to -1.15) and -1.29 (-1.96 to -0.63) after two or more interim births compared with no births (all P<.001). Among women already parous at baseline, adjusted mean blood pressure changes did not differ by number of subsequent births., Conclusion: A first birth is accompanied by persistent lowering of blood pressure from preconception to years after delivery. Although the biologic mechanism is unclear, pregnancy may create enduring alterations in vascular endothelial function., Level of Evidence: II.

Objective: To examine the relationship between duration of lactation and changes in maternal metabolic risk factors., Methods: This 3-year prospective study examined changes in metabolic risk factors among lactating women from preconception to postweaning and among nonlactating women from preconception to postdelivery, in comparison with nongravid women. Of 1,051 (490 black, 561 white) women who attended two consecutive study visits in years 7 (1992-1993) and 10 (1995-1996), 942 were nongravid and 109 had one interim birth. Of parous women, 48 (45%) did not lactate, and 61 (55%) lactated and weaned before year 10. The lactated and weaned women were subdivided by duration of lactation into less than 3 months and 3 months or more. Multiple linear regression models estimated mean 3-year changes in metabolic risk factors adjusted for age, race, parity, education, and behavioral covariates., Results: Both parous women who did not lactate and parous women who lactated and weaned gained more weight (+5.6, +4.4 kg) and waist girth (+5.3, +4.9 cm) than nongravid women over the 3-year interval; P<.001. Low-density lipoprotein cholesterol (+6.7 mg/dL, P<.05) and fasting insulin (+2.6 microunits, P=.06) increased more for parous women who did not lactate than for nongravid and parous women who lactated and weaned. High-density lipoprotein cholesterol decrements for both parous women who did not lactate and parous women who lactated and weaned were 4.0 mg/dL greater than for nongravid women (P<.001). Among parous, lactated and weaned women, lactation for 3 months or longer was associated with a smaller decrement in high-density lipoprotein cholesterol (-1.3 mg/dL versus -7.3 mg/dL for less than 3 months; P<.01)., Conclusion: Lactation may attenuate unfavorable metabolic risk factor changes that occur with pregnancy, with effects apparent after weaning. As a modifiable behavior, lactation may affect women's future risk of cardiovascular and metabolic diseases., Level of Evidence: II.

Objective: To examine whether pregnancy weight gains outside the Institute of Medicine (IOM) recommendations and rates of maternal weight gain are associated with neonatal complications., Methods: In a cohort of 45,245 women who delivered singletons at Kaiser Permanente Medical Care Program Northern California in 1996-1998 and who did not have gestational diabetes as of 24-28 weeks of gestation, we conducted a nested case-control study with three case groups: macrosomia (birth weight more than 4,500 g, n=391), neonatal hypoglycemia (plasma glucose less than 40 mg/dL, n=328), and hyperbilirubinemia (serum bilirubin 20 mg/dL or more, n=432) and one control group (n=652). Medical records were reviewed to ascertain the woman's prepregnancy and predelivery weight., Results: Adjusting for age, race-ethnicity, parity, plasma glucose screening value, and difference in weeks between delivery and time when last weight was measured, women who gained more than recommended by the IOM were three times more likely to have an infant with macrosomia (odds ratio [OR] 3.05, 95% confidence interval [CI] 2.19-4.26), and nearly 1.5 times as likely to have an infant with hypoglycemia (OR 1.38, 95% CI 1.01-1.89), or hyperbilirubinemia (OR 1.43, 95% CI 1.06-1.93) than women whose weight gain was in the recommended range. Women who gained less than the IOM recommendations were less likely than women in the recommended range to have an infant with macrosomia (OR 0.38, 95% CI 0.20-0.70), but equally likely to have an infant with hypoglycemia or hyperbilirubinemia. Similar results were obtained using other means of categorizing weight gain during pregnancy., Conclusion: Maternal weight gain above the IOM recommendations was associated with an increased risk of the outcomes studied., Level of Evidence: II-2.

Objective: Women with gestational diabetes mellitus (GDM) and their offspring are at increased risk of developing diabetes. Although increases in diabetes prevalence have been reported in the United States, it is unknown whether this trend is also occurring for GDM. We examined trends in the yearly cumulative incidence of GDM between the years 1991 and 2000., Methods: A cohort study of 267,051 pregnancies screened for GDM that occurred among members of the Northern California Kaiser Permanente Medical Care Program, representing 86.8% of all eligible pregnancies, was undertaken., Results: GDM was identified in 14,175 pregnancies according to the diagnostic plasma glucose thresholds of the American Diabetes Association (96.5%) or the World Health Organization (3.5%). An additional 2,743 pregnant women with GDM were identified by a hospital discharge diagnosis. The women screened in 2000 were slightly older (mean [standard deviation] age 28.8 [6.0] years) than were those screened in 1991 (28.2 [5.7] years) and more likely to be from minority ethnic groups (51.4% versus 37.3% identified as African American, Asian, Hispanic, and other). The age- and ethnicity-adjusted yearly cumulative incidence of GDM increased steadily from 5.1% in 1991 to 7.4% in 1997 and leveled off through 2000 (6.9%)., Discussion: The observed increase in yearly cumulative incidence of GDM was independent of changes in age and ethnicity of the study population. A true increase in GDM incidence might reflect or contribute to the increases in the prevalence of diabetes and obesity. Coordinated efforts are needed to alter this trend and to prevent chronic diabetes in GDM patients and their offspring., Level of Evidence: II-2

Objective: To evaluate the effect of a low-intensity behavioral therapy program on urinary incontinence in older women., Methods: A randomized clinical trial for community-dwelling women at least 55 years reporting at least one urinary incontinent episode per week was conducted. Women were randomly assigned to a behavioral therapy group (n = 77) or a control group (n = 75). The treatment group had six weekly instructional sessions on bladder training and followed individualized voiding schedules. The control group received no instruction but kept urinary diaries for 6 weeks. After this period, the control group underwent the behavioral therapy protocol. Using per-protocol analyses, t and chi(2) tests were used to compare the treatment and control groups, and paired t tests were used to evaluate the efficacy of behavioral therapy for all women (treatment and control groups before and after behavioral therapy)., Results: Women in the treatment group experienced a 50% reduction in mean number of incontinent episodes recorded on a 7-day urinary diary compared with a 15% reduction for controls (P =.001). After behavioral therapy, all women had a 40% decrease in mean weekly incontinent episodes (P =.001), which was maintained over 6 months (P <.004). Thirty (31%) women were 100% improved (dry), 40 (41%) were at least 75% improved, and 50 (52%) at least 50% improved. There were no differences in treatment efficacy by type of incontinence (stress, urge, mixed) or group assignment (treatment, control)., Conclusion: A low-intensity behavioral therapy intervention for urinary incontinence was effective and should be considered as a first-line treatment for urinary incontinence in older women.

Objective: To determine the relationship between the use of low-dose (less than 50 micrograms estrogen) oral contraceptives (OC) and myocardial infarction., Methods: In this population-based case-control study, all incident myocardial infarctions in women, ages 15-44 years who were members of the Kaiser Permanente Medical Care Program, Northern and Southern California regions were ascertained during a 39-month period from 1991 through 1994. For each woman with myocardial infarction, up to three age- and facility-matched controls were chosen at random from female members. Information about OC use (predominantly low-dose preparations) was obtained in face-to-face interviews., Results: There were 187 incident cases of myocardial infarction during 3.6 million woman-years of observation (incidence rate, 5.2 per 100,000 woman-years). The prevalence of several risk factors for myocardial infarction was lower in controls who were current users of OCs than in controls who were noncurrent (past and never) users. The odds ratio for myocardial infarction in current OC users compared with noncurrent users was 1.65 (95% confidence interval 0.45, 6.06) after adjustment for major risk factors and for race and ethnicity, corresponding to an excess risk of less than one case per 100,000 woman-years. The study had 80% power to detect a relative risk of 2.3 (one-sided test, alpha = .05). The odds ratio of myocardial infarction in past OC users was not elevated., Conclusion: With respect to myocardial infarction, low-dose oral contraceptives can be used safely by women who lack risk factors for coronary heart disease.

Objective: To compare all-cause and specific-cause mortality rates in women who had or had not used long-term postmenopausal estrogen replacement therapy (ERT)., Methods: We identified women who used long-term postmenopausal ERT and compared them with a sample of age-matched postmenopausal nonusers. Through linking of these subjects' medical record numbers to various data bases, we examined survivorship and cause of death among estrogen users and nonusers. The risk of death in 232 postmenopausal women who began ERT within 3 years of menopause and used it for at least 5 years was compared with that of 222 age-matched postmenopausal nonusers. In the users, the mean length of estrogen use was 17.1 years., Results: Statistically significant reductions in all-cause mortality were found in users compared with nonusers. For death from any cause, the age-adjusted relative risk (RR) and associated 95% confidence interval (CI) in estrogen users was 0.54 (0.38-0.76). The reduction in all-cause mortality was largely due to reductions in coronary heart disease (RR 0.40, CI 0.16-1.02) and other cardiovascular disease (RR 0.27, CI 0.10-0.71). Overall cancer mortality was similar in the two groups (RR 0.85, CI 0.46-1.58), although estrogen users had a higher risk of death from breast cancer (RR 1.89, CI 0.43-8.36) and lower risk of death from lung cancer (RR 0.22, CI 0.04-1.15)., Conclusion: Long-term ERT use is associated with lower all-cause mortality and confers this apparent protection primarily through reduction in cardiovascular disease.