Penelope P. Howards

Learn More
BACKGROUND Coffee and caffeine have been inconsistently found to be associated with increased risk of clinical miscarriage-a potentially important association given the high prevalence of exposure. METHODS Women were recruited before or early in pregnancy and interviewed regarding sources of caffeine, including assessment of changes over the perinatal(More)
Planning study visits during specific menstrual cycle phases is important if the exposure or outcome is influenced by hormonal variation. However, hormone profiles differ across cycles and across women. The value of using fertility monitors to time clinic visits was evaluated in the BioCycle Study (2005-2007). Women aged 18-44 years (mean, 27.4) with(More)
Epidemiologic studies suggest that prenatal stress is associated with preterm birth, low birth weight, and peripartum anxiety and depressive symptoms. The most recent population-based study, assessing trends in stress experienced in the year before an infant's birth, used 1990-1995 data from 11 states participating in the Pregnancy Risk Assessment(More)
SETTING National tuberculosis (TB) treatment facility in the country of Georgia. OBJECTIVE To determine the prevalence of diabetes mellitus (DM) and pre-DM among patients with TB using glycosylated-hemoglobin (HbA1c), and to estimate the association between DM and clinical characteristics and response to anti-tuberculosis treatment. DESIGN A cohort(More)
OBJECTIVE A physiologic predisposition toward hypertension is theorized to result from the combination of intrauterine growth restriction followed by rapid catch-up growth. The objective of this study was to evaluate the effects of birth weight and weight gain during childhood on the risk for high blood pressure in childhood and to identify discrete periods(More)
Despite the high incidence of spontaneous abortion, little is known about its causes, in part because of the challenge of assembling a large cohort of women in early pregnancy for prospective study. We describe the effectiveness of recruitment strategies used in Right From The Start (RFTS), a prospective, community-based study of spontaneous abortion.(More)
BACKGROUND Cadmium, lead and mercury have been identified in human follicular fluid and ovarian tissue, and have been associated with adverse reproductive outcomes in epidemiologic studies; however, few studies have examined the relationship between blood metal levels and reproductive hormones. METHODS Among 252 premenopausal women aged 18-44 years, we(More)
Most studies of spontaneous abortion are subject to left truncation, because conception is not observed and thus pregnant women are enrolled postconception. Cox regression can account for left truncation but uses gestational age data, which may be inaccurate. Dating is affected by reporting errors and variability in the day of ovulation. These errors may be(More)
BACKGROUND Serum concentrations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were assessed in relation to miscarriage in a population of mid-Ohio River Valley residents highly exposed to PFOA through contaminated drinking water. METHODS Serum PFOA and PFOS concentrations were measured in 1129 women in 2005-2006 who reported(More)
OBJECTIVE To determine whether use of antiepileptic drugs during pregnancy may increase the risk of spontaneous abortion or stillbirth. DESIGN Population based cohort study. SETTING Register based study in Denmark, 1997-2008. PARTICIPANTS 983,305 pregnancies identified in the Danish medical birth register and the Danish national hospital discharge(More)