Examples of a combined approach using in vivo as well as in vitro methods for the assessment of prenatal toxicity are presented. The topics discussed include the analysis of the possible embryotoxic potential of valproic acid (VPA), female sex hormones, bis(tri-n-butyltin) oxide (TBTO), and acyclovir and the problem of supplementing in vitro systems with drug-metabolizing activity.
prenatal toxicity assessment, embryotoxic potential valproic acid, in vitro embryotoxicity testing, teratogenicity sex hormones, prenatal toxicology methods, developmental toxicity screening, reproductive toxicology in vivo in vitro, embryo culture toxicity assay, acyclovir prenatal safety, environmental toxicant reproductive effects
PMID 3104025 3104025 DOI 10.1289/ehp.867089 10.1289/ehp.867089
Cite this article
Neubert, D., Blankenburg, G., Chahoud, I., Franz, G., Herken, R., Kastner, M., Klug, S., Kröger, J., Krowke, R., & Lewandowski, C. (1986). Results of in vivo and in vitro studies for assessing prenatal toxicity. Environmental health perspectives, 70, 89-103. https://doi.org/10.1289/ehp.867089
Neubert D, Blankenburg G, Chahoud I, Franz G, Herken R, Kastner M, et al. Results of in vivo and in vitro studies for assessing prenatal toxicity. Environ Health Perspect. 1986;70:89-103. doi:10.1289/ehp.867089
Neubert, Diether, et al. "Results of in vivo and in vitro studies for assessing prenatal toxicity." Environmental health perspectives, vol. 70, 1986, pp. 89-103.
The determinants of successful human reproduction and development may act as early as periconceptionally, underscoring the need to capture exposures during these critical windows when assessing potential toxicants. To identify such toxicants, couples must be studied longitudinally prior to conception without regard to a couple's ability to ascertain a clinically recognized pregnancy. We examined the utility and feasibility of prospective pregnancy study designs by conducting a systematic review of the literature to summarize relevant information regarding the planning, implementation, and success of previously published prospective pregnancy studies. Information concerning design elements and participation was abstracted from 15 eligible studies (from a total of 20 identified studies) using a standardized form. The primary author of each study was contacted to review our summary of their work and obtain missing information. Our findings confirm the ability to recruit women/couples from diverse populations using a variety of recruitment strategies. Among the studies we reviewed, 4-97% of eligible individuals were successfully contacted, with enrollment rates ranging from 42 to 100%. Length of follow-up varied from 3 to 12 months. A high percentage of women provided urine (57-98%) and blood (86-91%) specimens and most male partners (94-100%) provided semen samples. These data support the feasibility of this design.
Harville EW et al., 2019·Paediatr Perinat Epidemiol
Preconception health may have intergenerational influences. We have formed the PrePARED (Preconception Period Analysis of Risks and Exposures influencing health and Development) research consortium to address methodological, conceptual, and generalisability gaps in the literature. The consortium will investigate the effects (1) fertility and miscarriage; (2) pregnancy-related conditions; (3) perinatal and child health; and (4) adult health outcomes. A study is eligible if it has data measured for at least one preconception time point, has a minimum of selected core data, and is open to collaboration and data harmonisation. The included studies are a mix of studies following women or couples intending to conceive, general-health cohorts that cover the reproductive years, and pregnancy/child cohort studies that have been linked with preconception data. The majority of the participating studies are prospective cohorts, but a few are clinical trials or record linkages. Data analysis will begin with harmonisation of data collected across cohorts. Initial areas of interest include nutrition and obesity; tobacco, marijuana, and other substance use; and cardiovascular risk factors. Twenty-three cohorts with data on almost 200 000 women have combined to form this consortium, begun in 2018. Twelve studies are of women or couples actively planning pregnancy, and six are general-population cohorts that cover the reproductive years; the remainder have some other design. The primary focus for four was cardiovascular health, eight was fertility, one was environmental exposures, three was child health, and the remainder general women's health. Among other cohorts assessed for inclusion, the most common reason for ineligibility was lack of prospectively collected preconception data. The consortium will serve as a resource for research in many subject areas related to preconception health, with implications for science, practice, and policy.
Schisterman EF et al., 2013·Paediatr Perinat Epidemiol
Low-dose aspirin (LDA) has been proposed to improve pregnancy outcomes in couples experiencing recurrent pregnancy loss. However, results from studies of LDA on pregnancy outcomes have been inconsistent, perhaps because most studies evaluated LDA-initiated post-conception. The purpose of the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial was to determine whether preconception-initiated LDA improves livebirth rates in women with one to two prior losses. We performed a multicentre, block randomised, double-blind, placebo-controlled trial. Study participants were recruited using community-based advertisements and physician referral to four university medical centres in the US (2006-12). Eligible women were aged 18-40 years actively trying to conceive, with one to two prior losses. Participants were randomised to receive daily LDA (81 mg/day) or a matching placebo, and all were provided with daily 400-mcg folic acid. Follow-up continued for ≤6 menstrual cycles while attempting to conceive. For those who conceived, treatment was continued until 36 weeks gestation. The primary outcome was the cumulative livebirth rate over the trial period. There were 1228 women randomised (615 LDA, 613 placebo). Participants had a mean age of 28.7, were mostly white (95%), well educated (86% more than high school education), and employed (75%) with a household income >$100 000 annually (40%). The characteristics of those in the treatment and placebo arms were well balanced. We describe the study design, recruitment, data collection, and baseline characteristics of participants enrolled in EAGeR, which aimed to determine the effect of LDA on livebirth and other pregnancy outcomes in these women.
Fertility AwarenessResearch Methodology
Open Access
Although there has been growing concern about the effects of environmental exposures on human fertility, standard epidemiologic study designs may not collect sufficient data to identify subtle effects while properly adjusting for confounding. In particular, results from conventional time to pregnancy studies can be driven by the many sources of bias inherent in these studies. By prospectively collecting detailed records of menstrual bleeding, occurrences of intercourse, and a marker of ovulation day in each menstrual cycle, precise information on exposure effects can be obtained, adjusting for many of the primary sources of bias. This article provides an overview of the different types of study designs, focusing on the data required, the practical advantages and disadvantages of each design, and the statistical methods required to take full advantage of the available data. We conclude that detailed prospective studies allowing inferences on day-specific probabilities of conception should be considered as the gold standard for studying the effects of environmental exposures on fertility.