Maternal Smoking During Pregnancy and Offspring Birth Weight: A Genetically-Informed Approach Comparing Multiple Raters

Abstract

Maternal smoking during pregnancy (SDP) is a significant public health concern with adverse consequences to the health and well-being of the fetus. There is considerable debate about the best method of assessing SDP, including birth/medical records, timeline follow-back approaches, multiple reporters, and biological verification (e.g., cotinine). This is particularly salient for genetically-informed approaches where it is not always possible or practical to do a prospective study starting during the prenatal period when concurrent biological specimen samples can be collected with ease. In a sample of families (N = 173) specifically selected for sibling pairs discordant for prenatal smoking exposure, we: (1) compare rates of agreement across different types of report—maternal report of SDP, paternal report of maternal SDP, and SDP contained on birth records from the Department of Vital Statistics; (2) examine whether SDP is predictive of birth weight outcomes using our best SDP report as identified via step (1); and (3) use a sibling-comparison approach that controls for genetic and familial influences that siblings share in order to assess the effects of SDP on birth weight. Results show high agreement between reporters and support the utility of retrospective report of SDP. Further, we replicate a causal association between SDP and birth weight, wherein SDP results in reduced birth weight even when accounting for genetic and familial confounding factors via a sibling comparison approach.

Effects of Maternal Smoking during Pregnancy on Offspring Externalizing Problems: Contextual Effects in a Sample of Female Twins

“…The current study is also not without some degree of inaccuracy in the MSDP variables, as they are all based on retrospective report. Though it should be noted that in other Missouri twin studies (Heath, Knopik et al 2003; Reich, Todd et al 2003) and Missouri family studies (Knopik et al, current issue) we have observed high reliability and stability of maternal reporting, suggesting that they are likely to be suitable for studying adverse “parent behavior”-“child outcome” associations. Overall, the current study findings may not generalize to other studies utilizing alternative measures of MSDP.…”

“…Third, our analyses utilized a broad measure of a retrospectively reported maternal smoking during pregnancy. While previous studies support the reliability and utility of retrospective reporting of pregnancy variables by mothers (Heath, Knopik et al 2003; Reich, Todd et al 2003; Christensen, Tobiassen et al 2004; Pickett, Kasza et al 2009; Knopik, Marceau et al ( current issue )), readers should be aware that the sensitivity of the MSDP variable (i.e., its ability to reflect the amount of tobacco exposure by the offspring in utero ) has been shown to be an important factor in the observation of MSDP effects. In an earlier report by Boutwell et al (2011), broadly defined MSDP was not associated with offspring externalizing behavioral problems, however, a continuous measure of MSDP (i.e., the number of cigarette packs smoked per day) was associated with childhood externalizing, such that more packs smoked per day resulted in higher scores on the externalizing problem scale (among matched subjects).…”

The Importance of the Prenatal Environment in Behavioral Genetics: Introduction to Special Issue

“…The papers by Knopik et al (2016) and Neiderhiser et al (2016) both address the value of self-report data for assessment of the prenatal environment. In both projects self-report data were collected retrospectively, but other strategies were also used to enhance both the accuracy of the self-report data and the detail of the information collected.…”

“…This study also reported that the combined effects of genetic, perinatal, and postnatal risks interact to influence internalizing and externalizing symptoms during early childhood. Knopik et al (2016) focused on identifying the optimal method for assessing smoking during pregnancy (SDP) by comparing rates of agreement across maternal reports, paternal reports of maternal smoking behavior and birth records. These findings support the use of self-report data from mothers and fathers and found a causal association between SDP and birth weight, after controlling for genetic and familial confounds using a sibling comparison approach.…”

Missouri Mothers and Their Children: A Family Study of the Effects of Genetics and the Prenatal Environment

“…The first paper using MO-MATCH data (Knopik et al, under review) examined rates of agreement across birth record report of SDP, retrospective maternal report of SDP, and retrospective paternal report of SDP. Specifically, we compared reports for any SDP during pregnancy and for quantity of cigarettes smoked across each pregnancy.…”