Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2019 Jul 1.
Published in final edited form as: Neurotoxicol Teratol. 2018 Jun 5;68:84–90. doi: 10.1016/j.ntt.2018.06.001

Prevalence and Associated Birth Outcomes of Co-Use of Cannabis and Tobacco Cigarettes during Pregnancy

Victoria H Coleman-Cowger 1, Emmanuel Oga 2, Erica N Peters 3, Katrina Mark 4
PMCID: PMC6054553  NIHMSID: NIHMS976069  PMID: 29883744

Abstract

Use of cannabis and use of tobacco overlap, and co-use of cannabis and tobacco has increased over the past decade among adults. The current study aims to document the prevalence and correlates of co-use of cannabis and tobacco cigarettes among adult pregnant women utilizing secondary data from a larger study that compared and validated screeners for illicit and prescription drug use during pregnancy. Pregnant women (N=500; 71% African American; 65% never married, average age of 28 years) were recruited from two urban University obstetric clinics between January and December 2017. Participants self-reported demographic, cannabis, and tobacco cigarette use characteristics, and provided urine and hair samples for drug testing. Within two weeks after due date, research staff reviewed participants’ electronic medical records to collect birth outcome data. Results showed that 9.0% reported co-use of cannabis and tobacco, 12.1% reported cannabis only use, 7.8% reported tobacco cigarette only use, and 71.1% reported no cannabis or tobacco cigarette use in the past month. The birth outcomes to emerge as significant correlates of co-use of cannabis and tobacco cigarettes were small head circumference, and the occurrence of birth defects, with the co-use group having the highest odds of a small head circumference [aOR: 5.7 (1.1–28.9)] and birth defects [aOR: 3.1 (1.2–8.3)] compared with other use groups. The cannabis only group had 12 times higher odds of a stillbirth or miscarriage (aOR=12.1). Screening and interventions to address concurrent cannabis and tobacco use during pregnancy are needed, particularly among subpopulations with higher co-use rates. It is imperative to further explore and highlight the possible health implications of maternal co-use given the high prevalence rates found in this study sample.

Keywords: co-use, prenatal cannabis exposure, tobacco, birth outcomes, pregnancy

1. Introduction

Cannabis is the most commonly used illicit drug globally and in the United States (World Health Organization (WHO), 2016), and rates of cannabis use among US adults have risen significantly in the past 15 years (Hasin et al., 2015). In contrast, tobacco use has declined (WHO, 2015), although it remains one of the world’s biggest public health threats, contributing to the deaths of approximately 7 million people each year (WHO, 2017). In the US general population, co-use of cannabis and tobacco has increased significantly over the past decade (Schauer et al., 2015). Co-use of cannabis and tobacco can refer to many different behavioral patterns, including use in the same episode, use within the same product (i.e., blunt or spliff smoking), or use within the same time-period (in the past month). Co-use of cannabis and tobacco, relative to use of either cannabis or tobacco alone, is associated with several concerning clinical correlates, including increased risk of cannabis use disorder (CUD), exacerbation of mental health symptoms, and poorer cessation outcomes (Agrawal et al., 2012; Agrawal and Lynskey, 2009; Coleman-Cowger et al., 2017; Montgomery, 2015; Peters et al., 2012; Ramo et al., 2012). Preliminary evidence also suggests that co-use of cannabis and tobacco may be associated with additive, or even multiplicative, adverse health consequences relative to tobacco use only (Coleman-Cowger et al., 2017; Peters et al., 2016).

With rates of co-use of marijuana and tobacco increasing significantly in the US, a critical question is how prevalent co-use is among vulnerable populations who may be especially susceptible to associated negative health implications, such as pregnant women. Among pregnant women in the 2005– 2014 data from the US National Survey on Drug Use and Health, co-use of cannabis and tobacco was significantly more prevalent than cannabis only use (3.3% vs. 1.0%) but less common than tobacco only use (13.3%) (Coleman-Cowger et al., 2017). Co-use of cannabis and tobacco was associated with being younger and Black or Hispanic, and having past month use of alcohol and other illicit drugs (Coleman- Cowger et al., 2017). In other studies, substance use during pregnancy is more common in women who are younger, less educated, single, unemployed (Havens et al., 2009), socioeconomically disadvantaged have a partner who smokes (Giglia et al., 2007), or belong to a racial or ethnic minority group (El Marroun et al., 2008; Ko et al., 2015), as well as in multigravid women (i.e., women who have been pregnant more than once) and women with unplanned pregnancies (El Marroun et al., 2008). Although co-use of cannabis and tobacco during pregnancy appears to be higher among certain subpopulations characterized by demographic characteristics and by behaviors associated with adverse health effects, research on co-use of cannabis and tobacco among high risk populations of pregnant women is limited.

The negative health consequences of smoking tobacco during pregnancy are well-known (US Department of Health and Human Services (USDHHS), 2014) but the evidence base for the health consequences of smoking cannabis during pregnancy is less robust (Gunn et al., 2016). Extant findings suggest links to reduced birth weight (though with smaller effects than those seen with tobacco use), increased risk of babies small for gestational age, increased risk of neonatal intensive care admission, poorer cognitive performance in adolescence, and maternal anemia (Gunn et al., 2016); however, the limitations of extant research are significant and include the small number of studies, small samples, underreporting of use, and inability to control for confounding effects of other substance use (Volkow et al., 2014). Two notable longitudinal studies of prenatal marijuana exposure (Fried and Makin, 1987; Richardson et al., 2002) found no association between cannabis use during pregnancy and increased miscarriage rates, premature deliveries or any other complications, but did find differences in neonatal behaviors (i.e., increased tremors and startles and poorer habituation to visual stimuli) and neuropsychological outcomes at 10 years of age (i.e., effects on learning, memory, and impulsivity).Most studies on the effects of cannabis use on birth outcomes did statistically control for tobacco smoking, showing the independent effects of cannabis use on outcomes. To our knowledge, no studies have examined the unique research question of how tobacco and cannabis interact synergistically to influence birth outcomes; i.e., does co-use of cannabis and tobacco, relative to use of either one alone, compound adverse health consequences to the mother and developing fetus?

Existing studies on the health consequences of smoking cannabis during pregnancy were initiated over 30 years ago. In the past two decades, 29 US states have implemented medicinal cannabis laws and 8 states plus the District of Columbia have legalized adult recreational use of cannabis. The impact of changing state and local policies legalizing cannabis remains unclear, but there is some evidence that these policies contribute to greater cannabis availability and the increasing perception that cannabis use is harmless (Budney and Borodovsky, 2017; Schulenberg et al., 2017), both of which could lead to changing cannabis use patterns among pregnant women. Because cannabis and tobacco are so closely associated, changing cannabis use patterns could have downstream effects on tobacco use patterns. Furthermore, exponential increases in tetrahydrocannabinol (THC) potency, the primary psychoactive constituent of cannabis, over the past decade, combined with the fact that maternal tissues act as a reservoir for THC and other cannabinoids which results in prolonged fetal exposure, could make cannabis difficult to quit during pregnancy (Budney and Borodovsky, 2017; Schulenberg et al., 2017). For all of these reasons, current research on the prevalence and associated birth outcomes of co-use of cannabis and tobacco use is needed.

The purpose of this study is to: 1) describe the prevalence of co-use of cannabis and tobacco cigarettes reported by a convenience sample of pregnant women presenting to two urban prenatal clinics; 2) outline correlates of co-use of cannabis and tobacco cigarettes; and 3) compare birth outcomes between pregnant women who co-use cannabis and tobacco cigarettes, who currently smoke tobacco cigarettes but do not use cannabis, who currently use cannabis but do not smoke tobacco cigarettes, and who do not currently use cannabis or tobacco cigarettes.

2. Materials and Methods

2.1. Sample

This study’s sample was recruited from two obstetric clinics in Maryland as part of a larger study to compare and validate screeners for illicit and prescription drug use during pregnancy. Pregnant women were enrolled in the study if they met the following criteria: 1) currently pregnant; 2) age 18 years or older; 3) able to speak and understand English sufficiently to provide informed consent; and 4) natural hair length at least 3 cm to allow for drug testing. Participants were compensated with a $50 gift card on completion of enrollment surveys and providing hair and urine samples. Data were collected between January and December 2017. Participants provided informed consent and signed a HIPAA release form to allow access to their and their baby’s electronic medical records. All forms used in the study were approved by the Institutional Review Boards (IRB) of Battelle Memorial Institute and the University of Maryland-Baltimore. Details of study methodology have been published elsewhere (Coleman-Cowger et al., 2018).

2.2. Procedures

Women attending prenatal appointments at the two clinics were approached by study staff for interest in study participation, then evaluated for eligibility. Study staff administered informed consent to women who expressed interest and met the eligibility criteria. The informed consent detailed the nature of the study, potential benefits and risks, procedures and compensation. Once consented, participants signed a HIPAA release then completed a demographic questionnaire and the 4P’s Plus questionnaire (Chasnoff et al., 2007), along with two additional questionnaires and an in-depth interview (not reported herein). Participants also provided urine and hair samples for drug testing, to allow for detection of short-term (urine) and longer-term (hair) substance use. Urine was tested onsite with iCup® Dx 14 Panel Drug Test Cup, and hair was shipped to Quest Diagnostics for testing. Within two weeks after due date, study staff conducted a review of the Electronic Medical Records (EMR) of participants to collect information on birth outcomes, including birthweight, birth length, head circumference, Apgar scores, gestational age (prematurity vs. term), occurrence of birth defects, stillbirths or miscarriages (vs. live births) and neonatal intensive care unit (NICU) admissions. These outcomes were selected based on previous associations with substance use found in the literature. A total of 1170 pregnant women were approached for this study in both sites, 719 met eligibility criteria, and 500 were enrolled.

2.3. Measures

Data was collected from 3 sources for this study: interviewer-administered demographic and 4P’s Plus questionnaire, EMR chart review, and drug screen results. Additional measures collected but not reported in this paper were the Substance Use Risk Profile-Pregnancy (SURP-P)(Yonkers et al., 2010) and the NIDA Quick Screen and ASSIST (NIoD, 2011; Smith et al., 2010), along with an in-depth interview assessing patient perception of the presented screeners.

2.3.1. Demographics Questionnaire

The demographics questionnaire collected information on age, marital status, education, race/ethnicity, and employment status. An obstetric history was also collected that detailed number of previous pregnancies, miscarriages, live births, birth defects, due date for current pregnancy, date of last menstrual period, and pregnancy intention.

2.3.2. 4P’s Plus Questionnaire

The 4P’s Plus is a validated questionnaire for substance use screening developed by Chasnoff and colleagues (Chasnoff et al., 2007). The 4 P’s inquires about use by Parents, Partner, as well as use in the Past and during Pregnancy. This survey contains 5 items and includes questions on smoking, alcohol use and illicit drug use. This questionnaire elicited smoking history by asking “in the month before you knew you were pregnant, how many cigarettes did you smoke?” and cannabis use history by asking “in the month before you knew you were pregnant, how much marijuana did you smoke?” Follow-up questions inquired about last month use; for cigarettes: “and last month, about how many days a week did you smoke a cigarette?” and for cannabis: “and last month, about how many days a week did you use marijuana?” The questionnaire did not obtain information about use of non-cigarette tobacco products.

2.3.3. EMR Chart Review

We obtained medical histories from the EMR of participants. We collected previously documented histories of substance use (tobacco smoking and cannabis use) to confirm responses from the survey. We also collected birth outcomes data for all deliveries (to date) from participants in the study. The EMR was reviewed for date of birth, sex of baby, outcome of delivery, gestational age at delivery, birth weight, birth length, head circumference, Apgar scores, whether baby was admitted to the NICU, and presence or absence of birth defects (e.g., cardiac; musculoskeletal; gastrointestinal). We defined low birth weight, length and head circumference in accordance with Centers for Disease Control and Prevention (CDC) recommendations to use the WHO guidelines for children from birth to 2 years old (CDC, 2000). As such we used mean values for girls and boys minus 2 standard deviations (WHO, 2007). The cutoffs of girls and boys were: low birth weight <2400 g and <2500 g; low birth length <45.4 cm and <46.1 cm; and low birth head circumference <31.5 cm and <31.9 cm respectively (WHO, 2007). Prematurity was defined as gestational age of less than 37 weeks.

2.3.4. Urine and Hair Sample Drug Testing

To measure participants’ substance use and verify marijuana use, hair and urine samples were collected and tested for illicit substances including THC. Utilizing both urine and hair sample drug testing allowed for examination of drug use history up to the past 90 days and serves as a validation of survey responses.

2.4. Analysis

We utilized survey responses (validated with EMR data and drug testing) to classify participants into co use (tobacco cigarette smoking and cannabis use), tobacco cigarette smoking only, cannabis use only, or no-use (neither tobacco cigarette smoking nor cannabis use) categories. Based on urine drug screening, the sensitivity of the 4Ps Plus for cannabis use was 78% and specificity was 95%. We did not biochemically verify tobacco use. For 8 participants with missing baseline data, survey responses from the 1-week follow up were used, in addition to demographic information gleaned from the enrollment spreadsheets.

First, characteristics of participants, sociodemographic features and obstetric history were provided for the 4 groups - co-use, tobacco cigarettes only, cannabis only, and no-use groups. For continuous variables, we assessed variables for normality, outliers and implausible values using scatter plots, histograms, quantile plots and Shapiro-Wilk normality test. We then compared means for the 4 groups using analysis of variance (ANOVA). For categorical variables, we compared proportions using Chi- Square tests. Second, we described prevalence of tobacco cigarette smoking, cannabis only use, tobacco cigarette and marijuana co-use, and no-use in the study sample. Third, multivariable logistic regression was used to compare differences in use groups by demographic factors. Furthermore, using multivariable logistic regression, we examined the strength of the relationship between birth outcomes and prenatal use groups (i.e., co-use of cannabis and tobacco cigarettes, use of tobacco cigarettes only, use of cannabis only, and no cannabis or tobacco cigarette use). For covariates selection for regression models, we utilized stepwise regression to identify the best combination of independent variables to add to the model. Forward selection method was used in which covariates were added to the model one at a time and all covariates with p-value <0.1 were added to the final model. In accordance with the recommendation by Cepeda and colleagues (2003), for birth outcomes with fewer than 8 outcomes per covariate, propensity score weighted regression was used to identify factors associated with such outcomes rather ordinary logistic regression. In general, p-values less than 0.05 were considered statistically significant. All statistical analyses were conducted with SPSS version 25 and STATA version 13.

3. Results

3.1. Demographic Characteristics

Table 1 outlines the demographic characteristics of the study participants. There were 500 participants enrolled into the study from two urban obstetrics clinics. Overall, the sample consisted primarily of African-American women (71.3%) who had never been married (65.3%), with an average age of 27.9 (SD=5.2) years. Approximately 32% of the study sample reported having had a previous miscarriage or stillbirth. With regard to pregnancy intention, slightly over one-third of study participants (34%) wanted to be pregnant at the time they became pregnant. Characteristics were examined by the four use groups (co-use, cannabis-only, tobacco cigarette-only, and no use), and significant differences were noted by race, employment, education level, marital status, trimester, pregnancy intention, past-month alcohol and drug use, and study site. The co-use and cannabis only groups were more likely than the no use group to be African-American, unemployed, and to present to the clinic serving lower SES women. The co-use group was most likely to have never married, report past-month alcohol and drug use, and have no intention of becoming pregnant when they did or in the future. The tobacco cigarette only group was more likely to have less than a high school education, and be in the third trimester of pregnancy.

Table 1:

Characteristics of Study Participants

Total
(N=500)		 Co-Use
(n=45)		 Tobacco
Cigarettes
Only (n=39)		 Cannabis
Only (n=60)		 No-Use
(n=354)		 p-value
Age, mean (SD) 27.9 (5.2) 26.7 (4.8) 27.9 (4.4) 27.3 (4.9) 28.2 (5.4) 0.19
Race/Ethnicity, n (%) <0.001*
Non-Hispanic White 104 (20.9) 3 (6.7) 9 (23.1) 3 (5.0) 89 (25.1)
Black/African American 354 (71.1) 42 (93.3) 30 (76.9) 56 (93.3) 226 (63.8)
Other 40 (8.0) 0 (0.00) 0 (0.00) 1 (1.7) 39 (11.0)
Employed, n (%) 322 (66.0) 19 (42.2) 19 (51.4) 30 (51.7) 254 (73.0) <0.001*
Ever married, n (%) 171 (34.7) 5 (11.1) 7 (18.0) 10 (16.7) 149 (42.7) <0.001*
Education, n (%) <0.001*
College graduate 144 (29.3) 3 (6.8) 1 (2.6) 4 (6.7) 136 (39.0)
High school/some college 307 (62.4) 35 (79.6) 30 (76.9) 52 (86.7) 190 (54.4)
Less than high school 41 (8.3) 6 (13.6) 8 (20.5) 4 (6.7) 23 (6.6)
Trimester, n (%) 0.001*
1st 150 (30.1) 23 (51.1) 9 (23.1) 25 (41.7) 93 (26.3)
2nd 172 (34.5) 14 (31.1) 15 (38.5) 23 (38.3) 120 (33.9)
3rd 176 (35.3) 8 (17.8) 15 (38.5) 12 (20.0) 141 (39.8)
History of miscarriage/stillbirth, n (%) 158 (31.7) 19 (42.2) 11 (28.2) 25 (41.7) 103 (29.1) 0.10
History of birth defects, n (%) 23 (4.6) 2 (4.4) 1 (2.6) 3 (5.0) 17 (4.8) 0.94
Pregnancy Intention, n (%) 0.02*
Wanted to be pregnant sooner 83 (16.8) 9 (20.0) 3 (7.7) 5 (8.3) 66 (18.9)
Wanted to be pregnant later 185 (37.5) 19 (42.2) 20 (51.3) 28 (46.7) 118 (33.8)
Wanted to be pregnant then 166 (33.7) 8 (17.8) 10 (25.6) 18 (30.0) 130 (37.3)
Didn’t want to be pregnant then or any time in the future 59 (12.0) 9 (20.0) 6 (15.4) 9 (15.0) 35 (10.0)
Study Site, n (%) <0.001*
Clinic 1 (Medicaid-eligible patients) 327 (65.7) 42 (93.3) 35 (89.7) 56 (93.3) 194 (54.8)
Clinic 2 (Privately insured patients) 171 (34.3) 3 (6.7) 4 (10.3) 4 (6.7) 160 (45.2)
Past-month Alcohol Use, n (%) 96 (19.3) 13 (28.9) 5 (12.8) 17 (28.3) 61 (17.2) 0.05*
Days of Past-month Tobacco Cigarette Smoking, n (%) <0.001*
Did not smoke 414 (83.1) -- -- 60 (100.0) 354 (100.0)
Less than 1 day a week 7 (1.4) 2 (4.4) 5 (12.8) -- --
1–2 days a week 15 (3.0) 9 (20.0) 6 (15.4) -- --
3–6 days a week 14 (2.8) 7 (15.6) 7 (18.0) -- --
Everyday 48 (9.6) 27 (60.0) 21 (53.9) -- --
Days of Past-month Marijuana Use, n (%) <0.001*
Did not use marijuana 393 (78.9) -- 39 (100.0) -- 354 (100.0)
Less than 1 day a week 17 (3.4) 8 (17.8) -- 9 (15.0) --
1–2 days a week 23 (4.6) 5 (11.1) -- 18 (30.0) --
3–6 days a week 24 (4.8) 13 (28.9) -- 11 (18.3) --
Everyday 41 (8.2) 19 (42.2) -- 22 (36.7) --
Positive Urine Drug Screen, n (%)
Opiatesa 19 (3.8) 5 (11.1) 5 (12.8) 2 (3.3) 7 (2.0) <0.001*
Cocaine 4 (0.8) 2 (4.4) -- -- 2 (0.56) 0.04*
Amphetamine/Methamphetamine 6 (1.2) 1 (2.2) 1 (2.6) -- 4(1.13) 0.63
Benzodiazepines 5 (1.0) 1 (2.2) -- 3 (5.0) 1 (0.28) 0.01*
Open in a new tab
*

Denotes statistically significant (α=0.05) difference between use groups.

a

includes heroin, methadone, oxycodone and buprenorphine

3.2. Prevalence and Predictors of Co-use

Of the 500 participants, 9.0% reported past-month co-use of cannabis and tobacco cigarettes, 12.1% reported cannabis only use, 7.8% reported tobacco cigarette only use, and 71.1% reported no cannabis or tobacco cigarette use in the past month. Relative to a population-based sample of US pregnant women ages 12–44 between 2005 and 2014 (Coleman-Cowger et al., 2017), rates of co-use of cannabis and tobacco (9.0% vs. 3.3%) and of cannabis only use (12.1% vs. 1.0%) appeared higher, and rates of tobacco only use appeared lower (7.8% vs. 13.3%); however, the rates in the population-based sample of US pregnant women relate to use of cigarettes plus use of other tobacco products, whereas the rates in the current sample relate to use of cigarettes only. Self-report of use varied by trimester, with co-use reported most often in the first trimester (51.1% of group; p = 0.001). Among 84 participants who reported that they smoked tobacco cigarettes in the past month, 57% smoked every day, 17% smoked 3–6 days a week, 18% smoked 1–2 days a week and 8% smoked less than 1 day a week. Among 105 participants who reported that they used cannabis in the past month, 39% used cannabis every day, 23% used cannabis 3–6 days a week, 22% used cannabis 1–2 days a week and 16% used cannabis less than 1 day a week. The single predictor of co-use of cannabis and tobacco cigarettes (n=45) was pregnancy intention [aOR: 0.2 (0.1–0.6)], utilizing the no use group as the referent (table not shown, adjusted for age, race, marital status, trimester, alcohol use, employment and education).

3.3. Birth Outcomes

Birth outcome data is reported on a subset of the 500 participants who had delivered by March 2018 (n=360). Except for delivery outcome - (stillbirth/miscarriage vs. live birth), all birth outcomes are reported for live, singleton pregnancies only (n=338). Of these, 23 reported smoking only tobacco cigarettes, 36 reported using cannabis alone, 22 reported using both cannabis and tobacco cigarettes, and 257 reported not using either (the no-use group). No significant differences were found between use groups for birthweight, birth length, APGAR scores, NICU admissions, or gestational age at birth (see Table 2). Significant differences were found with regard to: 1) head circumference, when compared with the no-use group, the co-use group had a 5.7 times greater odds of having a small head circumference [aOR=5.7 (1.1–28.9)]; 2) occurrence of birth defects, with the co-use group having a 3 times greater odd of having birth defects when compared to the no-use group, aOR=3.1 (1.2–8.3); and 3) stillbirth/miscarriage, with the cannabis only group having 12 times greater odds of a stillbirth or miscarriage compared to the no-use group (aOR=12.1). Stratified analysis by sex of baby for all the outcomes yielded no significant results.

Table 2:

Logistic Regression Modeling of Associations Between Tobacco and Cannabis Couse and Birth Outcomes

No-Use
OR (95% CI)		 Tobacco Cigarettes Only OR (95% CI) Cannabis Only
OR (95% CI)		 Co-Use
OR (95% CI)
Low Birth Weight Ref a 0.7 (0.1–5.4) 2.4 (0.8–7.1) 2.4 (0.6–8.9)
Ref g 0.4 (0.01–13.1) 1.0 (0.1–7.9) 0.7 (0.1–8.6)
Low Birth Length Ref a 0.7 (0.1–5.8) 2.6 (0.9–7.7) 2.6 (0.7–9.6)
Ref f 0.7 (0.01–40.7) 2.0 (0.3–11.9) 1.4 (0.1–14.2)
Small Head Circumference (low vs. normal) Ref a 1.8 (0.4–8.5) 3.0 (1.1–9.1)* 5.5 (1.8–17.3)*
Ref e 4.8 (0.7–34.7) 2.0 (0.4–10.6) 5.7 (1.1–28.9)*
Prematurity
(<37 weeks vs. ≥37 weeks) 		Ref a 0.9 (0.2–4.0) 2.2 (0.9–5.6) 2.1 (0.7–6.6)
Ref d 1.0 (0.2–4.3) 2.2 (0.8–5.6) 1.7 (0.5–5.8)
Low Apgar Score (<7 vs. ≥7) Ref a 2.9 (0.3–26.9) -- 3.0 (0.3–28.1)
Ref i 2.9 (0.3–26.9) -- 0.9 (0.1–8.4)
Stillbirth/Miscarriage Ref a 11.2 (0.7–184.6) 14.3 (1.3–161.5)* 23.4 (2.1–268.0)*
Ref h 12.3 (0.7–205.1) 12.1 (1.03–141.8)* 10.1 (0.8–130.7)
Birth Defects Ref a 1.5 (0.6–3.9) 1.0 (0.4–2.4) 2.4 (0.9–6.0)
Ref b 1.9 (0.7–5.3) 1.2 (0.5–2.9) 3.1 (1.2–8.3)*
NICU Admission Ref a 1.7 (0.6–4.9) 1.5 (0.6–3.6) 1.8 (0.6–5.2)
Ref c 1.7 (0.6–5.0) 1.5 (0.6–3.6) 1.9 (0.7–5.7)
Open in a new tab
a

Unadjusted Model;

b

Adjusted for trimester and marital status;

c

Adjusted for pregnancy intention;

d

Adjusted for maternal age and gravidity;

e

Adjusted for gestational age and race;

f

Adjusted for marital status, trimester of enrolment and gestational age

g

Adjusted for gestational age

h

Adjusted for alcohol use, race and other drug use (opiates, stimulants and benzodiazepines) using propensity score weighted logistic regression. Note wide confidence intervals because of few outcomes (6 total)

i

Adjusted for gestational age and educational status using propensity score weighted logistic regression

*

Statistically significant (α=0.05);

4. Discussion

There are several key findings from this study that highlight the importance of examining cannabis and tobacco co-use during pregnancy. First, in this sample, the prevalence rate of cannabis and tobacco cigarette co-use as well as the prevalence rate of cannabis only use is higher than the prevalence of tobacco cigarette only use, which is notable given the focus on tobacco cessation in clinical practice. This cross-sectional finding of high cannabis prevalence aligns with recent trend studies that have suggested increasing cannabis use and co-use among pregnant women (Brown et al., 2017; Young-Wolff et al., 2017). Based on national survey data collected in 2014, 6% of pregnant women reported past month cannabis use (an increase of 62% from 2002–2014), 15% of pregnant women reported past month cigarette smoking, and 4% of pregnant women reported past month use of both cannabis and tobacco (Brown et al., 2017; USDHHS, 2016). Furthermore, based on national survey data collected between the years of 2005 and 2014, 1.0% of pregnant women reported past month cannabis use, 13.3% of pregnant women reported past month tobacco use, and 3.3% of pregnant women reported past month use of both cannabis and tobacco (Coleman-Cowger et al., 2017). The current study found much higher rates of cannabis use and co-use, and lower rates of tobacco use, relative to these national samples of pregnant women. Possible reasons for these differences include the race and socioeconomic status of this sample, as previous studies have shown higher rates of co-use among socioeconomically disadvantaged African- Americans (Coleman-Cowger et al., 2017; Montgomery, 2015; Montgomery et al., 2017).

Second, an association was found between co-use and smaller head circumference. The average newborn’s head circumference is 35 centimeters. Head circumference is an important marker of fetal brain development (Lipper et al., 1981), and smaller head circumference has been associated with cognitive impairment (Webb et al., 2001). Tobacco smoking has previously been associated with small head circumference (Källén, 2000), but co-use may confer additional harm. Cannabis use was not associated with having a low birth weight baby, which supports previous inconclusive findings in the literature (English et al., 1997). There are multiple possible physiologic explanations for these findings, including difference in placentation caused by vasospasm or vascular changes, nutritional differences of the mother, or underlying factors that are related to both tobacco and cannabis use such as stress or mental health disorders (Lipper et al., 1981).

Screening for cannabis use during pregnancy is not as common as screening for prenatal tobacco use, despite the fact that cannabis use was more common than tobacco cigarette use in our study population. Greater focus on the possible health implications that may result from cannabis use and co-use is needed. There is currently no formal recommendation for screening or intervention with cannabis and tobacco co-use during pregnancy. This is an unfortunate missed opportunity, given (a) emerging evidence that simultaneous cessation of both tobacco and cannabis may yield benefits at both the psychological and neurobiological level (Rabin and George, 2015) and (b) acknowledgement within the research community that women with a history of both cannabis and tobacco dependence are a vulnerable sub-group of users who need more specialized treatment during the perinatal period to improve (Emery et al., 2016). Interventions adapted to address concurrent cannabis and tobacco use in the general population have shown initial efficacy (Becker et al., 2014; Becker et al., 2013; Gulliver et al., 2015; Lee et al., 2015), yet none have specifically been developed to address the unique needs of a pregnant population. In one study, approximately 70% of pregnant and non-pregnant women believed there was “slight” or “no risk” of harm from using cannabis once or twice a week (Ko et al., 2015). Moreover, health professionals may not be addressing co-use in pregnancy as a serious concern. Another study of obstetric health care providers found that when cannabis use was disclosed to them, nearly half (48%) did not follow up on the disclosures or offer counseling. In the minority of cases, when counseling was offered, it consisted of general statements about cannabis without specific information on the risks or outcomes related to cannabis use in pregnancy or on the neonatal health effects (Holland et al., 2016). The American College of Obstetricians and Gynecologists (ACOG) recommends that women who report marijuana use “should be counseled about concerns regarding potential adverse health consequences of continued use during pregnancy” and encouraged to discontinue use (ACOG, 2017). There is a need for guidance on how to counsel when findings on the health effects of cannabis are limited and sometimes conflicting.

Finally, there is a continued need to focus on African-American women and reducing the health disparities that exist within this population (Dominguez, 2011; Martin and Montagne, 2017). A large percentage of participants reported a stillbirth or miscarriage in a previous pregnancy, regardless of substance use. Social and environmental factors, such as perceived racism and discrimination and stress, need to be considered in research examining how best to intervene with a pregnant African-American population. A recent meta-analysis of cannabis use treatments for African-Americans found no articles available on cannabis use treatment with a 100% African American sample and this is an area worthy of further exploration (Montgomery et al., 2017).

This is one of the first studies to examine co-use of cannabis and tobacco during pregnancy and associated birth outcomes. Despite several noteworthy strengths, it is not without limitations. Though the overall sample was large, this study had limited power and could not predict birth outcomes by use groups. Instead, the focus was descriptive and adds foundational knowledge upon which future research can be built. In the same vein, detailed data was not collected on use patterns over time, tobacco or cannabis product type, or reasons for use. Future research should, for example, collect data on potency of cannabis used and mode of use (i.e., combusted vs. vaporized for tobacco, and combusted vs. vaporized vs. edible for cannabis), to elucidate understanding of how these factors may differentially impact health outcomes. Future research should also collect data on detailed use patterns, such as frequency and quantity, using standardized measures to investigate whether there may be a dose- dependent relation between substance use frequency and birth outcomes. Finally, trimester of substance exposure should also be considered in future research in this area.

The examination of cannabis and tobacco co-use during pregnancy among marginalized, vulnerable populations with relatively high use prevalence is a highly significant endeavor, particularly as cannabis use, its potency, and availability in the US have increased in recent years. Additional research is needed to better understand how factors such as potency, reasons for use, modes of use, trimester of exposure, and contextual/environmental cues may moderate the relationship between co-use and health outcomes for both mother and child.

Highlights.

  • Pregnant women co-use cannabis and tobacco cigarettes at high rates.

  • Cannabis use rates were higher than tobacco use rates in our sample.

  • Smaller head circumference and birth defects were associated with maternal co-use.

  • Interventions addressing prenatal co-use and cannabis use are warranted.

Acknowledgments

The research reported in this article is supported by the National Institute on Drug Abuse (NIDA) of the National Institutes of Health (NIH) grant under Award Number R01DA041328 (PI-Coleman-Cowger). The content is solely the responsibility of the authors and does not represent the official views of the National Institutes of Health.

Footnotes

Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Contributor Information

Victoria H. Coleman-Cowger, Battelle Memorial Institute

Emmanuel Oga, Battelle Memorial Institute.

Erica N. Peters, Battelle Memorial Institute

Katrina Mark, Department of Obstetrics, Gynecology and figure Reproductive Sciences, University of Maryland School of Medicine.

References

  1. Agrawal A, Budney AJ, Lynskey MT, 2012. The co-occurring use and misuse of cannabis and tobacco: a review. Addiction 107(7), 1221–1233. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Agrawal A, Lynskey MT, 2009. Tobacco and cannabis co-occurrence: does route of administration matter? Drug and alcohol dependence 99(1), 240–247. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Becker J, Haug S, Sullivan R, Schaub MP, 2014. Effectiveness of different web-based interventions to prepare co-smokers of cigarettes and cannabis for double cessation: a three-arm randomized controlled trial. Journal of medical Internet research 16(12). [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Becker J, Hungerbuehler I, Berg O, Szamrovicz M, Haubensack A, Kormann A, Schaub MP, 2013. Development of an integrative cessation program for co-smokers of cigarettes and cannabis: demand analysis, program description, and acceptability. Substance abuse treatment, prevention, and policy 8(1), 33. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Brown QL, Sarvet AL, Shmulewitz D, Martins SS, Wall MM, Hasin DS, 2017. Trends in marijuana use among pregnant and nonpregnant reproductive-aged women, 2002–2014. Jama 317(2), 207–209. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Budney AJ, Borodovsky JT, 2017. The potential impact of cannabis legalization on the development of cannabis use disorders. Preventive medicine. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cepeda MS, Boston R, Farrar JT, Strom BL, 2003. Comparison of logistic regression versus propensity score when the number of events is low and there are multiple confounders. American Journal of Epidemiology, v. 158, n.3, p. 280–287. [DOI] [PubMed] [Google Scholar]
  8. Chasnoff I, Wells A, McGourty R, Bailey L, 2007. Validation of the 4P’s Plus© screen for substance use in pregnancy validation of the 4P’s Plus. Journal of Perinatology 27(12), 744. [DOI] [PubMed] [Google Scholar]
  9. Coleman-Cowger VH, Oga EA, Peters EN, Trocin K, Koszowski B, Mark K, 2018. Comparison and validation of screening tools for substance use in pregnancy: a cross-sectional study conducted in Maryland prenatal clinics. BMJ Open 8(2), e020248. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Coleman-Cowger VH, Schauer GL, Peters EN, 2017. Marijuana and tobacco co-use among a nationally representative sample of US pregnant and non-pregnant women: 2005–2014 National Survey on Drug Use and Health findings. Drug and Alcohol Dependence. [DOI] [PubMed] [Google Scholar]
  11. Dominguez TP, 2011. Adverse Birth Outcomes in African American Women: The Social Context of Persistent Reproductive Disadvantage. Social Work in Public Health 26(1), 3–16. [DOI] [PubMed] [Google Scholar]
  12. El Marroun H, Tiemeier H, Jaddoe VW, Hofman A, Mackenbach JP, Steegers EA, Verhulst FC, van den Brink W, Huizink AC, 2008. Demographic, emotional and social determinants of cannabis use in early pregnancy: the Generation R study. Drug and alcohol dependence 98(3), 218–226. [DOI] [PubMed] [Google Scholar]
  13. Emery RL, Gregory MP, Grace JL, Levine MD, 2016. Prevalence and correlates of a lifetime cannabis use disorder among pregnant former tobacco smokers. Addictive behaviors 54, 52–58. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. English D, Hulse G, Milne E, Holman C, Bower C, 1997. Maternal cannabis use and birth weight: a meta-analysis. Addiction 92(11), 1553–1560. [PubMed] [Google Scholar]
  15. Fried PA, Makin J, 1987. Neonatal behavioural correlates of prenatal exposure to marihuana, cigarettes and alcohol in a low risk population. Neurotoxicology and teratology 9(1), 1–7. [DOI] [PubMed] [Google Scholar]
  16. Giglia RC, Binns CW, Alfonso HS, Zhan Y, 2007. Which mothers smoke before, during and after pregnancy? Public Health 121(12), 942–949. [DOI] [PubMed] [Google Scholar]
  17. Gulliver A, Farrer L, Chan JK, Tait RJ, Bennett K, Calear AL, Griffiths KM, 2015. Technology- based interventions for tobacco and other drug use in university and college students: a systematic review and meta-analysis. Addiction science & clinical practice 10(1), 5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Gunn JKL, Rosales CB, Center KE, Nuñez A, Gibson SJ, Christ C, Ehiri JE, 2016. Prenatal exposure to cannabis and maternal and child health outcomes: a systematic review and meta-analysis. BMJ Open 6(4). [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Hasin DS, Saha TD, Kerridge BT, Goldstein RB, Chou SP, Zhang H, Jung J, Pickering RP, Ruan WJ, Smith SM, 2015. Prevalence of marijuana use disorders in the United States between 2001–2002 and 2012–2013. JAMA psychiatry 72(12), 1235–1242. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Havens JR, Simmons LA, Shannon LM, Hansen WF, 2009. Factors associated with substance use during pregnancy: results from a national sample. Drug and alcohol dependence 99(1), 89–95. [DOI] [PubMed] [Google Scholar]
  21. Holland CL, Rubio D, Rodriguez KL, Kraemer KL, Day N, Arnold RM, Chang JC, 2016. Obstetric health care providers’ counseling responses to pregnant patient disclosures of marijuana use. Obstetrics and gynecology 127(4), 681. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Ko JY, Farr SL, Tong VT, Creanga AA, Callaghan WM, 2015. Prevalence and patterns of marijuana use among pregnant and nonpregnant women of reproductive age. American journal of obstetrics and gynecology 213(2), 201. e201–201. e210. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Källén K, 2000. Maternal smoking during pregnancy and infant head circumference at birth. Early human development 58(3), 197–204. [DOI] [PubMed] [Google Scholar]
  24. Lee DC, Budney AJ, Brunette MF, Hughes JR, Etter J-F, Stanger C, 2015. Outcomes from a computer-assisted intervention simultaneously targeting cannabis and tobacco use. Drug and alcohol dependence 155, 134–140. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Lipper E, Lee K, Gartner LM, Grellong B, 1981. Determinants of neurobehavioral outcome in low- birth-weight infants. Pediatrics 67(4), 502–505. [PubMed] [Google Scholar]
  26. Martin N, Montagne R, 2017. Black Mothers Keep Dying After Giving Birth. Shalon Irving’s Story Explains Why. https://www.npr.org/2017/12/07/568948782/black-mothers-keep-dying-after-giving- birth-shalon-irvings-story-explains-why. (Accessed 12/31/2017 2017).
  27. Montgomery L, 2015. Marijuana and tobacco use and co-use among African Americans: results from the 2013, National Survey on Drug Use and Health. Addictive behaviors 51, 18–23. [DOI] [PubMed] [Google Scholar]
  28. Montgomery L, Robinson C, Seaman EL, Haeny AM, 2017. A scoping review and meta-analysis of psychosocial and pharmacological treatments for cannabis and tobacco use among African Americans. Psychology of Addictive Behaviors 31(8), 922. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Ng M, Freeman MK, Fleming TD, et al. , 2014. Smoking prevalence and cigarette consumption in 187 countries, 1980–2012. JAMA 311(2), 183–192. [DOI] [PubMed] [Google Scholar]
  30. NIoD A, 2011. Screening for drug use in general medical settings: resource guide. Updated version. NlDA. [Google Scholar]
  31. Peters E, Pancholi C, Coleman-Cowger V, Koszowski B, Pickworth W, 2016. How do tobacco and marijuana interact to influence the health consequences of smoking? A systematic and critical review of the literature., Society for Research on Nicotine and Tobacco Annual Meeting. Chicago, IL. [Google Scholar]
  32. Peters EN, Budney AJ, Carroll KM, 2012. Clinical correlates of co-occurring cannabis and tobacco use: A systematic review. Addiction 107(8), 1404–1417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Rabin RA, George TP, 2015. A review of co-morbid tobacco and cannabis use disorders: Possible mechanisms to explain high rates of co-use. The American journal on addictions 24(2), 105–116. [DOI] [PubMed] [Google Scholar]
  34. Ramo DE, Liu H, Prochaska JJ, 2012. Tobacco and marijuana use among adolescents and young adults: A systematic review of their co-use. Clinical Psychology Review 32(2), 105–121. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Richardson GA, Ryan C, Willford J, Day NL, Goldschmidt L, 2002. Prenatal alcohol and marijuana exposure: effects on neuropsychological outcomes at 10 years. Neurotoxicology and teratology 24(3), 309–320. [DOI] [PubMed] [Google Scholar]
  36. Schauer GL, Berg CJ, Kegler MC, Donovan DM, Windle M, 2015. Assessing the overlap between tobacco and marijuana: Trends in patterns of co-use of tobacco and marijuana in adults from 2003–2012. Addictive Behaviors 49(Supplement C), 26–32. [DOI] [PubMed] [Google Scholar]
  37. Schulenberg J, Johnston L, O’Malley P, Bachman J, Miech R, Patrick M, 2017. Monitoring the Future national survey results on drug use, 1975–2016: Volume II, college students and adults ages 19–55. [Google Scholar]
  38. Smith PC, Schmidt SM, Allensworth-Davies D, Saitz R, 2010. A single-question screening test for drug use in primary care. Archives of Internal Medicine 170(13), 1155–1160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. U.S. Department of Health and Human Services. The Health Consequences of Smoking: 50 Years of Progress. A Report of the Surgeon General. Atlanta, GA: U.S: Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. Printed with corrections, January 2014. [Google Scholar]
  40. U.S. Department of Health and Human Services. Substance Abuse and Mental Health Services Administration. Center for Behavioral Health Statistics and, Q, 2016. National Survey on Drug Use and Health, 2014. Inter-university Consortium for Political and Social Research (ICPSR) [distributor].
  41. Volkow ND, Baler RD, Compton WM, Weiss SR, 2014. Adverse health effects of marijuana use. New England Journal of Medicine 370(23), 2219–2227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Webb SJ, Monk CS, Nelson CA, 2001. Mechanisms of postnatal neurobiological development: implications for human development. Developmental neuropsychology 19(2), 147–171. [DOI] [PubMed] [Google Scholar]
  43. World Health Organization, 2015. WHO global report on trends in prevalence of tobacco smoking 2015. World Health Organization. [Google Scholar]
  44. World Health Organization, 2016. The health and social effects of nonmedical cannabis use, The health and social effects of nonmedical cannabis use. World Health Organization. [Google Scholar]
  45. World Health Organization, 2017. Tobacco Fact Sheet. http://www.who.int/mediacentre/factsheets/fs339/en/. (Accessed December 30, 2017).
  46. Yonkers KA, Gotman N, Kershaw T, Forray A, Howell HB, Rounsaville BJ, 2010. Screening for prenatal substance use: development of the Substance Use Risk Profile-Pregnancy scale. Obstetrics and gynecology 116(4), 827. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Young-Wolff KC, Tucker L, Alexeeff S, et al. , 2017. Trends in self-reported and biochemically tested marijuana use among pregnant females in california from 2009–2016. JAMA 318(24), 2490–2491. [DOI] [PMC free article] [PubMed] [Google Scholar]

RESOURCES