Association of psychiatric and substance use disorders with cannabis use and cannabis use disorder during early pregnancy in northern California.

AIMS: To estimate the strength of association between psychiatric disorders and substance use disorders (SUD), and cannabis use and cannabis use disorder (CUD) during early pregnancy. DESIGN: Observational study. SETTING: Kaiser Permanente Northern California, USA. PARTICIPANTS: 299 496 pregnancies from 227 555 individuals screened for cannabis use by self-report and a urine toxicology test at entrance to prenatal care in Kaiser Permanente Northern California during January 2011-December 2021 (excepting year 2020). The sample was 62.5% non-White, with a mean (standard deviation) age of 31.1 (5.5) years; 6.8% used cannabis; 0.2% had a CUD. MEASUREMENTS: Exposure variables included electronic health record-based psychiatric diagnoses of attention deficit hyperactivity, anxiety, bipolar, depressive, personality, posttraumatic stress and psychotic disorders; and alcohol, opioid, stimulant and tobacco use disorders, during the two years prior to pregnancy up to the day before the prenatal substance use screening date. Outcome variables were any cannabis use, frequency of self-reported cannabis use and CUD during early pregnancy. FINDINGS: Psychiatric disorder prevalence ranged from 0.2% (psychotic) to 14.3% (anxiety), and SUD ranged from 0.3% (stimulant/opioid) to 3.8% (tobacco). Psychiatric disorders were associated with cannabis use and CUD, with the strongest association for any use found for bipolar disorder (adjusted odds ratio [aOR] = 2.83; 95% confidence interval [CI] = 2.53-3.17) and the strongest association for CUD found for psychotic disorders (aOR = 10.01, 95% CI = 6.52-15.37). SUDs were associated with cannabis use and CUD, with the strongest association for any use found for tobacco use disorder (aOR = 4.03, 95% CI = 3.82-4.24) and the strongest association for CUD found for stimulant use disorder (aOR = 21.99, 95% CI = 16.53-29.26). Anxiety, bipolar, depressive disorders and tobacco use disorder were associated with greater odds of daily than monthly or less cannabis use. CONCLUSIONS: Psychiatric disorders and substance use disorders appear to be associated with elevated odds of any and frequent cannabis use as well as cannabis use disorder during early pregnancy. In most cases, the associations with cannabis outcomes were stronger for substance use disorders than other psychiatric disorders.

Intentions to Use Cannabis Postpartum: A Qualitative Study of Pregnant Individuals Who Used Cannabis During Early Pregnancy.

Objective: To examine plans for postpartum cannabis use among pregnant individuals who used cannabis during early pregnancy. Materials and Methods: Eighteen virtual focus groups were conducted from November 17, 2021, to December 17, 2021, with 23 Black and 30 White pregnant adults in Kaiser Permanente Northern California, who self-reported prenatal cannabis use during early pregnancy. Focus groups were recorded, transcribed, and analyzed using thematic analysis. Results: The sample (N = 53) had a mean age of 30.3 years (standard deviation = 5.2) at recruitment; 70% reported daily, 25% weekly, and 6% ≤ monthly cannabis use at entrance to prenatal care. Some participants viewed cannabis as critical for coping with postpartum mental and physical health challenges, while others questioned whether cannabis use would fit with their parental lifestyle, and some planned to abstain altogether. Most planned to use cannabis postpartum, but with lower frequency than before pregnancy, and in ways consistent with harm reduction (e.g., smoking outside to avoid secondhand or thirdhand smoke exposure). Many were motivated to abstain from cannabis while breastfeeding, and some desired more data on the safety of cannabis and breastfeeding, or intended to "pump and dump," believing it would reduce potential transfer of Δ9-tetrahydrocannabinol (THC) to their infant. Responses from Black and White participants were generally similar, but White participants were more likely to report plans to use cannabis while breastfeeding and to want information about cannabis and breastfeeding. Conclusions: Pregnant individuals with prenatal cannabis use had varied plans for cannabis use postpartum. Many were motivated to abstain or use cannabis less frequently than pre-pregnancy, especially during lactation.

Exploring preferences for different modes of cannabis use during early pregnancy: A qualitative study.

OBJECTIVE: Rates of prenatal cannabis use are rising, yet little is known about modes of cannabis use during pregnancy. This focus group study with pregnant individuals aimed to examine use patterns and perceptions regarding common modes of prenatal cannabis use. METHOD: Kaiser Permanente Northern California pregnant adult patients who identified as White or Black and self-reported cannabis use during pregnancy were recruited to participate (N = 53; 40% Black, 60% White; Meanage = 30.3, SD = 5.2). Eighteen focus groups with race-concordant facilitators followed a semi-structured format that queried participants on their prenatal cannabis use, including preferred modes of use (e.g., vapes, blunts, dabs, joints, edibles, topicals, pipes). Focus group discussions were coded and analyzed using a general inductive approach. RESULTS: A range of modes were preferred, with no single mode predominant. Participants' preferences aligned with four themes: perceived effects and benefits of cannabis, health and safety, convenience and familiarity, and partner and friend influences. Participants sought modes that were accessible and familiar, provided consistent and quick relief for pregnancy-related symptoms, were aligned with partners or friends, and minimized perceived risks while also providing symptom relief. Participants desired evidence-based information about mode safety to better inform mode selection during pregnancy. CONCLUSIONS: A range of personal and social factors influenced mode preferences during pregnancy. Many participants desired to reduce harms and use cannabis more safely in pregnancy but received little mode-specific information to guide these preferences. Further research identifying mode-specific risks is needed to guide harm reduction approaches during pregnancy.

Pregnant individual's lived experience of cannabis use during the COVID-19 pandemic: a qualitative study.

Introduction: Quantitative studies indicate that the COVID-19 pandemic has contributed to increased rates of prenatal cannabis use. However, little is known about how the pandemic has impacted cannabis use from the perspective of pregnant individuals themselves. Our objective was to characterize COVID-19-related changes in cannabis use among pregnant individuals who used cannabis during the pandemic. Methods: We conducted 18 focus groups (from 11/17/2021 to 12/17/2021) with Black and White pregnant individuals aged 18+ who self-reported prenatal cannabis use during universal screening at entrance to prenatal care (at ~8 weeks gestation) in Kaiser Permanente Northern California. Virtual focus groups were transcribed and analyzed using thematic analysis. Results: The sample of 53 pregnant individuals (23 Black, 30 White) was 30.3 years old (SD = 5.2) on average, and most (70%) self-reported daily versus weekly or monthly prenatal cannabis use. Major themes regarding the impact of the pandemic on cannabis use included increases in use (resulting from depression, anxiety, stress, boredom), and changes in social use (less sharing of smoked cannabis products), modes of use (from smoking to other modes due to respiratory concerns) and source (from storefront retailers to delivery). Conclusion: Coping with mental health symptoms and stress were identified drivers of perceived pandemic-related increases in prenatal cannabis use in 2021. Pregnant individuals adapted their use in ways consistent with public health recommendations to decrease social contact and reduce or quit smoking to mitigate COVID-19 transmission and harms. Proactive, mental health outreach for pregnant individuals during future pandemic waves may reduce prenatal cannabis use.

Maternal pregnancy loss, birth characteristics, and childhood leukemia (United States).

OBJECTIVE: The authors evaluated the relation between maternal pregnancy loss, birth characteristics, and childhood leukemia in the Northern California Childhood Leukemia Study. METHODS: Incident cases of childhood leukemia (age 0-14 years) were rapidly ascertained, and controls were randomly selected from birth records and individually matched to cases. A total of 366 cases [313 acute lymphoblastic leukemia (ALL) and 53 acute myeloid leukemia (AML)] and 460 controls were included in this analysis. The biological mothers of all subjects provided detailed reproductive history and birth characteristics of the index children during a personal interview. Odds ratio (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. Data on maternal pregnancy loss and birth characteristics were also available from the birth certificates of 96.3% of all subjects. RESULTS: History of miscarriage was associated with a significantly increased risk of AML (OR = 2.94, 95% CI: 1.03, 8.34), but not ALL. Neither birth weight, birth order, or parental ages appeared to be an important predictor of the risk of ALL or AML. A comparison between data from two different sources (interview versus birth certificate) indicated good reproducibility and offered some evidence against recall bias. CONCLUSION: Maternal history of miscarriage is associated with an increased risk of childhood AML.

Ethnic difference in daycare attendance, early infections, and risk of childhood acute lymphoblastic leukemia.

A role for infectious agents has been proposed in the etiology of childhood acute lymphoblastic leukemia (ALL), particularly for common ALL (c-ALL; ALL diagnosed in children ages 2-5 years and expressing CD10 and CD19 surface antigens). We evaluated the possible etiologic role of daycare attendance (a proxy measure for exposure to infectious agents) and infections during infancy in the Northern California Childhood Leukemia Study. A total of 294 incident ALL cases (ages 1-14 years) and 376 individually matched controls were included in this analysis. In non-Hispanic White children, daycare attendance measured by child-hours was associated with a significantly reduced risk of ALL. Compared with children who did not attend any daycare, the odds ratio (OR) for those who had >5,000 child-hours during infancy was 0.42 [95% confidence interval (95% CI), 0.18-0.99] for ALL and 0.33 (95% CI, 0.11-1.01) for c-ALL. Test for trend is also significant, which supports a dose-response relationship. The magnitude of effect associated with the same number of child-hours was stronger for daycare attendance during infancy than for daycare attendance before diagnosis. In addition, self-reported ear infection during infancy was associated with a significantly reduced risk of c-ALL (OR, 0.32; 95% CI, 0.14-0.74) in non-Hispanic White children. In Hispanic children, no association was observed among daycare attendance, early infections, and risk of childhood ALL or c-ALL. These results offer indirect yet strong support for the infectious disease hypothesis in the etiology of ALL in non-Hispanic White children and highlight an important ethnic difference.

Vaccination history and risk of childhood leukaemia.

BACKGROUND: Previous studies on vaccination and childhood leukaemia generated inconsistent results. METHODS: In the Northern California Childhood Leukaemia Study, a case-control study with incident cases and matched birth certificate controls, detailed written vaccination records were collected. A total of 323 cases aged 0-14 years at diagnosis and 409 controls were included in this analysis. All vaccinations were censored on the reference date (date of diagnosis for cases and the corresponding date for matched controls). Conditional logistic regression analysis was conducted, adjusting for potential confounding factors. A primary variable of interest is the number of administrations (doses) of various types of vaccines. RESULTS: Vaccinations against diphtheria, pertussis, tetanus, poliomyelitis, measles, mumps, and rubella were not associated with the risk of leukaemia. The odds ratio for each dose of Haemophilus influenzae type b (Hib) vaccine was 0.81 (95% CI 0.68-0.96). Compared with children who received two or fewer doses of Hib vaccine, those who received three or more doses had a significantly reduced risk of childhood leukaemia (odds ratio = 0.55, 95% confidence interval 0.32-0.94). The number of doses of hepatitis B vaccine received was not associated with leukaemia risk. CONCLUSIONS: Hib vaccination is associated with a reduced risk of childhood leukaemia. Future studies with detailed exposure assessment and large sample sizes are needed to further address the role of vaccinations in the etiology of childhood leukaemia.

Control selection strategies in case-control studies of childhood diseases.

To address concerns regarding the representativeness of controls in case-control studies, two selection strategies were evaluated in a study of childhood leukemia, which commenced in California in 1995. The authors selected two controls per case: one from among children identified by using computerized birth records and located successfully, the other from a roster of friends; both were matched on demographic factors. Sixty-four birth certificate-friend control pairs were enrolled (n = 128). Additionally, 192 "ideal" controls were selected without tracing from the birth records. Data on parental ages, parental education, mother's reproductive history, and birth weight were obtained from the birth certificates of all 320 subjects. For all variables except birth weight, the differences between birth certificate and ideal controls were smaller than those between friend and ideal controls. None of the differences between birth certificate and ideal controls was significant, whereas two factors were significantly different between friend and ideal controls. These findings suggest that friend controls may be less representative than birth certificate controls. Despite difficulty in tracing and a seemingly low participation rate (49.0% for 560 enrolled birth certificate controls), using birth records to recruit controls appears to provide a representative sample of children and an opportunity to assess the representativeness of controls.