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. 2023 Aug 4;7:19. doi: 10.18332/ejm/168727

Table 3.

Characteristics of studies investigating the relationship between cannabis use in pregnancy and effects on the fetus, the newborn and on later childhood

Study Year Country Type of study Population (characteristics of participants) Report (measurement) Outcome Results Significance p Adjustments for confounding agents
Linn et al.9 1983 Boston USA Retrospective cohort study 12825 women/2529 of them admitted to being cannabis users during pregnancy Postpartum interview Newborns had:

  1. Lower birth weight

  2. Severe malfunctions

  3. Lower Apgar score at 1 minute

 OR=1.36 for serious malfunctions
OR=1.07 for low birth weight		 0.001
<0.05		 Excluded women who reported drug use
Fried10 1995 Ottawa Ontario Canada Prospective study 700 women surveyed in pregnancy Interview during pregnancy in each trimester Newborns had increased tremor, lower visual acuity
At the age of 4 years experienced memory problems		 - - -
Gray et al.11 2010 USA Retrospective cohort study 120 pregnant women
12–20 weeks

  1. Interview in each trimester with the completion of a questionnaire

  2. Examination of oral smear

  3. Collection of meconium

  4. from newborns

 Newborns had:

  1. Lower birth weight

  2. Lower head circumference

  3. Younger birth age

  1. Low birth weight

  2. Shorter week of gestation

  3. Shorter head circumference

  4. Short body length

 <0.051
<0.685
<0.011
<0.156		 There had to be a positive test in more than 1 measurement/day of a random sample of meconium.
The degree of effect of the fetus with the parallel use of tobacco and cannabis of the mother has a negative outcome.
El Maroun et al.12 2010 Netherlands Cohort study 5512 children/4077 of them for behavioral problems at the age of 18 months Questionnaire in the 1st trimester even for use by the partner and examination of a urine sample Girls had an increased chance of aggressive behavior and concentration problems OR=1.66 for aggressive behaviors in girls
OR=2.75 for concentration matters		 p=0.50 for aggressive behavior
p=0.01 for concentration problems		 Socioeconomic factors, sometimes cannabis use was combined with tobacco use.
Day et al.7 2011 USA Longitudinal, cohort study 1360 women were selected and their children Interview in their fourth prenatal month, seventh prenatal month at delivery, 8, and 18 months, and 3, 6,10, 14, 16, and 22 years postpartum. At birth, there were 763 live-born singleton infants.

  1. Depressive symptoms

  2. Attention problems

  3. Learning and memory problems

Delinquency at the age of 14		 <0.001
<0.01
<0.01
<0.01		 Socioeconomic factors such as household income, home environment etc.
Hayatbakhsh et al.5 2011 Australia Cohort study 24874 women who gave birth between 2000–2006 Interview in pregnancy The newborns:

  1. Lower birth weight

  2. Premature

  3. Residual growth

  4. Higher chance of going into an Increased Care Unit

  1. ΟR=2.4

  2. OR=1.7

  3. OR=3.1

  4. OR=2.3

 <0.001 The age of the mother as well as socioeconomic factors
Leemaqz et al.13 2015 Australia New Zealand Ireland UK Cohort study Women who gave birth between November 2004 and February 2011 Asked about cannabis use during the 15th and 20th week of gestation

  1. Prematurity

  2. Residual growth

 OR=2.31 (95% CI: 1.45–3.55) for prematurity
OR=1.37 (95% CI: 0.96–1.92) for newborns with residual growth		 <0.001 for prematurity <0.005 for newborns young Others factors affecting outcome of pregnancy such as PCOS are not included
Salzwedel et al.14 2015 Chatham Orange Durham Alamance North Carolina USA Prospective study Newborns were studied in 3 categories Underwent an rsfMRI test Abnormal functionality of the amygdala and the islet of the brain of the newborn - <0.05–0.001 Cannabis use was associated with education level and the socioeconomic level
Fransquet et al.15 2016 Australia Cohort study Study of 1634 women

  1. Questionnaires in pregnancy and after childbirth

  2. DNA study in neon after swabbing at 8 weeks of life

  1. DNA methylation in CpG.32 position in newborns exposed to cannabis

  2. Methylation in CpG.21.22.23 along with tobacco use

 95% CI: 0.11–1.46%
95% CI: 0.02–2.93%		 p=0.069 in exclusive use of cannabis
p=0.40 with tobacco use		 Difficult to separate the effects on the newborn that come exclusively from the use of cannabis.
Crume et al.16 2018 Colorado USA Cross-sectional
study		 Women who gave birth from 1/1/2014 to 31/12/2015 in Colorado Interview by phone and questionnaires, up to 2 months after giving birth

  1. Low birth weight

  2. Prematurity

  3. Hospitalization in neonatal units

  4. Young for birth age newborns

 OR=1.8 0.0008
0.2
0.9
0.03

  1. Medical history in pregnancy

  2. Education level

  3. Nationality

  4. Age

  5. Socioeconomic level
Eiden et al.8 2018 USA Prospective
study		 247 mother-infant dyads 1. Prenatal assessments were conducted once in each trimester of pregnancy
2. A phone interview at 3 years of child age
3. Maternal interviews and infant saliva samples at 2, 9, 16 months, and visits at 2 years		 1. Girls in the control group were breastfed longer
2. At 2 years, higher first trimester cannabis use was associated with higher symptoms of anxiety/depression
3. Girls with positive meconium for cannabis had fewer sleep problems		 <0.07
<0.05		 The sample overall consisted primarily of young, unmarried, lowincome, minority women with low education.
Corsi et al.17 2019 Ontario Canada Retrospective cohort study Women >15 years who gave birth to 1 newborn (>20 weeks) in Ontario from 1/4/2012 to 31/12/2017 Asked about cannabis use in routine pregnancy screening

  1. Childbirth before 37 weeks

  2. Residual growth

  3. Stillbirth

  4. Transfer to an Increased Care Unit, lower Apgar score in the 5th minute

 95% CI: 5.22–6.54% <0.001 Many women out of fear concealed the use. There may be risk factors which are not included.
Sturrock et al.18 2019 UK Cohort study 4465 children born from 1/8/2017 to 31/7/2018 Information about:

  1. Habits in pregnancy

  2. Socioeconomic level

  3. Race

  4. The possible hospitalization of newborns in Intensive Care Units

 Newborns:

  1. Less birth weight

  2. Lower head circumference

 95% CI: (-0.989 vs -0.587) body weight 95% CI: (-1.33 vs 0.782) head circumference p=0.028 for birth weight
p=0.025 for head circumference		 -