Given the mixed literature regarding associations between cannabis use and anxiety , future research should test a wider range of NA items and study their potential differential association with cannabis use. Future studies are needed to test if our results generalize to other student populations and jurisdictions. The observed cannabis-affect associations may also depend on the mode of cannabis administration and tetrahydro cannabinol versus Cannabidiol concentrations . Despite participants indicating they smoked cannabis joints, we did not include detailed momentary assessments on methods of use and product. A controlled cannabis intoxication study including manipulation by THC/CBD concentration and mode of administration could add essential information to the mechanisms of cannabis use. As of yet, there is only limited evidence that CBD alters THC’s effects on mood . We did not measure expectancies, motivation or social context of use, which may be important moderating and mediating factors of the relationships between cannabis use and mood . Medical use is probably uncommon in our sample as it is generally associated with older age groups, and compared to other countries the number of registered medical cannabis users is low in the Netherlands .
Finally, while this study answers a general call to include momentary questions regarding amount used , cannabis grow tray the measure may be unreliable . Since the focus was on within-subject differences, it is, however, expected that any related bias should be minimal; while there may be differences between individuals’ visual estimates of a gram of cannabis, the estimates are likely to be similar within the individual. Tobacco and cannabis use during pregnancy are a major public health problem . Pregnancy tobacco and cannabis use are associated with adverse perinatal outcomes including placenta abruption, abortion, fetal growth restriction, preterm, small for gestational age and low birth weight . Paradoxically, previous studies reported that maternal tobacco use during pregnancy is associated with a lower risk of preeclampsia . In contrast, co-use of cannabis and tobacco during pregnancy seems to be associated with a higher risk of preeclampsia . Early placental vascularization and development may be involved in the relation of tobacco and cannabis use with pregnancy outcomes . Maternal smoking during pregnancy may impair the placental development altering its proliferation, differentiation and structure . Early vascular placentation development is regulated by both soluble fms-like tyrosine kinase-1 as an anti-angiogenic and placental growth factor as a pro-angiogenic factor . The imbalance between these anti- and pro-angiogenic factors seems to be associated with pregnancy complications, including preeclampsia, fetal growth restriction and preterm . Cannabis exposure may affect early placentation process by compromising the trophoblastic migration through the endocannabinoid system .
Additionally, a recent study showed that preconception tobacco and cannabis use are associated with a higher risk of preterm and low birth weight in offspring, but little is known about the influence on placental development . Based on previous studies, we hypothesized that maternal tobacco and cannabis use are associated with impaired placental development characterized by changes in placental angiogenic markers and placental structure . We examined the associations of maternal tobacco and cannabis use before and during pregnancy with angiogenic factors in a population-based cohort. Angiogenic factors included PIGF and sFIt-1 vertical grow systems for sale. We also examined the associations of maternal tobacco and cannabis use with placental weight, placental weight to birth weight ratio and the risks of pregnancy complications including gestational hypertensive disorders, preterm and small for gestational age . Suboptimal placental development may be caused by an imbalance in angiogenic growth factors and subsequently lead to pregnancy complications . We observed that continued tobacco use during pregnancy produced a pro-angiogenic state, with a lower sFlt-1/PlGF ratio, lower sFlt-1 and higher PlGF concentrations in the second trimester. This is in agreement with previous studies, which reported that continued maternal smoking in pregnancy stimulates pro-angiogenic factors and decreases anti-angiogenic factors, particularly in the first and second trimester . Further, a nested case-control study in the United States among 1323 normotensive nulliparous pregnant women reported that continued maternal tobacco use during pregnancy was associated with lower sFlt-1 and higher PlGF concentrations in the first and second trimester .