Impact of in utero tobacco exposure on fetal growth: Amount of exposure and second trimester fetal growth measurements.

BACKGROUND: Research reveals small and inconsistent findings linking prenatal tobacco exposure and early fetal growth, but failure to consider confounding and amount of exposure many explain inconsistencies. GOAL: To examine whether fetal growth effects following exposure to tobacco are evident in the second trimester, specific to certain growth parameters, and dose dependent. METHODS: Participants were pregnant women (64 smokers, 100 controls) with no other drug use. Available data included background/medical information and ultrasound measurements coded as percentiles. RESULTS: Controlling for background differences, 10+ cig/day predicted a 10+ percentile point reduction in estimated fetal weight, femur length, head circumference, and biparietal diameter compared to non-exposed controls. Exposure to <10 cig/day predicted significant reduction in only biparietal diameter. Exposure was unrelated to abdominal circumference. CONCLUSIONS: Results demonstrate utility of considering amount of exposure when examining/quantifying fetal growth effects, and suggest even reduction in early pregnancy smoking may positively benefit aspects of fetal development.

Birth outcomes following in utero co-exposure to tobacco and marijuana.

BACKGROUND: With recent changes in tobacco and marijuana use patterns, it becomes crucial to understand how the prenatal co-use of these substances impacts birth outcomes. The goal of this study was to examine the risk of adverse birth outcomes among infants born to women who used tobacco and marijuana concurrently throughout pregnancy compared to infants of women who used tobacco alone. METHODS: This study involved a retrospective chart review of pregnant women identified via self-report or biochemical testing who used tobacco products alone (N = 71) or tobacco and marijuana simultaneously (N = 127) at any point throughout pregnancy. Differences in birth outcomes between these groups, including APGAR (appearance, pulse, grimace, activity, and respiration) scores, respiratory distress, neonatal intensive care unit admission, intrauterine growth restriction, birth weight, birth length, head circumference, gestational age, and length of hospital stay, were analyzed using linear regression and odds ratio analysis. RESULTS: There were no significant differences in outcomes for infants of women who used tobacco and marijuana compared to infants of women who used tobacco alone during pregnancy. Rates of adverse birth outcomes were high among women who used tobacco compared to what would be expected in unexposed pregnancies. CONCLUSIONS: Tobacco and marijuana co-use during pregnancy was not associated with an additional risk of adverse birth outcomes compared to tobacco use alone. Women should be educated on potential risks of marijuana, and especially, tobacco use during pregnancy. These results will inform clinical recommendations for pregnant women using tobacco and marijuana, aiming to decrease preventable adverse outcomes for patients and infants.

In utero effects of opioids on fetal growth.

BACKGROUND: Studies indicate antenatal opioid use is associated with birth size deficits, as evidenced by reductions in birth weight and head circumference. However, there remains a limited understanding of how early this growth restriction occurs, and what specific parameters are affected. This novel study evaluated global and specific growth deficits associated with prenatal opioid exposure between 18-22 weeks' gestation as assessed during anatomy ultrasounds. METHODS: Pregnant women who completed an anatomy ultrasound were identified via electronic medical records from a large academic obstetric practice. The study group used opioids, with tobacco and/or marijuana use permitted (n = 41). The control group could have used tobacco and/or marijuana, but not opioids (n = 308). Neither group had alcohol or other drug exposure. Records were reviewed for medical history and ultrasound size parameters, coded as percentiles for gestational age. RESULTS: Demographics and medical histories were compared with several significant differences noted. After controlling for these differences, significant (p < 0.05) growth deficits were identified in opioid-exposed fetuses. Specifically, reductions >10 percentile points were observed in head circumference, biparietal diameter, and humerus length for opioid-exposed fetuses compared to controls. Additionally, intrauterine growth restriction (IUGR) was diagnosed five times more often. Femur length was significantly reduced in opioid-exposed fetuses prior to adjustment for confounding (p = .016), but this reduction was not significant (p = .072) after controlling for background differences. Estimated fetal weight (p = .274) and abdominal circumference (p = .633) were not significantly different between exposure groups. CONCLUSION: Fetal opioid exposure predicted various bone growth deficits during routine anatomy ultrasound, indicating the effects of opioid exposure on size deficits may be evident as early as 18-22 weeks' gestation. These findings may also suggest that in utero opioid exposure negatively impacts bone growth specifically rather than weight or fat/muscle mass. Additional studies with larger sample sizes may also reveal significantly reduced femur length, further supporting a negative impact on bone growth. Future studies evaluating bone health and immune function in children after antenatal opioid exposure may help clarify this specific effect of opioids on bone development.

The impact of timing of in utero marijuana exposure on fetal growth.

Objective: To examine whether timing of in utero marijuana exposure independently and negatively impacts fetal growth, and if these effects are global or specific to certain growth parameters. Study design: The two study groups were marijuana users (N = 109) and a randomly selected control group of biochemically verified non-users (n = 171). Study data were obtained via manual abstraction of electronic medical records. Results: After control for significant confounders, regression results indicated significant (p < .05) decrease in newborn weight following first trimester marijuana exposure only (-154 g) and following marijuana exposure throughout gestation (-185 g) compared to controls. There were also significant deficits in head circumference following marijuana exposure in the first and second trimester only (-.83 cm) and marijuana exposure throughout pregnancy (-.79 cm) compared to controls. Newborn length was not significantly predicted by marijuana exposure. Conclusions: Timing of marijuana exposure appears to play a key role in specific fetal growth deficits, with exposure throughout gestation most detrimental. However even first trimester exposure may result in decreased weight. Timing and amount of use could be confounded in this study as those who quit early in pregnancy may have been lighter users than those who continued throughout pregnancy. More research is clearly needed to better understand the role of amount and timing of in utero marijuana exposure in predicting different aspects of fetal growth, however, this study suggests that women should be encouraged to avoid marijuana use at any point in pregnancy.