Birth Outcomes: The CDC Study
A landmark 2026 CDC study published in the journal Adverse Birth Outcomes Associated With Prepregnancy and Prenatal Electronic Cigarette Use provided the strongest US population-level evidence to date:
| Outcome | Vaping During Pregnancy | Non-Use | Adjusted Risk | Evidence Level |
|---|---|---|---|---|
| Low birth weight (LBW) | 8.1% | 6.1% | PR 1.33 (95% CI: 1.06-1.66) | HIGH |
| Preterm birth (exclusive EC use) | Elevated | Baseline | OR 1.67 (95% CI: 1.11-2.51) | HIGH |
| Small-for-gestational-age (SGA) | Elevated | Baseline | OR 1.73 (95% CI: 1.34-2.22) | HIGH |
| Low birth weight (meta-analysis) | Elevated | Baseline | OR 1.60 (95% CI: 1.23-2.09) | HIGH |
| Preterm birth (meta-analysis) | Elevated | Baseline | OR 1.40 (40% increased risk) | HIGH |
The CDC study noted that e-cigarette use during pregnancy, particularly when used daily by individuals who do not also smoke combustible cigarettes, is associated with adverse birth outcomes. This finding is critical because it means the risk is not simply a smoking effect — vaping alone, without cigarette co-use, still harms birth outcomes.
Neurodevelopmental Effects: Animal Model Evidence
Multiple 2025-2026 animal studies have revealed concerning neurological effects of prenatal nicotine exposure from e-cigarettes:
| Effect | Finding | Persistence | Evidence Level |
|---|---|---|---|
| Short-term memory deficits | Nicotine exposure (50 mg/mL e-liquid) caused memory impairment | Observed at 6 and 12 months in offspring | MODERATE |
| Spatial memory impairment | High-dose prenatal nicotine diminished spatial memory, dose-dependent | Most robust in female offspring | MODERATE |
| Attention deficits | Negative effects on attention-related tasks | Dose-dependent, sex-dependent | MODERATE |
| Neuronal damage | Evidence of neuronal damage and increased astrocyte-endothelial interaction | Observed at 6-12 months | MODERATE |
| Altered gene expression | Clock genes, antioxidant pathways, decreased sirtuin-1 expression | Measured in brain tissue | MODERATE |
| Craniofacial development | Negative impact on newborn craniofacial development | Observable at birth | MODERATE |
Important caveat: These neurodevelopmental findings come from animal models (mice/rats). While animal studies are a critical first step in understanding developmental toxicology, human translation is not guaranteed. However, because nicotine is a known neurodevelopmental toxicant with established mechanisms, these findings are treated as relevant to human pregnancy — consistent with the precautionary principle applied by ACOG and the CDC.
Lung Development: Oxidative Stress and Inflammation
A 2025 study published in PMC examined the impact of e-cigarettes on fetal and neonatal lung development. Key findings:
- Nicotine crosses the placenta and reaches high concentrations in fetal blood and amniotic fluid
- Oxidative stress from e-cigarette vapor impairs fetal lung tissue development through inflammation pathways
- E-liquid components (PG/VG heated) produce compounds (formaldehyde, acrolein) that can damage developing lung tissue
- Flavoring compounds (diacetyl, cinnamaldehyde) may cause additional developmental toxicity — see our vape juice ingredients guide for the full chemical analysis
- The effect occurs with or without nicotine — even nicotine-free e-cigarette vapor caused vascular dysfunction in fetal development
Nicotine-Free Vaping: Still Not Safe
Critical finding: A 2025 study found that vascular dysfunction was evident with or without nicotine in the e-liquid. This means "nicotine-free" vapes are NOT safe during pregnancy. The heating of propylene glycol and vegetable glycerin alone produces harmful compounds that affect fetal development.
Many pregnant women who vape believe that switching to nicotine-free e-liquid eliminates the risk. The evidence says otherwise:
| E-Cigarette Type | Nicotine? | Risk to Fetus | Safe in Pregnancy? |
|---|---|---|---|
| Standard e-liquid (with nicotine) | Yes (3-50 mg/mL) | Nicotine crosses placenta + combustion byproducts + flavorings | NO |
| Nicotine-free e-liquid | No | Vascular dysfunction, oxidative stress, PG/VG thermal compounds | NO |
| Zero vapor (cessation) | None | No exposure — risk drops to baseline | YES |
