Peer-reviewed article
Antagonistic effects of smoking and maternal glycemia on fetal growth: a retrospective study among 13,958 pregnant French women.
Emmanuel Cosson, Lionel Carbillon, Sopio Tatulashvili, Hélène Bihan, Eric Vicaut et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study analyzed data from nearly 14,000 pregnant French women to understand how smoking and high blood sugar during pregnancy affect fetal growth. The researchers found that high blood sugar increases the risk of large babies, while smoking decreases it—these effects partially cancel each other out. Women with high blood sugar who also smoked had increased risks of complications like high blood pressure and needed more intensive care for their babies, even though their babies were not larger.
Key points
- High blood sugar in pregnancy (H1inP) increased the risk of large-for-gestational-age babies (odds ratio 1.50)
- Maternal smoking decreased the risk of large-for-gestational-age babies (odds ratio 0.35)
- Smoking and high blood sugar showed antagonistic effects on fetal growth, with smoking masking the hyperglycemia effect
- Women with both high blood sugar and smoking had higher rates of hypertensive disorders and neonatal intensive care unit admissions
- Smoking was associated with more small-for-gestational-age babies, even when mothers had higher gestational weight gain
Limitations
This is a retrospective observational study, so it cannot establish causation or control for all unmeasured confounding factors. The group of women with both smoking and high blood sugar was small (n=115), limiting statistical power for that comparison.
Abstract
INTRODUCTION: Smoking and hyperglycemia first diagnosed during pregnancy (H1inP) have opposing effects on fetal growth. The aim of this study was to explore adverse pregnancy outcomes, particularly fetal growth, according to the smoking and H1inP status. METHODS: We included 13,958 women from a large French dataset (2012-2018). Using multivariable regression analyses, we retrospectively evaluated the risk of large-for-gestational-age (LGA) babies and other adverse outcomes according to the H1inP and smoking status in four groups: no H1inP/non-smoker (group A: n = 10,454, 88.2%), no H1inP/smoker (group B: n = 819, 5.9%), H1inP/non-smoker (group C: n = 2,570, 18.4%), and H1inP/smoker (group D: n = 115, 0.8%). RESULTS: The rates of LGA were 8.9%, 4.0%, 14.6%, and 8.7% in groups A, B, C, and D, respectively (global ANOVA p < 0.0001, factor H1inP p = 0.0003, factor smoking p = 0.0002, and interaction p = 0.48). After adjustment for potential confounders including age, body mass index, employment, ethnicity, parity, hypertension before pregnancy, gestational weight gain, and alcohol and drug consumption, H1inP was associated with a higher risk [odds ratio (OR) = 1.50, 95% confidence interval (95%CI) = 1.30-1.74] and smoking with a lower risk (OR = 0.35, 95%CI = 0.25-0.50) of LGA. In addition, H1inP was associated with a lower total gestational weight gain and a lower rate of small-for-gestational-age (SGA) babies, but higher rates of hypertensive disorders and more frequent caesarean sections and admissions in the neonatal intensive care unit. Smoking was associated with higher rates of SGA, including severe SGA (<3rd centile), and this despite a higher total gestational weight gain. Smoking increased the risk of hypertensive disorders only in women with H1inP. DISCUSSION: Smoking among women with H1inP could mask the risk of maternal hyperglycemia for LGA babies. This could provide a false sense of security for women with H1inP who smoke, particularly when assessing for LGA alone, but these women still face other risks to their health, such as hypertensive disorders and the health of the fetus.