A Cochrane review [Abstract] 1 included 11 studies with a total of 2 412 subjects. Smoking cessation rates in later pregnancy were higher with NRT as compared to control (RR 1.37, 95% CI 1.08 to 1.74; 9 studies, n=2336; I² = 34%). Subgroup analysis of placebo-RCTs provided a lower RR in favour of NRT (RR 1.21, 95% CI 0.95 to 1.55; 6 studies, n=2063, I² = 0%). There were no statistically significant differences in rates of miscarriage, stillbirth, premature birth, birthweight, low birthweight, admissions to neonatal intensive care or neonatal death between NRT or control groups. There was no difference in smoking abstinence rates observed in later pregnancy in women using bupropion vs placebo (RR 0.74, 95% CI 0.21 to 2.64; 2 studies, n=76, I² = 0%). There were no trials of varenicline.
A cross-sectional analysis 2 included a pregnancy cohort of 220 630 singleton pregnancies ending in live or stillbirth. A total of 805 pregnancies ended in stillbirth (3.6/1000 births). Absolute risks of stillbirth in NRT and smoker groups were both 5/1000 births compared with 3.5/1000 births in the control group. Compared with the control group, the adjusted odds of stillbirth in the NRT group was not statistically significant (OR = 1.35, 95% CI 0.91 to 2.00), although it was similar in magnitude to that in the smokers group (OR = 1.41, 95% CI 1.13 to 1.77).
A database study 3 assessed the relationship between early pregnancy exposure to NRT or smoking with major congenital anomalies (MCA) in offspring. MCA prevalence was 288 per 10 000 live births (5535 children with ≥ 1 MCA). Compared with the control group, adjusted ORs for MCAs in the NRT group and smokers were 1.12 (99% CI 0.84 to 1.48) and 1.05 (99% CI 0.89 to 1.23), respectively.
Date of latest search: 2020-04-09
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