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Changes in Doppler flow velocity waveforms and fetal size at 20 weeks gestation among cigarette smokers
Author(s) -
Kho EM,
North RA,
Chan E,
Stone PR,
Dekker GA,
McCowan LME
Publication year - 2009
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.2009.02266.x
Subject(s) - medicine , umbilical artery , obstetrics , gestation , pregnancy , fetus , prospective cohort study , uterine artery , population , gynecology , gestational age , confounding , genetics , biology , environmental health
Objectives To compare umbilical and uterine artery Doppler waveforms and fetal size at 20 weeks between smokers and nonsmokers. Design Prospective cohort study. Setting Auckland, New Zealand and Adelaide, Australia. Population Nulliparous participants in the Screening for Pregnancy Endpoints (SCOPE) study. Methods Self‐reported smoking status was determined at 15 ± 1 weeks’ gestation. At the 20 ± 1 week anatomy scan, uterine and umbilical Doppler resistance indices (RI) and fetal measurements were compared between smokers and nonsmokers. Main outcomes measures Umbilical and mean uterine artery Doppler RI values, abnormal umbilical and uterine Doppler (RI > 90th centile) and fetal biometry. Results Among the 2459 women, 248 (10%) were smokers. Smokers had higher umbilical RI [0.75 (SD 0.06) versus 0.73 (0.06), P < 0.0001] and mean uterine RI [0.59 (0.09) versus 0.56 (0.10), P < 0.0001]. They were twice as likely to have an abnormal umbilical Doppler at 20 weeks compared with nonsmokers [ n = 35 (14.6%) versus n = 156 (7.2%), OR 2.21, 95% CI 1.49–3.27]. This effect remained significant after adjusting for age, ethnicity, marital status, employment and BMI (adjusted OR 1.62, 95% CI 1.03–2.54). Smokers were more likely to have an abnormal mean uterine RI [ n = 33 (13.7%) versus n = 198 (9.2%), OR 1.57, 95% CI 1.06–2.33], but this association was not significant after adjusting for confounders. Fetuses of women who smoked had a small reduction in femur length and estimated weight compared with nonsmokers. Conclusions At 20 weeks’ gestation, women who smoke have higher umbilical artery RI, a surrogate measure for an abnormal placental villous vascular tree. This may contribute to later fetal growth restriction among smokers. Further research is needed to explore the clinical significance of these findings.