Department of Epidemiology, School of Public Health, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Department of Nutrition and Food Hygiene, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China.
BMC Med. 2022 Jan 11;20(1):4. doi: 10.1186/s12916-021-02196-x.
The associations of maternal cigarette smoking with congenital anomalies in offspring have been inconsistent. This study aimed to clarify the associations of the timing and intensity of maternal cigarette smoking with 12 subtypes of birth congenital anomalies based on a nationwide large birth cohort in the USA.
We used nationwide birth certificate data from the US National Vital Statistics System during 2016-2019. Women reported the average daily number of cigarettes they consumed 3 months before pregnancy and in each subsequent trimester during pregnancy. Twelve subtypes of congenital anomalies were identified in medical records. Poisson regression analysis was used to estimate the risk ratios (RRs) with 95% confidence intervals (CIs) for 12 subtypes of congenital anomalies associated with the timing (i.e., before pregnancy, and during three different trimesters of pregnancy) and intensity (i.e., number of cigarettes consumed per day) of maternal cigarette smoking.
Among the 12,144,972 women included, 9.3% smoked before pregnancy and 7.0%, 6.0%, and 5.7% in the first, second, and third trimester, respectively. Maternal smoking before or during pregnancy significantly increased the risk of six subtypes of birth congenital anomalies (i.e., congenital diaphragmatic hernia, gastroschisis, limb reduction defect, cleft lip with or without cleft palate, cleft palate alone, and hypospadias), even as low as 1-5 cigarettes per day. The adjusted RRs (95% CIs) for overall birth congenital anomalies (defined as having any one of the congenital malformations above significantly associated with maternal cigarette smoking) among women who smoked 1-5, 6-10, and ≥ 11 cigarettes per day before pregnancy were 1.31 (1.22-1.41), 1.25 (1.17-1.33), and 1.35 (1.28-1.43), respectively. Corresponding values were 1.23 (1.14-1.33), 1.33 (1.24-1.42), 1.33 (1.23-1.43), respectively, for women who smoked cigarettes in the first trimester; 1.32 (1.21-1.44), 1.36 (1.26-1.47), and 1.38 (1.23-1.54), respectively, for women who smoked cigarettes in the second trimester; and 1.33 (1.22-1.44), 1.35 (1.24-1.47), and 1.35 (1.19-1.52), respectively, for women who smoked cigarettes in the third trimester. Compared with women who kept smoking before and throughout pregnancy, women who never smoked had significantly lower risk of congenital anomalies (RR 0.77, 95% CI 0.73-0.81), but women who smoked before pregnancy and quitted during each trimester of pregnancy had no reduced risk (all P > 0.05).
Maternal smoking before or during pregnancy increased the risk of several birth congenital anomalies, even as low as 1-5 cigarettes per day. Maternal smokers who stopped smoking in the subsequent trimesters of pregnancy were still at an increased risk of birth congenital anomalies. Our findings highlighted that smoking cessation interventions should be implemented before pregnancy.
母体吸烟与后代先天畸形的关联一直不一致。本研究旨在基于美国全国范围内的大型出生队列，阐明母体吸烟的时间和强度与 12 种出生先天畸形亚型之间的关联。
我们使用了美国国家生命统计系统在 2016-2019 年期间的全国出生证明数据。女性报告了怀孕前 3 个月和每个后续孕期中平均每天吸烟的数量。在医疗记录中确定了 12 种先天畸形亚型。使用泊松回归分析估计了与先天畸形的时间（即怀孕前和怀孕的三个不同孕期）和强度（即每天吸烟的数量）相关的 12 种先天畸形亚型的风险比（RR）及其 95%置信区间（CI）。
在纳入的 12144972 名女性中，9.3%在怀孕前吸烟，7.0%、6.0%和 5.7%分别在第一、第二和第三孕期吸烟。母体在怀孕前或怀孕期间吸烟显著增加了六种出生先天畸形（即先天性横膈疝、腹裂、肢体减少缺陷、唇裂伴或不伴腭裂、单纯腭裂和尿道下裂）的风险，即使每天只吸 1-5 支烟也是如此。每天吸烟 1-5 支、6-10 支和≥11 支的女性患所有上述先天畸形（定义为患有上述任何一种先天畸形）的风险比（95%CI）分别为 1.31（1.22-1.41）、1.25（1.17-1.33）和 1.35（1.28-1.43）。相应的数值分别为 1.23（1.14-1.33）、1.33（1.24-1.42）、1.33（1.23-1.43），分别为第一孕期吸烟的女性；1.32（1.21-1.44）、1.36（1.26-1.47）和 1.38（1.23-1.54），分别为第二孕期吸烟的女性；以及 1.33（1.22-1.44）、1.35（1.24-1.47）和 1.35（1.19-1.52），分别为第三孕期吸烟的女性。与整个孕期持续吸烟的女性相比，从不吸烟的女性先天畸形的风险显著降低（RR 0.77，95%CI 0.73-0.81），但在整个孕期吸烟且在随后的孕期戒烟的女性风险没有降低（均 P>0.05）。
母体在怀孕前或怀孕期间吸烟增加了几种出生先天畸形的风险，即使每天只吸 1-5 支烟也是如此。在随后的孕期戒烟的吸烟母亲仍然存在先天畸形的风险增加。我们的研究结果强调，应在怀孕前实施戒烟干预措施。
