Boissière-O'Neill Thomas, Schnitzer Mireille E, Lewin Antoine, Bilodeau-Bertrand Marianne, Ayoub Aimina, Auger Nathalie
Department of Pharmacy, University of Aix-Marseille, Marseille, France; Institut national de santé publique du Québec, Montreal, QC, Canada.
Faculty of Pharmacy, University of Montreal, Montreal, QC, Canada.
Ann Epidemiol. 2021 Jul;59:10-15. doi: 10.1016/j.annepidem.2021.03.007. Epub 2021 Mar 30.
We assessed whether the protective association between hyperemesis gravidarum and birth defects could be due to selection bias from exclusion of pregnancy terminations.
We designed a cohort study of 2,115,581 live births in Canada, 1990-2016. The main exposure measure was hyperemesis gravidarum. The main outcome measure included any birth defect at delivery. We estimated risk ratios (RR) and 95% confidence intervals (CI) for the association of hyperemesis gravidarum with birth defects in log-binomial regression models, and assessed the extent of selection bias through correction factors.
Hyperemesis gravidarum was associated with 0.88 times the risk of birth defects in models not corrected for bias (95% CI 0.82-0.94). Correction for selection bias suggested that if screening for birth defects was associated with 1.33 times the chance of detecting birth defects and having a pregnancy termination, there would be no association with hyperemesis gravidarum. If ultrasound was associated with 2.00 times the chance of detecting birth defects and 1.50 times the risk of pregnancy termination, hyperemesis gravidarum would be associated with 1.27 times the risk of birth defects (95% CI 1.18-1.35).
The protective association between hyperemesis gravidarum and birth defects in previous studies may be due to selection bias.
我们评估了妊娠剧吐与出生缺陷之间的保护性关联是否可能是由于排除了妊娠终止导致的选择偏倚。
我们设计了一项队列研究，纳入了1990 - 2016年加拿大2,115,581例活产。主要暴露指标是妊娠剧吐。主要结局指标包括分娩时的任何出生缺陷。我们在对数二项回归模型中估计了妊娠剧吐与出生缺陷关联的风险比（RR）和95%置信区间（CI），并通过校正因子评估选择偏倚的程度。
在未校正偏倚的模型中，妊娠剧吐与出生缺陷风险的关联为0.88倍（95% CI 0.82 - 0.94）。选择偏倚校正表明，如果出生缺陷筛查与检测到出生缺陷并进行妊娠终止的可能性为1.33倍相关，则与妊娠剧吐无关联。如果超声检查与检测到出生缺陷的可能性为2.00倍且妊娠终止风险为1.50倍相关，妊娠剧吐与出生缺陷风险的关联将为1.27倍（95% CI 1.18 - 1.35）。
先前研究中妊娠剧吐与出生缺陷之间的保护性关联可能是由于选择偏倚。
