As a solution to methodologic challenges inherent to estimating causal effects of exposures in early pregnancy, we suggest emulating a target trial using a treatment decision design, wherein time zero is centered around clinical landmarks where treatment decisions may occur, such as the date of preconception counseling or prenatal care initiation. These ideas are illustrated via protocols for two target trials in large administrative databases, antidepressant use for pre-existing depressive disorder and antihypertensive medication use for mild-to-moderate chronic hypertension. Careful consideration of these issues is critical to the identification of the causal effects of early-pregnancy pharmacotherapies on pregnancy outcomes.

翻译：针对孕期早期暴露因素因果效应估计中固有的方法学挑战，我们建议采用治疗决策设计模拟目标试验，将时间零点设定在可能发生治疗决策的临床里程碑节点（如孕前咨询日期或产前保健启动日期）。通过大型行政数据库中的两项目标试验方案（抗抑郁药用于孕前抑郁障碍、抗高血压药用于轻中度慢性高血压）阐明上述思路。审慎考虑这些关键问题对于识别孕早期药物治疗对妊娠结局的因果效应至关重要。