Antenatal testing in uncomplicated pregnancies: should testing be initiated after 40 or 41 weeks?

This study aims to compare outcomes of antenatal testing in women who received testing between 40 weeks and 40+6 weeks versus those who received testing at ≥41 weeks.

This retrospective study included women without maternal comorbidities, who were referred for outpatient antenatal testing for gestational age ≥40 weeks. We compared women who received antenatal testing between 40 and 40+6 weeks (Group 1), to those who were only tested at ≥41 weeks (Group 2).

A total of 827 Group 1 and 244 Group 2 pregnancies were evaluated. One-hundred and eighty-nine (18%) were sent to labor and delivery (L&D) for further evaluation. There were no significant differences between groups in terms of being sent or admitted to labor and delivery, the reason for which women were sent, induction of labor, mode of delivery, neonatal length of stay, or admission to intensive care.

Pregnancies tested at 40 weeks were identified as abnormal and sent to L&D at the same rate as those tested at 41 weeks. Therefore, it may be reasonable to initiate fetal surveillance at the estimated date of delivery.