Is the scopolamine patch safe during pregnancy?

What does the evidence say about scopolamine patch during pregnancy?

1. Transderm Scop is a prescription patch that delivers 1 mg of scopolamine over 3 days, labeled for adults for motion sickness and post-operative nausea and vomiting, applied at least 4 hours before the effect is needed. 1
2. The label's pregnancy section reports that eclamptic seizures have been reported in pregnant patients with severe preeclampsia soon after scopolamine injection, and that embryotoxicity was seen in rabbits at intravenous doses producing plasma levels roughly 100 times those achieved with a transdermal system. 1
3. By contrast, doxylamine succinate with pyridoxine hydrochloride has been studied in hundreds of thousands of pregnancies without an increased chance of birth defects, which is the evidence base the patch does not have for pregnancy nausea. 2
4. Diphenhydramine, an over-the-counter antihistamine, is separately approved for motion sickness at 25 to 50 mg starting 30 minutes before the event, which gives providers a more familiar comparator to weigh. 3
5. Non-drug PC6 wrist stimulation reduced nausea against sham (RR 0.68 across 40 trials and 4,742 participants) with side effects limited to minor, transient, self-limiting skin irritation, blistering, redness, and pain. 4

Is scopolamine patch safe in each trimester?

• First trimester. The patch is not one of the studied first-trimester nausea options. The doxylamine plus pyridoxine pairing has hundreds of thousands of studied pregnancies behind it, which is a different order of evidence entirely.
• Second trimester. If the question is a flight or a cruise rather than morning sickness, the same gap applies. The label's own human pregnancy data amounts to case reports, and the estimated background risk of major birth defects for this population is described as unknown.
• Third trimester. Post-operative use is the one setting where a provider might raise it, since the label describes applying it the evening before scheduled surgery and removing it 24 hours after. That decision belongs to the surgical and obstetric teams together.

What the Transderm Scop label says