Walking on a freshly sprayed lawn while pregnant

What does the evidence say about lawn fertilizer and weed killer during pregnancy?

1. Pesticides, including lawn weed-and-feed products, can enter the body by being breathed in, absorbed through the skin, or eaten if they land on food, and wind can carry spray beyond the area it was applied to. 1
2. MotherToBaby considers it unlikely that having a home or yard sprayed by a professional pesticide company results in a high enough exposure to raise pregnancy risk. 1
3. In one study, household members who didn't personally apply a 2,4-D lawn herbicide, a common weed-and-feed ingredient, had urine levels below the detection limit, with the researchers concluding that mixing, loading, and applying the product drives exposure far more than simply living near where it was used. 2
4. 2,4-D has an estimated half-life of about 59 days in urban soil and has turned up in pet urine after a household lawn application, both reasons to keep kids and pets off freshly sprayed grass for a while rather than assume it's gone once it dries. 3
5. One study measuring 2,4-D in umbilical cord blood found the herbicide in about 27 percent of samples, and infants with the highest levels showed slightly slower auditory nerve responses at 6 weeks old, a difference that had faded by later testing. 4

Is lawn fertilizer and weed killer safe in each trimester?

• First trimester. This is when a baby's organs are forming fastest, so it's a reasonable trimester to let someone else schedule and handle the lawn service and to stay off the grass a little longer than the label suggests.
• Second trimester. The research reassurance here is specifically about not personally mixing or applying the product; simply living in a house with a serviced lawn showed chemical levels below detection in the one study that looked at it.
• Third trimester. 2,4-D, a common ingredient in weed-and-feed mixes, has an estimated soil half-life of about two months, so grass that looks and feels dry can still carry residue well after a single application.