Pre-eclampsia, birth weight, and autism spectrum disorders.

R et al. pulled every Medicaid birth record from 1994-2003 in South Carolina. They kept kids who later got an ASD diagnosis and matched each one to four kids without ASD.

They checked two things: did mom have pre-eclampsia or eclampsia, and what did the baby weigh at birth? Then they ran numbers to see if either event raised the odds of later autism.

Pre-eclampsia lifted ASD odds by a large share. Every extra kilogram of birth weight cut the odds a large share. Both results stayed strong even after the team held constant mom’s age, race, and Medicaid status.

Low birth weight and high blood-pressure pregnancy each mattered on their own. The pair did not have to show up together to drive risk up.

Li et al. (2016) pooled five studies and found mom’s obesity also raises ASD odds. Pre-eclampsia, obesity, and low birth weight all point to the same idea: a stressed pregnancy environment can tilt neurodevelopment.

Peters et al. (2013) went deeper. They showed smoking in pregnancy hikes risk only for the broader ASD label (PDD-NOS) and lowers IQ in that group. R et al. looked at all ASD as one block, so the smoking paper extends their work by splitting the spectrum.

Che et al. (2025) flipped the lens: moms who ate a Mediterranean-style diet had kids with better social scores. Together these papers trace a line from bad (pre-eclampsia) to good (healthy diet) prenatal inputs.

You can’t change birth history, but you can use it. When an assessment shows low birth weight or mom had pre-eclampsia, flag the child for closer developmental watch. Share the numbers with pediatricians and families so they know early signs matter. The a large share odds jump is big enough to justify extra screening at 18- and 24-month visits.