If you answer questions truthfully and check the "pregnant" checkbox on healthcare.gov (previewing the plans, not an actual application), does it tell you something different than if you don't?
Yes. Using FL as example, family of three, with $25,000 income.
First scenario, nobody pregnant:
Person #1 (age 33) may be eligible for a premium tax credit that lowers the monthly costs of health insurance.
Person #2 (age 34) may be eligible for a premium tax credit that lowers the monthly costs of health insurance.
Person #3 (age 2) may be eligible for coverage through Medicaid or the Children's Health Insurance Program (CHIP).
Based on the information you provided, it looks like your household qualifies for a premium tax credit of $556 per month
Second scenario, Person #2 pregnant, all esle same:
Person #1 (age 33) may be eligible for a premium tax credit that lowers the monthly costs of health insurance.
Person #2 (age 34) may be eligible for coverage through Medicaid or the Children's Health Insurance Program (CHIP).
Person #3 (age 2) may be eligible for coverage through Medicaid or the Children's Health Insurance Program (CHIP).
Based on the information you provided, it looks like your household qualifies for a premium tax credit of $255 per month
In scenario 2, it proceeds to only show health plans with coverage for Person #1.