In nearly all states, pregnancy-related Medicaid provides the same (or similar) benefits as Medicaid for other adults and so is considered minimum essential coverage (MEC). The general rule requires that people eligible for other MEC are not eligible for advance premium tax credits (APTC). However, a special rule allows women who are already receiving APTC and who become pregnant and eligible for pregnancy-related Medicaid to choose whether to stay in their Marketplace plan with APTC or enroll in the pregnancy-related Medicaid. For example, women might choose pregnancy-related Medicaid because it does not charge monthly premiums or cost sharing for covered services.
If you decide to enroll in the pregnancy-related Medicaid, in most states, you will no longer be eligible for APTC while you are enrolled in Medicaid.

In all states, when your pregnancy and pregnancy-related Medicaid ends, you will be eligible for a special enrollment period (SEP) and can sign up for Marketplace coverage and APTC at that time. But if you prefer to stay in your Marketplace plan you can continue receiving APTC and won’t be required to pay it back later just because you were eligible for pregnancy-related Medicaid.