Title I: Short Title - Medicaid Infant Mortality Amendments of 1990 - Title II: Infant Mortality Provisions - Amends title XIX (Medicaid) of the Social Security Act to phase-in mandatory State coverage of pregnant women and infants whose family income is below 185 percent of the Federal poverty level. Deducts child and medical care costs from the income eligibility test. Directs the Secretary of Health and Human Services to report to the Congress by July 1, 1991, on State error rates in determining the Medicaid eligibility of pregnant women and infants. Suspends error rate penalties attributable to such eligibility determinations made from July 1, 1989, until one year after the Secretary's report.

Requires that States make ambulatory prenatal care available to a pregnant woman during a presumptive eligibility period which ends when she is determined to be ineligible for Medicaid benefits or at the close of the month following the month in which she is determined to be eligible, if she fails to apply for such benefits.

Authorizes States to provide Medicaid coverage of prenatal home visitation services for high-risk pregnant women and/or postpartum home visitation services for high-risk infants.

Excepts Medicaid-eligible pregnant women from required cooperation with States in establishing the paternity of children born out of wedlock.