It's plausible, but unclear. According to official statistics, Iranian women have a significantly lower maternal mortality rate than Ohio blacks. However, who has the higher infant mortality rate is harder to judge, because it has a less clear definition, the stats for the two populations are close, the rates are very similar and year-on-year changes potentially flip the result from one year to the next, and different sources disagree on what the rate is - for both Iran and Ohio - by enough to flip which of them has the higher rate.
The World Bank put the maternal mortality ratio for Iran in 2015 at 25 per 100000 live births. (Source: https://databank.worldbank.org/data/reports.aspx?source=2&series=SH.STA.MMRT.) America's Health Rankings, on the other hand, puts the rate for blacks in Ohio at 46 per 100000 live births in 2018. (Source: https://www.americashealthrankings.org/explore/health-of-women-and-children/measure/maternal_mortality/state/OH.) Thus the comparison to Iran is probably true insofar as it applies to maternal mortality.
The claim about infant mortality, however is harder to be sure of. In part this is because of differences in reporting standards, explored (in the context of US healthcare) in Joseph Ahern's article Do Differences in Reporting of Live Births Affect Comparability of Infant Mortality Rates?. (Spoiler: the answer is "yes".) Per official definition, any death of an infant who is born alive but then dies prior to their first birthday is supposed to count towards infant mortality statistics. In practice, however, the authors note that, for the purposes of statistical reporting, hospitals in some jurisdictions routinely consider premature babies born prior to a certain gestational age not to have been born alive - even if, in reality, they were - despite this practice having no justification in the definitions used by either the (international) WHO or the (American) CDC. For instance, they note that some hospitals in New York City do not count actually-alive births of babies of under 23 weeks' gestational age as live births. The article notes that the average "infant mortality rate" of hospitals in NYC that follow the official definitions strictly is 3.54 per 1000 live births, while those that apply a 23 week cutoff have a rate of 2.68 per 1000 live births. Though not explicitly stated, it seems to be implied that this one-third difference owes entirely to the difference in definitions.
This caveat is worth bearing in mind as we note that:
Depending upon which of these different stats we believe - if any of them - the infant mortality rate for African Americans in Ohio could be higher or lower than the overall rate in Iran. I don't know how to judge which of the stats are true, so I can't tell. Regardless of which is true, it's possible that the nominal "infant mortality rate" is really measuring a different thing in each country due to differences in reporting, potentially rendering the comparison between them meaningless.
Finally, note that America Health Rankings puts the overall infant mortality rate for Ohio at 7 per 1000 live births, suggesting that blacks have an infant mortality rate of only two times that of the general population. On maternal mortality, the stats are 20.3-per-100000 for the whole population vs 46-per-100000 for blacks. So Ryan's suggestion that blacks are 300-400 times more likely to suffer a death in childbirth - even if we charitably assume that he really meant 300%-400% more likely - seems not to be true. The real stat is more like "100% more likely".