TL;DR: The claim is true within reasonable rounding margin.
Looking at a statistic of women in national parliaments, things don't appear to be so bad. The US is 69th. However, if you count ties as multiple ranks, the US comes in at 89th (thanks @Flimzy and @Oddthinking) - reasonably close to 90th. Furthermore, it is indeed behind Cuba (5th), China (51th), Iraq (35th) and Afghanistan (30th). The US is also behind Germany (19th), Switzerland (26th), France (60th), and the UK (48th).
Note that the statistics rank the countries according to the lower house (or single, if there are not two houses). If both houses were counted together, where applicable, the US would actually lose 8 ranks: Barbados, Antigua and Barbuda, St. Lucia, Bahamas, Grenada, Swaziland, Ireland, Zimbabwe all would get more than 17% representation.
The source linked above is what e.g. the parliament of Canada (39th) links to in discussing how the situation in Canada can be improved. The Canadian report also mentions how election procedures can help or hurt women (and other underrepresented groups):
Canada’s electoral system is a “single-member plurality” or “first-past-the-post” system. In every federal electoral district, the candidate with the most votes wins a seat in the House of Commons and represents that riding as its Member of Parliament. It has been argued that this system tends to discourage the election of women and other under-represented groups.