The No. 1 U.S. automaker's shares were down 2.7 percent in morning trading.
"We remain concerned with the U.S. auto cycle, both from a pricing and volume perspective," Buckingham Research analyst Joseph Amaturo wrote in a client note. "Moreover, specific to GM, we are concerned about recently monthly pick-up truck and market share stats."
GM's sales in China also dropped almost 20 percent and profit there declined 37 percent. Auto sales in China industrywide fell 2.8 percent last year and were down again in the first quarter.
GM Chief Financial Officer Dhivya Suryadevara told reporters that the Chinese market remains "volatile."
"From an economic standpoint, there are green shoots," she said. "But we have yet to see that translate to vehicle demand."
GM will launch 20 new models in China in 2019, most of them in the second half of the year.
In the United States, the automaker had around four months supply of its Chevrolet Silverado pickup truck on the ground as of the beginning of April, a high level in an auto market that overall is expected to decline in 2019.
CFO Suryadevara said that the company's inventory would be brought down over the course of the year without use of heavy consumer discounts.
She said that tariffs and higher commodity prices would cost GM around $1 billion in 2019.
As recently as late last year, GM executives insisted the automaker's Cruise self-driving unit would launch a commercial ride-hailing service by the end of 2019.
However, when asked several times on Tuesday when that service would launch, neither CFO Suryadevara nor Chief Executive Mary Barra would provide a date, repeatedly responding that GM's efforts would be "gated by safety."
GM said it is "bullish" on pickup truck sales for the rest of 2019 as more versions of its new Silverado hit dealer showrooms and its heavy-duty trucks launch in the second half of the year.
Last week, rival Ford Motor Co reported a higher-than-expected first-quarter profit on strong pickup truck sales in its core U.S. market and said it was confident its 2019 results would be better than those of last year.
Ford said last week it will invest $500 million in U.S. electric vehicle startup Rivian Automotive LLC, joining Amazon.com Inc in backing the potential rival to Silicon Valley's Tesla Inc. According to sources, GM had previously been in talks with Rivian about a possible investment.
GM CEO Barra told analysts on Tuesday the automaker will produce a full range of electric vehicles, including an all-electric pickup truck, but she did not provide details.
General Motors has preferred shares in Peugeot from when it sold its German Opel unit to the Paris-based automaker in 2017. Lyft completed an initial public offering at the end of the first quarter and the value of GM's stake rose $300 million. The increased value of those stakes added 31 cents per share to GM's first-quarter profit.
GM reported a first-quarter net profit of $2.2 billion, or $1.48 per share, up from $1.05 billion, or 72 cents per share, a year earlier.
Excluding one-items, the company earned $1.41 per share.
Analysts on average expected $1.11.
The company's revenue for the quarter fell to $34.9 billion from $36.1 billion a year earlier.
GM reiterated its full-year 2019 profit outlook for earnings per share of between $6.50 and $7.