As Samantha Carter (Amanda Tapping) takes over command of the Stargate Atlantis expedition, she will have to do more than just worry about the constant expressions of lust from Rodney McKay (David Hewlett).

The fourth season of Atlantis will feature a new alien race with technology far beyond that of the expedition, as well as a storyline centered around the real-life pregnancy of Rachel Luttrell (“Teyla Emmagan”).

“We had a story in development where [Teyla] would be out in the woods with Jewel [Staite], and it was a fairly violent episode,” said Paul Mullie, executive producer of Atlantis, during Tuesday’s SCI FI Channel digital media tour in Vancouver, B.C. “We were writing the story when [Luttrell] came in and told us she was pregnant. We were too far down the road to change it, so we decided that, ‘Oh well, she doesn’t know she’s pregnant in this story.’ It was the story which in the end she finds out.”

Producers decided to write Luttrell’s pregnancy into the show, although they would not give details on exactly how the pregnancy would be incorporated. Luttrell, who was showing physical signs of her pregnancy at the press event, said jokingly that her pregnancy was a way to make sure that the producers further developed her character in the fourth season.

“This was to ensure more of a character arc,” Luttrell said. Mullie, however, added that they had wanted to incorporate a strong story arc for Teyla in the fourth season, and her pregnancy made it that much easier to find a way to do it.

Outside of making babies, the Atlantis expedition is going to make contact with its first race that is actually far more technologically advanced than just about every other culture they have faced. Because cultures in the galaxy tend to not advance very far society-wise because of cullings by the Wraith, cultures that are more advanced than those manning Atlantis have been few and far between.

However, the Travelers, as they are called, are expected to make an appearance early in the fourth season (“Travelers”).

“One of the things that Atlantis kind of lacked that [Stargate SG-1] had were technologically advanced races,” said executive producer Joseph Mallozzi. “We created this race called the Travelers. They are nomads, traveling on ships and establishing a civilization. They are very rustic, and have a very cool look.”

The Travellers are expected to show up again sometime after the fourth episode during the upcoming season, Mallozzi said.