Her injuries were inflicted primarily as a result of the force of the rocket's impact.
The Mujahideen Brigades, a military wing of Fatah, claimed responsibility for the attack.
The rocket stuck a house that did not have a safe room. It crashed through the roof and caused extensive damage to the house.
The mother of the family was thrown back by the force of the blast and hurled against the wall.
Magen David Adom paramedics said that the woman did not suffer any internal injuries and that she was evacuated to Barzilai hospital while still conscious.
David Abergil, the woman's brother, told Ynet: "When the Color Red alert system was activated, they were at home, the husband, wife and children. Like many houses in Sderot that are not protected (against rocket attacks), you just have to wait and pray for a miracle. They tried to hide and then the Qassam just penetrated their house and she was injured.
The scene at the house in Sderot (Photo: Zeev Trachtman)
"The rocket caused very serious damage to the house. This is not the first time that rockets land in their area. Their daughter still suffers from trauma from one of the rockets that landed previously and she is treated here in Sderot.
"We don't know what the future holds, no one knows when it will end. We're all waiting for the army to enter Gaza and end this."
Next to the house that was hit, many Sderot residents gathered and expressed their frustration with the government's incapacity to end the rocket fire.
"We are angry and there isn't one person who is willing to come and speak with us. Now, Mayor Eli Moyal has resigned and I would expect that a prime minister would formally request that he return to his post," Batya Katar, the head of the local parents committee, said.
As a result of the rocket attack, there have been some problems with the electricity in some of the buildings in the area.
Two Qassam rockets were fired from the northern Gaza Strip into Sderot Thursday morning. One of the rockets landed in an open field on the outskirts of the city.
No injuries or damage were reported.
Heavy barrage Wednesday
On Wednesday, more than 20 of the makeshift projectiles were launched in the direction of Sderot. One woman was lightly injured from shrapnel.
Following the unusually heavy barrage from Gaza, Sderot Mayor Eli Moyal announced his resignation.
A spokesman for the Popular Resistance Committees said that Moyal's resignation was a "great victory for the Palestinian resistance. This is a political and moral victory that adds itself to the humiliation we are administering to the Zionist army in the field."
In reference to the unceasing rocket fire from northern Gaza, Chief of Staff, Lt. Gen. Gabi Ashkenazi, said that "it is impossible to defeat a terrorist organization without, at the end of the day, controlling territory."
According to Ashkenazi, "the reality in Gaza cannot continue the length of time. There is indeed a cumulative value to all of the (military) activities that we are carrying out, but we are not succeeding in bringing (the rocket launchings) to zero.
"It is possible that we will get to a point where we will need to carry out the big act (a reference to a wide-scale military incursion in the Gaza Strip)."