Here is the full list of all 46 Conception PLUS: Maidens of the Twelve Stars achievements.
Clear 1 Constellation Labyrinth.
Complete a total of 8 Chain Combos.
Give birth to 12 Star Children.
Visited the Map Point "Day Camp."
Visited the Map Point "Scavenger."
Visited the Map Point "Gift Shop."
Give birth to your first Star Child.
Obtain all achievements.
Clear 2 Constellation Labyrinths.
Clear 3 Constellation Labyrinths.
Clear 4 Constellation Labyrinths.
Clear 6 Constellation Labyrinths.
Clear 12 Constellation Labyrinths.
Insta-kill 100 Impurities.
Complete a total of 100 Chain Combos.
MECUNITE a total of 10 times.
Use all Team Colors.
Give birth to the special class "Ninja."
Give birth to the special class "Sage."
Give birth to the special class "Dungeon Master."
Give birth to the special class "Bondsman."
Give birth to a Star Child of each class.
Give birth to 200 Star Children.
Have 25 Star Children go independent.
Have 100 Star Children go independent.
Perform the Tri-Mating ritual.
Complete all quests.
Obtain all weapons.
Obtain all armor.
Obtain all accessories.
Complete main scenario.
Complete Arie's ending.
Complete Tarua's ending.
Complete Lillith's ending.
Complete Ruka's ending.
Complete Femiruna's ending.
Complete Mahiru's ending.
Complete Mirei's ending.
Complete Reone's ending.
Complete Sue's ending.
Complete Farun's ending.
Complete Collette's ending.
Complete Yuzuha's ending.
Complete Alfie's ending.
Complete Normal ending.
Complete Harem ending.