Ay, normal yan sa 26 weeks, mamsh! Constipation talaga ang common culprit kasi ang progesterone at ang baby na lumalaki ay nagsasagabal sa digestion, kaya maraming pregnant friends ko ang nag-complain nito around that time. Try drinking lots of water, eating more fiber like fruits and veggies, at light walking if kaya mo, kasi tumutulong talaga yan; pero kung ang sakit persistent or nag-worry ka na, better check with your OB just to be safe kaya sure tayo na okay lang baby at ikaw din.