Okay, let's tackle this question about placenta previa. The question is asking which statement is not true. The options are a to e, and the correct answer is supposed to be one of them.

First, I need to recall what placenta previa is. From what I remember, placenta previa is when the placenta implants over the internal cervical os, leading to painless vaginal bleeding, especially in the third trimester. It's a common cause of antepartum hemorrhage.

Looking at the options:

Option a says postpartum hemorrhage is infrequent. Wait, but I think placenta previa can lead to postpartum hemorrhage because the placenta is implanted in a low position, maybe leading to incomplete separation or retained placenta. So if postpartum hemorrhage is infrequent, that might be the exception here. But I need to verify.

Option b states first trimester bleeding is not uncommon. Placenta previa usually presents in the third trimester, but maybe some cases are diagnosed earlier. However, the classic presentation is after 20 weeks, so maybe first trimester bleeding isn't typical. Hmm, but the question is about what's NOT true. If option b is false, then it's the correct answer. But I'm not sure.

Option c mentions premature labor. Placenta previa can lead to preterm delivery due to bleeding or other complications, so this is true.

Option d says higher incidence in women with lower segment cesarean section. I recall that previous cesarean sections increase the risk of placenta previa because of scarred uterine tissue, so this is true.

Option e: malposition and malpresentation are common. In placenta previa, the placenta covering the cervix can prevent the fetus from engaging, leading to breech or transverse lie, so malpresentation is common. So e is true.

So the incorrect statement would be option a or b. Let me check again. Postpartum hemorrhage in placenta previa: because the placenta is implanted in the lower uterine segment, which has less contractile tissue, so after delivery, the area may not contract well, leading to postpartum hemorrhage. So postpartum hemorrhage is actually more common, making option a incorrect. Therefore, the correct answer is a.

But wait, the options are a) postpartum hemorrhage infrequent, so if it's actually common, then a is false. That makes a the correct answer. Let me confirm. Yes, postpartum hemorrhage is a known complication of placenta previa because the lower segment has weaker muscle, leading to poor contraction and bleeding. So the statement that it's infrequent is incorrect. Therefore, the answer is a.

**Core Concept**
Placenta previa is characterized by abnormal placental implantation over the internal cervical os, leading to painless antepartum bleeding. It increases risks of postpartum hemorrhage, preterm birth, and malpresentation due to altered uterine anatomy and placental positioning.

**Why the Correct Answer is Right**
Postpartum hemorrhage is **common** in placenta previa. The lower uterine segment has weaker myometrial tissue and reduced vascularity, leading to poor uterine contraction after delivery. Additionally,

✓ Correct Answer: C. ab