Some women have a weak or short cervix[1] (the strongest predictor of premature birth)[51][52][53] Women with vaginal bleeding during pregnancy are at higher risk for preterm birth. While bleeding in the third trimester may be a sign of placenta previa or placental abruption – conditions that occur frequently preterm – even earlier bleeding that is not caused by these conditions is linked to a higher preterm birth rate.[54] Women with abnormal amounts of amniotic fluid, whether too much (polyhydramnios) or too little (oligohydramnios), are also at risk.[6] The mental status of the women is of significance.