A variety of risk factors have been implicated in identifying pregnant women who are at risk for preterm delivery. A woman with one or more risk factors may benefit from more aggressive monitoring and early interventions.


Preterm delivery: delivery prior to end of the 37th week of gestation from last menstrual period


Risk factors include:

(1) age - younger (< 18) or older (> 40)

(2) alcohol abuse

(3) anemia, including hemoglobinopathy

(4) Black race

(5) bleeding in first or second trimester

(6) cervical insufficiency

(7) congenital anomalies in fetus

(8) diabetes mellitus

(9) drug abuse

(10) high altitude

(11) history of hypertension

(12) history of previous preterm delivery

(13) history of spontaneous abortion

(14) hyperemesis

(15) hypertension during pregnancy, including pre-eclampsia

(16) hypotension during pregnancy

(17) inadequate antenatal care

(18) infection, including bacterial vaginosis, bacteriuria, rubella, CMV, STD

(19) isoimmunization

(20) low education

(21) low socioeconomic status

(22) low weight increase during pregnancy

(23) multiple gestation (twins, triplets, etc)

(24) oligohydramnios, polyhydramnios

(25) placenta previa or abruptio placentae

(26) poor nutrition

(27) primipara or multipara with more than 4 deliveries

(28) short interval between pregnancies (less than 1 year)

(29) smoking

(30) spontaneous premature rupture of membranes

(31) toxins in environment

(32) underweight or overweight

(33) unmarried

(34) uterine anomaly

(35) uterine contractions


Some risk factors carry more significance than others. For example, the presence of a previous preterm delivery or spontaneous abortion is associated with a significant risk for recurrence.


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