Causes and Risk Factors for Premature birth

Ji Keon LOOI
17 August 2007 (First Draft: 14 Aug)
MBBS / MED2042
Week 5: An early arrival
Causes and Risk Factors for Premature birth

What is preterm birth?
•A.k.a. Premature birth
•the birth of a baby before the standard period of pregnancy is completed.
•< 37 weeks since last menstrual period
•Note: standard length of a human gestation is 266 days

•postmature birth is defined as birth more than 42 weeks after the LMP

What causes preterm labour?
•The mechanism that causes normal term labor to begin is not completely understood, so the actual cause of premature labor is also unknown. However, there are some factors that may increase a woman's risk for premature labor.
~ ehealthMD

Factors related to maternal diseases that increases risk of preterm birth
•Idiopathic
•Low socioeconomic status
•high blood pressure
•preeclampsia
•Short interval between pregnancies (< 3 months)
•Age: <18> 40
•weak cervix
–Previous surgery involving the cervix (D+C / Cone Biopsy)
–Cervix dilatation and effacement in the third trimester are at increased risk for preterm birth
•maternal diabetes
•Periodontal disease
–Oral bacteria, especially Fusobacterium nucleatum and Capnocytophaga species, have been associated with upper genital tract infection in pregnant women
•Exposure to diethylstilbestrol (DES)

Factors related to pregnancy history that increases risks of preterm birth
•prior preterm delivery
•prior induced abortion
•antepartum hemorrhage / vaginal bleeding during labor
•prior miscarriage

Others
•Multiple pregnancy
•Sexually transmitted diseases
•Urinary tract infections ( risk of preeclampsia)
•Tobacco and alcohol use


The symptoms of an imminent premature birth
•Four or more uterine contractions in one hour, before 37 weeks' gestation.
•A watery discharge from the vagina which may indicate premature rupture of the membranes surrounding the baby.
•Pressure in the pelvis or the sensation that the baby has "dropped".
•Menstrual cramps or abdominal pain.
•Pain or rhythmic tightening in lower abdomen or back.
•Vaginal spotting or bleeding.

Nice to know
•While it is normally desirable for a pregnancy to reach its full term, there are circumstances in which obstetricians must induce preterm delivery for the safety of the mother, the child, or both.

Induction of premature labor is necessary under:
•Severe hypertension or eclampsia
•a seizure or coma in a woman with pre-eclampsia
•Preterm premature rupture of the membranes (PPROM).
–ruptured amniotic sac prior to the 37th week of pregnancy
•Fetal stress

Have a nice weekend!!!