PreTerm Birth (PTB)

PreTerm Birth (PTB) is caused by a weak cervix (or incompetent cervix) that creates changes to the internal cervical os by dilating or increasing the "funneling" angle and reducing cervical length (CL). As a result, the cervix may open early thus inducing a preterm delivery or miscarriage (spontaneous abortion). Essentially, more than 70% of premature babies are born between 34 and 36 wks (late preterm); 12% are born between 32 and 33 wks; and 10% are born between 28 and 31 wks.

In order to prevent this early labor from arising, a procedure known as a cervical "cerclage" is done to suture or stitch shut the cervix to prevent further dilation. The procedure can be done at about 12 to 14weeks before the cervix thins out, or as a emergency measure after the cervix has thinned (rarely done after 24 wks). However, the risks of cervical cerclage are rare but may include: infection, pPROM, cervical stenosis (d/t permanent narrowing or closure of the cervix), damage to the cervix during surgery, and excessive blood loss.

All premature babies are at risk for health problems, but the earlier a baby is born, the greater the risk for serious complications. For example, if a premature baby gets delivered before 32wks GA, the baby will appear small with organs less developed. Or if the baby is born at 36 wks GA but fetal weight is below the 10th percentile (weighing less than 2500 grams), then suspect Intrauterine Growth Restriction (IUGR) or "Small-for-Gestational Age"(SGA) fetus.

IUGR is a smaller than normal fetus caused by wrong LMP (blame mom),diminished amniotic fluid, pPROM, abnormal placenta, or fetal renal anomaly. The fetus is small because of insufficient nutrition due to alcohol/drug abuse, any chronic conditions (HRT Dz), does not eat well, or has had previous pregnancies in which there was poor fetal growth. IUGR has three types: asymmetric (seen late in 3rd Trimester), symmetric (seen early in pregnancy), and femur-sparing pattern.

In asymmetric IUGR, fetal trunk is small. In symmetric IUGR, entire fetus is smaller than normal, which also includes reduced sizes of internal organs (Nuchal thickening can also be assessed). In femur-sparing pattern IUGR, BPD is normal but AC and FL are low thus the brain and head is spared, but body or abdomen is considered small (usually not seen in late 3rd trimester).