Labor before 36 Weeks
Certain pregnancies have a greater chance of early labor and delivery: twins, two or more previous leep or cone procedures to the cervix, and a history of delivery between 20 and 34 weeks. These pregnancies can be called high surveillance, rather than high risk. Early delivery is not easily prevented, but there are a number of things we do to help a baby get the most amount of time and the most beneficial time inside the uterus.
Testing and treatment for early labor and advanced dilation of the cervix depend upon the frequency of contractions AND how much the cervix is dilated. And much of what we do is based on gestational age.
Before 13 weeks
Cervical examination – “Fingers in vagina” exam is more useful than ultrasound at this time in pregnancy.
13 weeks to 20 weeks
If cervical cerclage is needed, this is the time to do it. Cervical cerclage is a “stitch” (or two) placed in the cervix, intended to hold the cervix closed during pregnancy. The stitch is removed when labor starts OR around 36 weeks, whichever comes first. Cervical cerclage can be recommended based on what happened in a previous pregnancy. An ultrasound measurement of the cervix, less than 2 cm before 20 weeks is a reason to consider cervical cerclage.
16 to 36 weeks
17 OH Progesterone Caproate is a a weekly shot, administered between 16 weeks and 36 weeks, to women who had a preterm delivery. Preterm is defined as delivery before 36 weeks and 6 days.
20 weeks to 24 weeks
This is the transition period between miscarriage and early labor. At 24 weeks a baby can survive outside the uterus, but survival may be only 50%. By 29 weeks survival is approximately 90%. “Fingers in the vagina” cervix checks are used to assess cervical change. At this gestational age, ultrasound is no longer very useful in the management of early labor. Cervix checks at 20, 22, and 24 weeks can be used to plan the next phase of surveillance.
Contractions After 24 weeks
Patients who are having regular contractions, more than 5 per hour, or an increase in vaginal discharge or vaginal bleeding, should be seen and evaluated for premature labor. Treatment for contractions may include intravenous magnesium sulfate OR oral nifedipine. Bedrest is routinely used in the treatment of early labor, even though it has not been proven to prevent early delivery.
24 weeks to 34 weeks
If contractions are rare or absent then office visits are scheduled weekly or every other week, to detect if the cervix is dilating silently. If the cervix begins to dilate (with or without contractions) we consider steroid treatment. The absence of a cervical-vaginal protein called fetal fibronectin suggests that labor is Not coming within the next week. If needed, we can test for fetal fibronectin.
- The National Institutes of Health recommends steroid shots for those mothers who are in early labor. These are not “I want big muscle” steroids. These are “stress” steroids, like cortisone. Steroids are not just for the lungs; they seem to help many organs. Steroids help babies born before 34 weeks, or before 32 weeks if the water bag is already broken. The full NIH statement is on their web site.
34 to 35 weeks
After 34 weeks labor is not stopped in pregnancies that have already received the steroids shots. After 35 weeks there is no proven benefit to stopping labor. Babies are medically Better Off delivered, if labor starts after 35 weeks.