Time after Time: Recurrent Preterm Birth

Trying to figure out when your little one will make his/her first appearance is a game many of us have played. And while family and even office pools are often centered on birth stats (I’ll take a girl on Tuesday, May 18, weighing 7 lbs., 2 oz.), when the grand finale will actually take place is really nothing more than a guessing game, minus those who have scheduled a C-Section or an induction! No matter how much you like fours or sevens, evens or odds, babies come when babies come. Bottom line, don’t take this bet to Vegas. The odds are not likely to be in your favor, and you probably need to save your money. Diapers aren’t cheap! Just like those who go to Vegas and count cards, we OBs have some ways to “cheat” and figure out who is likely to deliver early, sometimes even weeks before their due date. And although we wish it was because we were all-knowing, it’s really because women who have a history of a spontaneous preterm birth (delivery at less than 37 weeks because of preterm labor or preterm rupture of membranes) are significantly more likely, about 1.5–2X, to be exact, to deliver early in their next pregnancy. In fact, one of the strongest risk factors for preterm birth is a prior preterm birth. Add to that the number of times you delivered early (one vs. two vs. three, etc.) and how many weeks you were at delivery (24 vs. 26 vs. 28, etc.), and you have an even better idea about whose baby will make their debut before the curtain officially rises.

The more times you delivered early and the earlier you were (24 vs. 28 weeks), the more likely you are to be early again. There are other risk factors for preterm delivery, like a history of cervical surgery, UTIs and genital tract infections during pregnancy, smoking, substance abuse, low maternal pre-pregnancy weight, and short inter-pregnancy interval. But none is nearly as strong as a previous history of a preterm birth. Simply stated, a history of preterm birth is the odds-on favorite for a preterm birth in your next pregnancy. So why do we care about when and if a preterm delivery occurs? Sure, we love to win a good family/office pool as much as the next gal, but you can be sure that whether we take home the pot is not what’s perturbing us. What keeps us on our toes is the following: babies who are born premature (a.k.a. early) have a much higher risk of serious morbidity and even mortality, particularly in the first year of life.

Nothing good comes out of an early delivery, except maybe a few less pounds gained and stretch marks formed. Pregnancy was meant to go the distance, that is, 39 weeks, and when it is cut short, bad things can happen to your baby. To prevent a recurrent preterm birth, your OB will be on your speed dial—and you on theirs! We want to know how and what you are feeling. We also like to see your cervix via vaginal ultrasounds every couple of weeks. These checkpoints can clue us into what might be coming (a.k.a. another preterm birth). If things start to change, say, the length of the cervix gets shorter or the cervical opening begins to dilate, we will call “Freeze” and often admit you to the hospital for medication and monitoring. Additionally, women who went early before will usually be prescribed weekly IM shots, which are progesterone injections starting between 16–24 weeks. And while the shots may be a big pain in the butt  —we’re not going to lie; that needle is long!—they are a big player in the prevention of recurrent preterm birth.

Although we can never be sure whose baby is likely to break out of the womb before his/her time is up, we can narrow down the lineup to a few of the most likely candidates. And because we don’t like to make any wrongful convictions, we use the evidence (a.k.a. what happened in your previous pregnancy) to hone in on those who have planned a successful escape in the past. While we may put you on high surveillance (frequent office visits, ultrasounds, weekly injections, and possibly even reduced activity) to encourage this pregnancy to go the distance, it’s a small price to pay for your baby’s safety. While we may not be spot on with the weight and date of your little one, we will be on the money with how best to prevent a recurrent preterm birth. Here, we are not willing to gamble!