New Research Shows Why Every Week of Pregnancy Counts

[BellyBelly]

New Research Shows Why Every Week of Pregnancy Counts
By MELINDA BECK

This time of year, some hospitals see a small uptick in baby deliveries thanks to families eager to fit the blessed event in around holiday plans or in time to claim a tax deduction. Conventional wisdom has long held that inducing labor or having a Caesarean section a bit early posed little risk, since after 34 weeks gestation, all the baby has to do was grow.

But new research shows that those last weeks of pregnancy are more important than once thought for brain, lung and liver development. And there may be lasting consequences for babies born at 34 to 36 weeks, now called "late preterm."

New research shows that the last weeks of pregnancy are more important than once thought for brain, lung and liver development.

A study in the American Journal of Obstetrics and Gynecology in October calculated that for each week a baby stayed in the womb between 32 and 39 weeks, there is a 23% decrease in problems such as respiratory distress, jaundice, seizures, temperature instability and brain hemorrhages.

A study of nearly 15,000 children in the Journal of Pediatrics in July found that those born between 32 and 36 weeks had lower reading and math scores in first grade than babies who went to full term. New research also suggests that late preterm infants are at higher risk for mild cognitive and behavioral problems and may have lower I.Q.s than those who go full term.



What's more, experts warn that a fetus's estimated age may be off by as much as two weeks either way, meaning that a baby thought to be 36 weeks along might be only 34.

The American College of Obstetricians and Gynecologists, the American Academy of Pediatrics and the March of Dimes are now urging obstetricians not to deliver babies before 39 weeks unless there is a medical reason to do so.

"It's very important for people to realize that every week counts," says Lucky E. Jain, a professor of pediatrics at Emory University School of Medicine.

It's unclear how many deliveries are performed early for nonmedical reasons. Preterm births (before 37 weeks) have risen 31% in the U.S. since 1981 -- to one in every eight births. The most serious problems are seen in the tiniest babies. But nearly 75% of preterm babies are born between 34 and 36 weeks, and much of the increase has come in C-sections, which now account for a third of all U.S. births. An additional one-fifth of all births are via induced labor, up 125% since 1989.

Many of those elective deliveries are done for medical reasons such as fetal distress or pre-eclampsia, a sudden spike in the mother's blood pressure. Those that aren't can be hard to distinguish. "Obstetricians know the rules and they are very creative about some of their indications -- like 'impending pre-eclampsia,'" says Alan Fleischman, medical director for the March of Dimes.

Why do doctors agree to deliver a baby early when there's no medical reason? Some cite pressure from parents. "'I'm tired of being pregnant. My fingers are swollen. My mother-in-law is coming' -- we hear that all the time," says Laura E. Riley, medical director of labor and delivery at Massachusetts General Hospital. "But there are 25 other patients waiting, and saying 'no' can take 45 minutes, so sometimes we cave."

There's also a perception that delivering early by c-section is safer for the baby, even though it means major surgery for the mom. "The idea is that somehow, if you're in complete control of the delivery, then only good things will happen. But that's categorically wrong. The baby and the uterus know best," says F. Sessions Cole, director of newborn medicine at St. Louis Children's Hospital.

He explains that a complex series of events occurs in late pregnancy to prepare the baby to survive outside the womb: The fetus acquires fat needed to maintain body temperature; the liver matures enough to eliminate a toxin called bilirubin from the body; and the lungs get ready to exchange oxygen as soon as the umbilical cord is clamped. Disrupting any of those steps can result in brain damage and other problems. In addition, the squeezing of the uterus during labor stimulates the baby and the placenta to make steroid hormones that help this last phase of lung maturation -- and that's missed if the mother never goes into labor.

"We don't have a magic ball to predict which babies might have problems," says Dr. Cole. "But we can say that the more before 39 weeks a baby is delivered, the more likely that one or more complications will occur."

In cases where there are medical reasons to deliver a baby early, lung maturation can be determined with amniocentesis -- using a long needle to withdraw fluid from inside the uterus. But that can cause infection, bleeding or a leak or fetal distress, which could require an emergency c-section.

Trying to determine maturity by the size of the fetus can also be problematic. Babies of mothers with gestational diabetes are often very large for their age, but even less developed for their age than normal-size babies.

Growing beyond 42 weeks can also pose problems, since the placenta deteriorates and can't sustain the growing baby.

Making families aware of the risks of delivering early makes a big difference. In Utah, where 27% of elective deliveries in 1999 took place before the 39th week, a major awareness campaign has reduced that to less than 5%. At two St. Louis hospitals that send premature babies to Dr. Cole's neonatal intensive-care unit, obstetricians now ask couples who want to schedule a delivery before 39 weeks to sign a consent form acknowledging the risks. At that point, many wait for nature to take its course, says Dr. Cole.

[Inanna]

That's a good article Kelly - I wonder if there is some recent research into the magical 42 week cut off?
We have heard for a long time that 42 weeks is the max - but I am wondering if there is a more recent study?

[AliB]

Hi Innana

WRT your question, Kelly posted this article a couple of weeks ago - may be of interest if you haven't seen it:
https://www.bellybelly.com.au/forums...trimester.html

[Inanna]

Thanks Ali!

[BellyBelly]

Yeah its a great article, but they still have this scary 42 week headset thing, its one thing I dont agree with in this article.

[farmgirl77]

Interesting...my little IVF DS was born at 37wks + 4 days by emergency c section after my waters broke but labour did not progress. Being IVF we knew exactly the length of gestation we were up to.

After his birth we had a few probs that ring true with this article - he was on the little side of normal (2.8kg), jaundiced (although not enough to need the lights), was very sleepy, had feeding probs, lost greater than 10% birth weight and was slow to put weight back on. We were readmitted to special care nursery only a few days after our discharge from hosptial because of the problems we experienced.

We were told on readmittance that although considered 'full term' our DS was acting 'prem'. One of the few things we actually agreed with the peds and other medical staff on was that if my waters had not broken, he prob would have been a baby that 'naturally' would have gone 41 or 42wks - for his own good and development!

I understand the need for wanting to feel in control and can understand people desire to have elective c sections, but I guess I have now also seen things from the other side of the fence...

[Early Kids]

Good article, I hope that people will begin to realise that its best for baby to actually make it to your due date!

farmgirl, I'm curious... is there any other reason for your c/s other than labour failing to start?

[happymum24]

This article is great.

My 2nd son was born by elective c/s at 37+5 weeks. My gut told me it was too early but my OB told me babies are all cooked by 37 weeks. My son's lungs weren't developed even at that gestation and he developed a premature lung disease and ended up in the SCU on oxygen, tube fed etc.. for 10 days. It was horrible.

So when it was time for my third c/s the same OB apologised to me for recommending the c/s when it was too early and said that he now did c/s at 39 weeks....I ended up going into labour the day before my elective c/s and had a perfect, healthy baby boy who knew he was ready!

[farmgirl77]

Hi Sally,
As far as I know, not really. The decision to do the emerg c sec was based on 1. my waters had been broken for 24hrs and we had been told that after 24hrs there is a greater infection risk 2. I had only dilated 1cm whist in the birthing suite and on the drip (was at 3cm when we came in and only 4cm 10hrs later), and 3. without the drip, I was not really having any contractions on my own IYKWIM? At one stage DS heatbeat droped and he was a bit distressed, but it was not the defining factor except that is scared me (and dh) and at the stage that my ob was considering options 1. I was exhausted (I had been awake 36+hrs) 2. I did not feel that my body was feeling any differenly eg the pain from the contractions was not moving, and 3. when I overheard the MW say that DS was showing some distress, I basically said get him out alive and do it now. I think the rocky conception/pg prob made me fearful of my bodies ability to keep going and to have my baby naturally.

When I asked if there was any obvious reason why labour had 'failed to progress' (gee I hate that term), the answer was 'no'.

Now having written all that, the other side to your question is the mental one, which is, I think I had conditioned myself to belive that DS birth would be c-sec, because my body had 'failed' to get pg naturally, needed heparin/asprin to maintain the pg (had 'failed' again by not being able to maintain a pg by its self) so I think deep down I expected to 'fail' at a natural delivery. I think that because I had not really though/discussed this at all (and still have not really), I was just focused on getting a live baby out rather than how I was feeling and the impact that all these other factors would have on how I thought about the birth experience. Surprise surprise I have been suffering PND

Happymum - I'm sorry to read about your experience with your 2nd DS, and hope that there have been no long term effects. Cant imagine how hard it would have been for you. Glad that you had a better experience with your third!
FG

[kungfubecca]

Wow it makes me glad my babies like tocamp until 41 weeks plus 2 for 2 born without jaundice. I also think going full term is good for mum too. Everyone is different but I would feel robed. Of my last few weeks of pregnancy and missing out if it wasnt for a good reason could make me depressed.