Labor Day Holiday: let's celebrate Laboring Ladies
Updates on this arduous and risky women's work
Many of us are enjoying the fading summer daze with a labor-less holiday weekend. Picnics, BBQs, ball games, hiking, swimming - name your favorite past time.
I doubt anyone would say… childbirth.
However, when I hear labor… I think delivery, as in babies. So this newsletter is focused on this most important activity.
Let us then, ‘get started’.
Signaling Labor onset
Researchers search for biomarkers that trigger uterine contractions.
In this study, we hypothesize that i) exosomes act as carriers of signals in utero-placental compartments and ii) exosomes reflect the physiologic status of the origin cells. The primary aims of this study were to determine exosomal contents in exosomes derived from primary amnion epithelial cells (AEC). We also determined the effect of oxidative stress on AEC derived exosomal cargo contents. -S Sheller et al
They found that the stressed exosomes contained p38 MAPK which is linked to delivery. Some effects include placental aging and sterile uterine inflammation, reduction of progesterone, consequently promoting uterine contractions.
I described the onset of labor in primates in a prior newsletter. Research shows that adrenal steroids from the maturing fetus are aromatized to estrogens in the placenta and circulated in the mother, leading to smooth muscle contractions.
Induction Methods - which are best and when?
When spontaneous contractions are missing or lacking, obstetricians turn to induction maneuvers. The cervix is ripened either mechanically, by inserting a water-filled balloon catheter exerting pressure on it to open, or hormonally, with prostaglandins.
Balloon catheter method has a better safety profile for neonates when compare to data from vaginal hormone outcomes. There were fewer adverse events such as acidosis, poor APGAR scores, or neonatal intensive care unit admission. There was no difference in maternal adverse events or cesarean rates between the two methods.
And when do we induce labor?
In August 2018, A Randomized Trial of Induction vs Expectant Management (ARRIVE) trial was published in the New England Journal of Medicine. This trial found that low-risk, nulliparous patients who were induced at 39 weeks’ gestation had a 16% relative risk reduction in cesarean delivery (CD) as compared with expectant management. Our objective was to evaluate if the publication of this trial was associated with observable obstetric practice changes in the US. We hypothesized the rate of 39-week induction would increase and CD would decrease for low-risk nulliparous patients after publication and dissemination of the ARRIVE trial.
Indeed, OB practice data revealed an increase in 39-week induction rates was associated with a reduction in CD rates for low-risk nulliparous patients across the US.
How long to leave to labor?
So when do we give up on labor contractions and resort to surgical interventions? What ‘best practice’ can guide us?
Extending the length of labor in nulliparous women with singleton gestations, epidural anesthesia, and prolonged second stage decreased the incidence of cesarean delivery by slightly more than one-half, compared with usual guidelines.
Labor may not naturally accelerate in some women until a cervical dilatation of at least 5 cm, so any interventions to expedite labor before reaching this point in dilatation, may not be indicated. Women giving birth to their first child and progressing at the slowest rates, may take 7 hours to progress from 4 to 5 cm dilation, over 3 hours to progress from 5 to 6 cm, and up to 9 hours to progress from 6 to 10 cm.
And for those with persistent back pain, sterile water injections provide effective pain relief. Data was collected between 2012 and 2017 in British and Australian maternity units. More than one thousand women in labor with severe back pain were given either water injections or a placebo of saline solution. Twice as many of the women who received the water injections reported their pain reduced by at least half, for 90 minutes or longer. Other than the transient pain of the initial injections, the procedure is free of side effects, low-cost and is suitable for use in a wide range of health care and low-resource settings.
Women face death to deliver
And last but not least, we discussed the tragedy of maternal/ neonatal deaths occurring in areas of poor resources. This past BioMedWorks newsletter describes real life innovations that greatly enhance survival in mom and baby.
Showing science and engineering ‘labor’ at its best.
REFERENCES
S Sheller, et al. (2016) Amnion-Epithelial-Cell-Derived Exosomes Demonstrate Physiologic State of Cell under Oxidative Stress. PLoS ONE 11(6): e0157614. https://doi.org/10.1371/journal.pone.0157614
MN Jones et al. Balloon catheters versus vaginal prostaglandins for labour induction (CPI Collaborative): an individual participant data meta-analysis of randomised controlled trials, The Lancet (2022). DOI: 10.1016/S0140-6736(22)01845-1
RWood et al. Rates of Induction of Labor at 39 Weeks and Cesarean Delivery Following Publication of the ARRIVE Trial, JAMA Network Open (2023). DOI:10.1001/jamanetworkopen.2023.28274
AC Gimovsky, et al. Randomized controlled trial of prolonged second stage: extending the time limit vs usual guidelines, American Journal of Obstetrics and Gynecology (2016). DOI: 10.1016/j.ajog.2015.12.042
OT Oladapo, et al. (2018) Progression of the first stage of spontaneous labour: A prospective cohort study in two sub-Saharan African countries. PLoS Med 15(1): e1002492.doi.org/10.1371/journal.pmed.1002492
N Lee, et al. Cesarean delivery rates and analgesia effectiveness following injections of sterile water for back pain in labor: A multicentre, randomized placebo controlled trial. EClinicalMedicine (2020). DOI:10.1016/j.eclinm.2020.100447