Welcome to November! It’s hard to believe the fall is coming to a close, especially here in San Francisco where the weather has been sunny! This week’s most popular women’s health articles are all pregnancy and obstetrics-related. Three of the articles seek to explain risk factors for preterm birth: obesity and prior cesarean delivery. The fourth article provides an update on the fight to curb the spread of Zika, and finally we take a “sunny-side-up” look at OP fetal positioning.
1. Visceral fat and Preterm Birth
A group of prestigious researchers and OBGYNs, funded by AMAG Pharmaceuticals (maker of the progesterone shot), recently published a supplement focusing on preterm birth, “The Most Important Challenge in Today’s Obstetrics.” The preterm birth rate in the US has been difficult to decrease, so better understanding of what contributes to this outcome is important. In the supplement, Dr. Gyamfi-Bannerman reminds us that both high and low BMI are associated with higher risk of preterm birth. The theory behind the link between high BMI and PTB? Adipokines in visceral fat are believed to cause inflammation, which in turn increases risk of preterm birth.
2. Obesity and Labor
The next article continues along the same theme, examining whether it’s better for morbidly obese women to undergo labor or to have a scheduled cesarean section. Currently, high BMI is not an indication for cesarean delivery. However, it is a risk factor for requiring a cesarean delivery. A vicious cycle ensues: high BMI increases the risk of requiring labor induction, but it is also linked to higher risk of failure of induction and thus cesarean delivery.
3. Prior Cesarean Delivery and Preterm Birth
A retrospective study published in AJOG examined severe maternal complications for all births in 16 hospitals for one year. The authors found that severe maternal morbidity increased the risk of preterm birth (as one might expect). However, they also found that 63% of women who experience placental hemorrhage had a prior cesarean delivery, illuminating yet another long term risk of cesarean delivery- future preterm birth.
4. Occiput Posterior Position
Any mother or obstetrician who has dealt with a “sunny-side-up” baby knows that this cheerful term does not do justice to the difficult position. Occiput posterior positioning (fetus looking towards the belly instead of the backbone- OA) in the birth canal makes vaginal delivery more difficult. Occiput posterior positioning occurs in 1-5% of deliveries and is more likely after artificial rupture of membranes and with an epidural. Some other risk factors include nulliparity, maternal age over 35, and birth weight over 4000 grams.
5. Stopping Zika with Bateria
Stopping the spread of Zika virus is now one of the great challenges facing us because of the devastating effects it has on developing fetuses, and perhaps adults as well. Stat reported that the Wellcome Trust, the Gates Foundation, and the US and UK governments are funding an $18 million campaign to release bacteria to attack the mosquitoes that carry Zika and dengue viruses. The Wolbachia bacteria will be released in cities in Brazil and Columbia, and researchers will monitor if this decreases cases of the relevant diseases.