Bleeding during vaginal or operative delivery is always of prime concern. Despite significant progress in obstetric care 125,000 women die from obstetric hemorrhage annually in the world.
The incidence of caesarean delivery is increasing, and the average blood loss during caesarean delivery (1000 mL) is double the amount lost during vaginal delivery (500 mL).
Caesarean section (CS) rate as high as 25-30% in many areas of the world. In Egypt the CS rate is 27.6 %, in United States of America, from 1970-2009 the CS rate rose from 4.5-32.9%, and declined to 32.8% of all deliveries at 2010. In spite of the various measures to prevent blood loss during and after caesarean section, post-partum hemorrhage (PPH) continues to be the most common complication seen in almost 20% of the cases, and causes approximately 25% of maternal deaths worldwide, leading to increased maternal morbidity and mortality. Indeed we need to reduce the bleeding during and after caesarean sections aiming for reducing the morbidity and mortality rate due to obstetric hemorrhage, which can be life threatening.
The hematocrit level falls by 10% and blood transfusion is required in 6% of women undergoing caesarean delivery versus 4% of women who have a vaginal birth. Numerous methods for performing caesarean section exist targeting a safe delivery for the infant with minimum maternal morbidity. Operative morbidity includes hemorrhage, anemia, and blood products transfusion may be required associated with many risks and complications.
Women who undergo a caesarean delivery are much more likely to be delivered by a repeat operation in subsequent pregnancies. For women undergoing subsequent cesarean, the maternal risks are even greater like massive obstetric hemorrhage, hysterectomy, admission to an intensive care unit, or maternal death. Medications, such as oxytocin, misoprostol and prostaglandin F2α, have been used to control bleeding postoperatively.
The uterus is a smooth muscle whose contraction is modulated most directly by intrinsic or extrinsic oxytocin. During pregnancy the spiral arteries within the uterus and beneath the placenta enlarge to provide adequate perfusion to the placenta. After separation of the placenta the uterine smooth muscle cells contract in a pincer-like action to pinch the spiral arteries closed. When uterine contraction is inadequate (approximately 4-6% of normal pregnancies) the spiral arteries continue to bleed. If not addressed the bleeding can be excessive, even leading to maternal death. Approximately 5-8 out of 1,000 cesarean sections require hysterectomy to control bleeding.
Release of calcium ions from sarcoplasmic reticulum stores is the immediateinitiator of contraction, and calcium's diffusion from the muscle filaments andre-uptake by the sarcoplasmic reticulum results in relaxation of contraction. Insome smooth muscles cold enhances contraction; perhaps by slowing the re-uptake of calcium.
