Leading gynaecologists are advising pregnant women carrying babies weighing 4.2 kilograms or more to be aware of increased risks during vaginal delivery. Experts emphasize that while fetal weight is a significant factor, it should not be the sole determinant of delivery mode. Safe outcomes hinge on meticulous assessment, continuous monitoring during labour, and individualised decision-making by medical professionals.
Forcing a vaginal delivery of a significantly large baby, a condition known as foetal macrosomia, can lead to severe complications for both mother and child. These maternal risks include excessive postpartum haemorrhage, uterine rupture, and tears to the cervix and vagina, potentially resulting in long-term conditions like vesicovaginal fistula. The babies themselves may face fractures, nerve damage, and oxygen deprivation, which can have lasting neurological consequences.
A particular concern in large baby deliveries is shoulder dystocia, where a baby’s shoulders become lodged after the head has emerged. Although more common with larger infants, this obstetric emergency can occur with babies of any size, as individual maternal pelvic structures vary considerably. Gynaecologists stress that a baby weighing as little as 3.2kg can still present this challenge.
Reliance on early ultrasound scans for fetal weight estimation is cautioned against, as babies experience substantial growth in the final weeks of pregnancy. Experts recommend updated assessments closer to the due date to provide a more accurate weight estimate and inform delivery planning. The ultimate goal is to prioritize maternal and fetal safety through evidence-based, individualized care.
Data indicates that some women have experienced severe complications, including death from postpartum haemorrhage, after delivering babies exceeding 4kg. This underscores the critical importance of appropriate management strategies. Nigeria, unfortunately, faces a high maternal mortality rate, with postpartum haemorrhage being a primary contributor globally.
While a baby weighing between 4kg and 5kg is generally classified as having a large birth weight, experts like Professor Rotimi Akinola assert that this designation does not automatically necessitate a caesarean section. He explains that guidelines vary, with some setting the threshold at 4kg and others slightly higher. The general consensus is that the larger the baby, the greater the potential risks, including prolonged labour and postpartum bleeding.
Professor Akinola further elaborates that shoulder dystocia is a significant danger, but its occurrence is not solely tied to macrosomia, as individual pelvic dimensions play a crucial role. He advocates for close monitoring of labour progression, stating that the labour itself provides critical indicators for determining the safest course of action, including when an emergency caesarean section might be necessary.
Overdistension of the uterus due to large babies or multiple pregnancies can impede effective contraction post-delivery, increasing the risk of postpartum haemorrhage. However, many women can successfully deliver large babies vaginally with good labour progress and expert assistance. Blanket decisions based solely on estimated weight are often seen as defensive medicine rather than best practice.
Professor Chris Aimakhu, Second Vice President of SOGON, generally recommends caesarean sections for babies estimated at 4kg or more, defining fetal macrosomia as such. He highlights contributing factors like maternal diabetes, obesity, genetics, and prolonged gestation. Poorly controlled blood sugar levels in mothers are a significant driver of fetal overgrowth.
While women with larger body frames may naturally carry larger babies and deliver vaginally, antenatal care is paramount in identifying risks. Professor Aimakhu advises counselling women with babies estimated at 4kg or more for caesarean sections, as the baby’s head size may exceed cervical dilation, complicating vaginal birth and increasing the risk of obstruction and injury.
For estimated fetal weights between 3.5kg and 4kg, a carefully supervised trial of labour might be considered, provided there are no prior caesarean sections and labour progresses normally. Forcing vaginal delivery in suspected macrosomia cases can lead to severe maternal injuries and potential harm to the infant, including fractures and neurological damage.
Ultimately, late pregnancy scans are vital for accurate fetal weight estimation. If a woman declines a caesarean section after thorough counselling, healthcare providers must meticulously document the discussion and her informed decision. This transparency protects both patient and practitioner, ensuring that delivery choices are made with a full understanding of the associated risks.
