When a woman has difficulties in the second, or pushing, stage of labour, the doctor can use forceps or a vacuum pump to pull the baby through the birth canal. That practice, however, has fallen out of favour in recent years, as caesarean section has become the preferred option - partly because of concerns about the risks of using forceps and vacuums. These potential risks include skull fracture or internal bleeding in newborns, and tissue damage in mothers.
However, performing a C-section during the second stage of labour also presents risks, like increased odds of haemorrhage and bladder damage in mothers. Therefore, some have questioned the wisdom of the decline in instrument-assisted delivery.
Researchers looked at 3,189 American women who underwent an unplanned C-section. In 640 of these cases, doctors had first attempted to deliver using forceps, vacuum or both. It was found that overall, rates of certain fetal and maternal complications were higher during a trial of instrument-assisted delivery. Mothers were more likely to develop an infection, bruising or fluid buildup at their incision site - nearly 3 percent versus 1 percent of women who had an immediate C-section. They also had a higher rate of failed local anaesthesia, which meant they had to be put under general anaesthesia - 8 percent, compared with 4 percent of the C- section-only group.
Some newborn complications were also more common with instrument-assisted attempts. One percent of infants developed brain damage due to oxygen deprivation, compared with 0.1 percent of those delivered by immediate C-section. They were also more likely to have a low Apgar score (a measure of heart rate, breathing and muscle tone five minutes after birth); just fewer than 2 percent had a low Apgar score, versus 0.6 percent among the other newborns. However, the researchers found, all 10 cases of brain damage were seen in cases where the fetal heart rate was a matter of concern during delivery. There was no evidence that the complication was due to skull damage from the forceps or vacuum. And when the researchers excluded cases with concerning fetal heart rate readings, there were no differences in the risks of any complications between the two groups of babies.
Fetal heart rate concerns were more common when doctors first attempted an instrument-assisted delivery: in 18 percent of cases, heart rate concerns prompted the C-section, compared with 14 percent of cases where the C-section was done immediately. The findings suggest that in the absence of heart rate problems, there is no increase in the risk of newborn complications.
Together with past research, the findings suggest that attempting an instrument-assisted delivery in the ‘properly selected patient’ minimises the risks to mothers without increasing the risks to newborns.