As many as 10% of babies are delivered after having released their first fecal matter, referred to as “meconium”, which subsequently enters the amniotic fluid they inhabit. Such an event puts them at risk of inhaling meconium-stained amniotic fluid (MSAF), which in turn can lead to the potentially fatal respiratory disease called MAS (meconium aspiration syndrome).

In the 1970s, doctors had the idea to use suction upon delivery if a baby was known to be at risk for inhaling MSAF. By suctioning the mouth and nose as soon as possible, they hoped to remove any MSAF and reverse any ill effects that could lead to MAS. With little and some conflicting evidence regarding its usefulness, the procedure has since become standard and widespread.

Since suctioning for MSAF at the instant of birth is not without its risks, some researchers have questioned the wisdom of this procedure. Like most procedures involving pregnancy and childbirth, clinical trials on the effectiveness of this intervention are few and far between. One key principle of modern research is that of “informed consent,” ensuring that research subjects are fully informed before actively choosing to participate. In the case of obstetrics, informed consent must be acquired from parents, who are understandably wary of experiments involving their newborn children.

Despite this ethical limitation, investigators of a recent study were able to lead the first randomized controlled trial of newborn suctioning for MAS prevention, arguing that the study posed minimal risk according to previously published research about suctioning. Their results, published in the August 14, 2004 issue of The Lancet , show that suctioning provided no benefit over not suctioning.

About the Study

The study was conducted between March 2000 and October 2001 at 11 hospitals in Argentina and one in the United States. During this period, approximately 9% (n=3249) of all babies were exposed to meconium-stained amniotic fluid (MCAS) prior to birth. Of these, 2514 babies were enrolled on the spot and received either oral and nasal suctioning before delivery of the shoulders (n=1263), or no suctioning before delivery (n=1251).

The Findings

No difference was seen between treatment groups. Fifty-two babies who received suctioning (4%) and 47 of those who didn’t (4%) contracted MAS.

How Does This Affect You?

The results of this study indicate that the common practice of suctioning babies to prevent serious respiratory disease is maybe unnecessary. What the study does not address, however, is how to prevent MAS in the 4% of children who acquired it. More research into the mechanisms by which infants develop respiratory diseases― in particular, MAS― will be needed to answer this question.

Doctors perform many procedures – all with some degree of risk – simply because they seem to make sense; not because research supports their effectiveness. Suctioning meconium-stained amniotic fluid from the respiratory tract of newborns is a classic example. The current study notwithstanding, most of us would agree that the high ethical standards that protect research subjects should always be enforced. Such vigilance comes at a price, however, since we may never know whether common medical practices really work. This is especially true when those who stand to benefit cannot give their informed consent.