Water births are increasingly popular among women looking for options. A recent study found that midwives at a birthing centre used water immersion nearly 60 per cent of the time.  Now a case report published in the Canadian Medical Association Journal (CMAJ) highlights one particular risk.  

The case in question involves a home birth.  A full-term baby was born in a hot tub. The birth was attended by a midwife. The baby weighed nearly three and a half kilograms at birth (7 lbs 11 oz).   She was vigorous at birth, and breast fed well from the outset. However, eight days following the hot tub birth, the baby spiked a fever of 39.1 C.  The baby was brought to the hospital, where doctors found that she was working harder to breathe than a normal eight-day old.  A chest X-ray showed pneumonia in the right lung. 

A high fever in a newborn was likely caused by sepsis or an infection in the bloodstream. The baby was admitted to hospital and put on intravenous antibiotics. Later the same day, the baby's breathing deteriorated to the point that she had to be put on a ventilator and transferred to the intensive care unit.

How did doctors make the connection between the hot tub and what happened eight days later? The baby failed to respond to broad spectrum antibiotics and antiviral drugs, and standard blood testing failed to identify the germ causing the newborn's infection. But a strong inflammatory response in the baby's lungs suggested Legionella might be the cause — Legionella being the bacterium that causes legionnaires' disease. Testing for Legionella came back positive.  Doctors started the antibiotic azithromycin, and the newborn's condition began to improve. The baby was able to come off the ventilator she had been on for five weeks. 

The germ was not found in the hot tub. By the time doctors had identified the infection, the hot tub had been disinfected.  Still, there are several solid case reports of newborns contracting Legionella following water births.  

Why do water births increase the risk of this particular infection? The hot tub in which the baby was born had been filled three days prior to the birth. It is theorized by the authors of the case report that the 3-day window gave time for bacteria in the water to multiply, increasing the concentration of bacteria in the water. Other factors may include inadequately disinfecting the birthing tank, using a contaminated water source and using jetted tubs. Other sources of bacteria include debris that falls into an uncovered tub, and bacteria that are lodged in the biofilm or scum found inside the hot tub drain.  Legionella thrive at water temperatures between 20 and 42 C. 

The doctors who reported the case say that this particular bacterium has been linked to contaminated water systems at home and in hospital. Exposure to Legionella can also occur through inhalation of contaminated water in humidifiers, baths or birthing tanks used in water births.  

What are the benefits of water births? A 2009 Cochrane review found that the use of a birthing pool during the first stage of labour can help lower pain, reduce the need for epidural anesthesia and make the labour go faster. As for giving birth in the water, the method increased patient satisfaction in one study. But overall, there was insufficient evidence for or against giving birth in the water. Without good quality research, it's hard to know whether to recommend water births or condemn them. In case reports, newborns have contracted sepsis from other bacteria. Other risks from water births that have been documented include raising or lowering the baby's body temperature, aspirating bath water into the baby's lungs, and seizures.

How can the risk be managed? The authors of the case report in CMAJ say that people who attend births in Canada should follow recommendations from the United Kingdom and the United States regarding water births. Jetted pools or pools with re-circulating water pumps should not be used. Water tanks should never be pre-filled and left for days prior to the birth.  The tank itself needs to be properly disinfected. That said, concerns have been raised about the safety of disinfectants in newborns, and little data to reassure doctors. 

The authors add that doctors should also consider testing for Legionella in every newborn who contracts a fever following a water birth. Last year, the American College of Obstetricians and Gynecologists (ACOG) put out new recommendations that say women should not give birth immersed in water because of a lack of good evidence showing whether it is safe and beneficial. Until the evidence changes, that seems like sensible advice.