Maternal Oxygen Administration for Fetal Distress

Prophylactic Maternal Low Flow Nasal Oxygen Administration During the Second Stage of Labor for Fetal Distress

Supplementary oxygen is routinely administered to patients, even those with adequate oxygen saturations, in the belief that it increases oxygen delivery. However, oxygen delivery depends not just on arterial oxygen content but also on perfusion. Maternal oxygen administration has been used in an attempt to lessen fetal distress by increasing the available oxygen from the mother. However, the effect of supplemental maternal oxygen therapy on fetal acid base status has been debated for more than seven decades. Hypothesis: Prophylactic maternal low flow nasal oxygen administration during the second stage of labor can relieve fetal distress.

A report from the cochran library (Cochrane Database Syst Rev. 2012 Dec 12;12:CD000136.): Too little evidence to show whether oxygen administration to the woman during labour is beneficial to the baby. Some babies show signs of distress, such as unusual heart rates or the passing of a bowel motion (meconium) during their mother's labour. This may be caused by a lack of oxygen passing from the woman to the baby through the placenta. Sometimes, women may be encouraged to breathe extra oxygen through a facemask (oxygen administration) to increase the oxygen available to the unborn baby. A review of two trials found too little evidence to show whether oxygen administration to the woman during the second stage of labour is beneficial to the baby. No trials of oxygen administration when the baby is showing signs of distress were found. Further research is needed.

Patients randomized to the group will receive sham administered by nasal catheter. The therapy will continue until after delivery

Patients randomized to the group will receive oxygen administered by low flow nasal oxygen at a flow rate of 2 L/min. The therapy will continue until after delivery

Oxygen will be administered by nasal catheter at a flow rate of 2 L/min. The therapy will continue until after delivery

Immediately after delivery (within 30-60 seconds of birth), umbilical cord arterial blood gas sample will be obtained.

The Apgar scale is determined by evaluating the newborn baby on five simple criteria on a scale from 0 to 2, then summing up the five values thus obtained. The resulting Apgar score ranges from 0 to 10. The five criteria are summarized using words chosen to form a backronym (Appearance, Pulse, Grimace, Activity, Respiration). The infant is given a score of 0, 1 or 2. The scores are added up and the total sum is their Apgar score. The test is generally done at one and five minutes after birth, and may be repeated later if the score is and remains low. Scores 7 and above are generally normal, 4 to 6 fairly low, and 3 and below are generally regarded as critically low.

Immediately after delivery (within 30-60 seconds of birth), radial artery blood gas sample will be obtained.

Immediately after delivery (within 30-60 seconds of birth), umbilical cord venous blood gas sample will be obtained.

Inclusion Criteria: at term singleton primigraida cephalic presentation spontaneous or induced labor normal labor normal FHR tracings in the first stage at the onset of second stage Exclusion Criteria: respiratory disease cardiovascular disease diabetes mellitus or insulin-treated gestational diabetes mellitus hypertension or preeclampsia oligohydramnios fetal growth restriction placental abruption anemia disorders in oxygen saturations received oxygen therapy in the first stage

Qian G, Xu X, Chen L, Xia S, Wang A, Chuai Y, Jiang W. The effect of maternal low flow oxygen administration during the second stage of labour on umbilical cord artery pH: a randomised controlled trial. BJOG. 2017 Mar;124(4):678-685. doi: 10.1111/1471-0528.14418.

Chuai Y, Jiang W, Xu X, Wang A, Yao Y, Chen L. Maternal oxygen exposure may not change umbilical cord venous partial pressure of oxygen: non-random, paired venous and arterial samples from a randomised controlled trial. BMC Pregnancy Childbirth. 2020 Sep 4;20(1):510. doi: 10.1186/s12884-020-03212-3.